Spring学习笔记之 Spring IOC容器(二) 之注入参数值，自动组件扫描方式，控制Bean实例化方式，使用注解方式

 本节主要内容：
    1. 给MessageBean注入参数值
    2. 测试Spring自动组件扫描方式
    3. 如何控制ExampleBean实例化方式
    4. 使用注解方式重构JdbcDataSource, UserDAO, UserService

本文作者：souvc

本文出处：http://www.cnblogs.com/liuhongfeng/p/4582664.html 

1 给MessageBean注入参数值

1.1 问题

Spring可以通过配置文件为bean注入多种类型的属性, MessageBean类用于演示Spring的多种类型数据的注入方式, 这些类型数据和注入方式包括：

1. 注入基本值。

2. 注入Bean对象(请参考Unit 1案例)。

3. 直接集合注入。

4. 引用方式集合注入

5. 注入Spring表达式值。

6. 注入null或空字符串。

1.2 步骤

步骤一：新建工程，导入Spring API jar包

新建名为SouvcSpringIoC_02的web工程，在该工程导入5个jar包。

 

commons-logging.jar

spring-core.jar

spring-context.jar

spring-beans.jar

spring-expression.jar

 

网盘下载jar包 ：http://yunpan.cn/cQJhPMPRZeLH7  访问密码 2bf8

步骤二：新建Spring配置文件

在src目录下，新建Spring配置文件applicationContext.xml。该文件名为Spring默认的配置文件名，也可以自由定义名称。

applicationContext.xml文件中的代码如下所示：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    xsi:schemaLocation="
            http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
            http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
            http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd
            http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd
            http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
            http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd">






</beans>

 

步骤三：新建类MessageBean 添加基本值属性

新建类MessageBean，在该类中添加如下代码中的四个属性，并生成这几个属性对应的getter和setter方法；最后在execute方法获取这几个属性的信息，代码如下所示：

package com.souvc.bean;

public class MessageBean {
    private String moduleName;
    private int pageSize;
    private String username;
    private String password = "";

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getModuleName() {
        return moduleName;
    }

    public void setModuleName(String moduleName) {
        this.moduleName = moduleName;
    }

    public int getPageSize() {
        return pageSize;
    }

    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }

    public String execute() {
        System.out.println("moduleName=" + moduleName);
        System.out.println("pageSize=" + pageSize);
        System.out.println("username=" + username);
        System.out.println("password=" + password);
        System.out.println("---List信息如下---");
        return "success";
    }

}

步骤四：修改applicationContext.xml文件, 增加属性基本值注入

修改applicationContext.xml文件，为MessageBean的四个属性注入基本参数值，代码如图-3所示：

    <bean id="messagebean" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="测试基本属性"></property>
        <property name="pageSize" value="5"></property>
        <property name="username" value="daliu_it"></property>
        <property name="password" value="123456"></property>
    </bean>

步骤五：新建类Test1, 添加测试方法获取MessageBean对象测试注入结果

新建类Test1，在类中使用ApplicationContext的方式实例化Spring容器，获取MessageBean对象，并调用execute方法。

@Test
    public void test1() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        System.out.println(ac);

        MessageBean messagebean = ac.getBean("messagebean", MessageBean.class);
        System.out.println(messagebean.toString());
        messagebean.execute();
    }

步骤六：运行Test1类, 测试注入结果

运行Test1类，控制台输入结果

org.springframework.context.support.ClassPathXmlApplicationContext@65b4fad5: startup date [Wed Jun 17 11:16:13 CST 2015]; root of context hierarchy
com.souvc.bean.MessageBean@5d3e754f
moduleName=测试基本属性
pageSize=5
username=daliu_it
password=123456
---List信息如下---

控制台输出所示的信息，说明获取到了注入的基本属性值。

步骤七：为MessageBean添加集合属性,用于注入集合测试

1. 修改类MessageBean，在该类中添加如下加粗代码中的四个属性，并生成这几个属性对应的getter和setter方法；最后在execute方法获取这几个属性的信息，代码如下所示：

 

•     private List<String> someList;
•     private Set<String> someSet;
•     private Map<String,Object> someMap;
•     private Properties someProps;

 

package com.souvc.bean;

import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

public class MessageBean {
    private String moduleName;
    private int pageSize;
    private String username;
    private String password = "";

    
     private List<String> someList;
     private Set<String> someSet;
     private Map<String,Object> someMap;
     private Properties someProps;
    
    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getModuleName() {
        return moduleName;
    }

    public void setModuleName(String moduleName) {
        this.moduleName = moduleName;
    }

    public int getPageSize() {
        return pageSize;
    }

    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }

    
    
    public List<String> getSomeList() {
        return someList;
    }

    public void setSomeList(List<String> someList) {
        this.someList = someList;
    }

    public Set<String> getSomeSet() {
        return someSet;
    }

    public void setSomeSet(Set<String> someSet) {
        this.someSet = someSet;
    }

    public Map<String, Object> getSomeMap() {
        return someMap;
    }

    public void setSomeMap(Map<String, Object> someMap) {
        this.someMap = someMap;
    }

    public Properties getSomeProps() {
        return someProps;
    }

    public void setSomeProps(Properties someProps) {
        this.someProps = someProps;
    }

    
    
    public String execute() {
        System.out.println("moduleName=" + moduleName);
        System.out.println("pageSize=" + pageSize);
        System.out.println("username=" + username);
        System.out.println("password=" + password);
        System.out.println("---List信息如下---");
    
        for(String s : someList){
            System.out.println(s);
        }
        System.out.println("---Set信息如下---");
        for(String s : someSet){
            System.out.println(s);
        }
        System.out.println("---Map信息如下---");
        Set<String> keys = someMap.keySet();
        for(String key : keys){
            System.out.println(key+"="
                    +someMap.get(key));
        }
        System.out.println("---Properties信息如下---");
        Set<Object> keys1 = someProps.keySet();
        for(Object key : keys1){
            System.out.println(key+"="
                    +someProps.getProperty(key.toString()));
        }
        
        
        return "success";
    }

}

2. 修改applicationContext.xml文件，为MessageBean的四个属性注入集合参数值：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd">



    <!-- 加载properties文件为bean
        <util:properties id="jdbcProperties"
        location="classpath:db.properties" /> -->


    <bean id="messagebean" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="测试基本属性的注入"></property>
        <property name="pageSize" value="5"></property>
        <!-- 表达式注入 -->
        <property name="username" value="daliu_it"></property>
        <property name="password" value="123456"></property>
        <property name="someList">
            <list>
                <value>北京</value>
                <value>上海</value>
                <value>广州</value>
            </list>
        </property>
        <property name="someSet">
            <set>
                <value>James Gosling</value>
                <value>Martin fowler</value>
                <value>Larry Ellision</value>
            </set>
        </property>
        <property name="someMap">
            <map>
                <entry key="1001" value="Java语言基础"></entry>
                <entry key="1002" value="Java Web基础"></entry>
                <entry key="1003" value="Spring使用基础"></entry>
            </map>
        </property>
        <property name="someProps">
            <props>
                <prop key="username">root</prop>
                <prop key="password">1234</prop>
            </props>
        </property>
    </bean>


    <!-- 定义集合Bean 
        <util:list id="oneList">
        <value>Tom</value>
        <value>Andy</value>
        </util:list>
        <util:set id="oneSet">
        <value>James Gosling</value>
        <value>Martin fowler</value>
        </util:set>
        <util:map id="oneMap">
        <entry key="1001" value="Java语言基础"></entry>
        <entry key="1002" value="Java Web基础"></entry>
        </util:map>
        <util:properties id="oneProps">
        <prop key="username">root</prop>
        <prop key="password">1234</prop>
        </util:properties>
        
    -->

    <!-- 引用方式注入集合属性 
        <bean id="messagebean2" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="资费管理"></property>
        <property name="pageSize" value="5"></property>
        <property name="username" value="andy"></property>
        <property name="password" value="123"></property>-->

    <!-- 引用方式注入集合属性 
        <property name="someList" ref="oneList" />
        <property name="someSet" ref="oneSet" />
        <property name="someMap" ref="oneMap" />
        <property name="someProps" ref="oneProps" />
        </bean>-->
</beans>

3. 运行Test1类，控制台输出结果所示：

 

org.springframework.context.support.ClassPathXmlApplicationContext@42704baa: startup date [Wed Jun 17 11:30:43 CST 2015]; root of context hierarchy
com.souvc.bean.MessageBean@25961581
moduleName=测试基本属性的注入
pageSize=5
username=daliu_it
password=123456
---List信息如下---
北京
上海
广州
---Set信息如下---
James Gosling
Martin fowler
Larry Ellision
---Map信息如下---
1001=Java语言基础
1002=Java Web基础
1003=Spring使用基础
---Properties信息如下---
password=1234
username=root

控制台输出的信息，说明只需要通过配置Spring就可以为Bean注入集合参数值。

 

步骤八：测试引用方式集合注入

1.为Spring配置文件applicationContext.xml增加如下配置, 采用引用方式注入集合对象, 代码参考如下:

<!-- 定义集合Bean -->
    <util:list id="oneList">
        <value>Tom</value>
        <value>Andy</value>
    </util:list>
    <util:set id="oneSet">
        <value>James Gosling</value>
        <value>Martin fowler</value>
    </util:set>
    <util:map id="oneMap">
        <entry key="1001" value="Java语言基础"></entry>
        <entry key="1002" value="Java Web基础"></entry>
    </util:map>
    <util:properties id="oneProps">
        <prop key="username">root</prop>
        <prop key="password">1234</prop>
    </util:properties>



    <!-- 引用方式注入集合属性 -->
    <bean id="messagebean2" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="资费管理"></property>
        <property name="pageSize" value="5"></property>
        <property name="username" value="andy"></property>
        <property name="password" value="123"></property>

        <!-- 引用方式注入集合属性 -->
        <property name="someList" ref="oneList" />
        <property name="someSet" ref="oneSet" />
        <property name="someMap" ref="oneMap" />
        <property name="someProps" ref="oneProps" />
    </bean>

 

2. 增加Test2类测试如上配置, Test2代码如下:

package com.souvc.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.souvc.bean.MessageBean;

public class TestCase {

    @Test
    public void test1() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        System.out.println(ac);

        MessageBean messagebean = ac.getBean("messagebean", MessageBean.class);
        System.out.println(messagebean.toString());
        messagebean.execute();
    }

    @Test
    public void test2() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        MessageBean bean = ac.getBean("messagebean2", MessageBean.class);
        bean.execute();
    }
}

 

 

3. 执行Test2 有如下结果所示:

moduleName=资费管理
pageSize=5
username=andy
password=123
---List信息如下---
Tom
Andy
---Set信息如下---
James Gosling
Martin fowler
---Map信息如下---
1001=Java语言基础
1002=Java Web基础
---Properties信息如下---
password=1234
username=root

这个结果说明, 通过引用方式也可以为bean注入集合属性.

步骤九：利用 Spring表达式注入属性值

1.在工程的src下，新建属性文件db.properties，文件内容如下:

    user=scott

2. 修改applicationContext.xml文件，注入Spring表达式值，代码所示：

<!-- 加载properties文件为bean -->
 <util:properties id="jdbcProperties" location="classpath:db.properties" />
 
 
 <bean id="messagebean" class="org.tarena.bean.MessageBean">
 
  <!-- ================================================================ -->
 
  <property name="moduleName" value="资费管理"></property>
  <property name="pageSize" value="5"></property>
  <!-- 表达式注入 -->
  <property name="username" value="#{jdbcProperties.user}"></property>
 
  <property name="password">
   <null />
  </property>

3. 运行Test1类，控制台输出结果所示：

org.springframework.context.support.ClassPathXmlApplicationContext@68861f24: startup date [Wed Jun 17 11:41:35 CST 2015]; root of context hierarchy
com.souvc.bean.MessageBean@209444d1
moduleName=测试基本属性的注入
pageSize=5
username=daliu_it
password=123456
---List信息如下---
北京
上海
广州
---Set信息如下---
James Gosling
Martin fowler
Larry Ellision
---Map信息如下---
1001=Java语言基础
1002=Java Web基础
1003=Spring使用基础
---Properties信息如下---
password=1234
username=root

控制台输出信息，说明获取到了注入的Spring表达式值。

 

步骤十：注入null值

1. 修改applicationContext.xml文件，将属性password注入null值，代码如图-11所示：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd">



    <!-- 加载properties文件为bean-->
    <util:properties id="jdbcProperties"
        location="classpath:db.properties" />


    <bean id="messagebean" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="测试基本属性的注入"></property>
        <property name="pageSize" value="5"></property>
        <!-- 表达式注入 
            <property name="username" value="daliu_it"></property>-->
        <property name="username" value="#{jdbcProperties.user}"></property>
        <property name="password" >
        <null/>
        </property>
        <property name="someList">
            <list>
                <value>北京</value>
                <value>上海</value>
                <value>广州</value>
            </list>
        </property>
        <property name="someSet">
            <set>
                <value>James Gosling</value>
                <value>Martin fowler</value>
                <value>Larry Ellision</value>
            </set>
        </property>
        <property name="someMap">
            <map>
                <entry key="1001" value="Java语言基础"></entry>
                <entry key="1002" value="Java Web基础"></entry>
                <entry key="1003" value="Spring使用基础"></entry>
            </map>
        </property>
        <property name="someProps">
            <props>
                <prop key="username">root</prop>
                <prop key="password">1234</prop>
            </props>
        </property>
    </bean>


    <!-- 定义集合Bean -->
    <util:list id="oneList">
        <value>Tom</value>
        <value>Andy</value>
    </util:list>
    <util:set id="oneSet">
        <value>James Gosling</value>
        <value>Martin fowler</value>
    </util:set>
    <util:map id="oneMap">
        <entry key="1001" value="Java语言基础"></entry>
        <entry key="1002" value="Java Web基础"></entry>
    </util:map>
    <util:properties id="oneProps">
        <prop key="username">root</prop>
        <prop key="password">1234</prop>
    </util:properties>



    <!-- 引用方式注入集合属性 -->
    <bean id="messagebean2" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="资费管理"></property>
        <property name="pageSize" value="5"></property>
        <property name="username" value="andy"></property>
        <property name="password" value="123"></property>

        <!-- 引用方式注入集合属性 -->
        <property name="someList" ref="oneList" />
        <property name="someSet" ref="oneSet" />
        <property name="someMap" ref="oneMap" />
        <property name="someProps" ref="oneProps" />
    </bean>
</beans>

2. 运行Test1类，控制台输出结果：

org.springframework.context.support.ClassPathXmlApplicationContext@2996c1b0: startup date [Wed Jun 17 11:42:47 CST 2015]; root of context hierarchy
com.souvc.bean.MessageBean@195ed659
moduleName=测试基本属性的注入
pageSize=5
username=daliu_it
password=null
---List信息如下---
北京
上海
广州
---Set信息如下---
James Gosling
Martin fowler
Larry Ellision
---Map信息如下---
1001=Java语言基础
1002=Java Web基础
1003=Spring使用基础
---Properties信息如下---
password=1234
username=root

控制台输出所示的信息，说明获取到了注入的null值。

1.3 完整代码

MessageBean类的完整代码如下所示：

package com.souvc.bean;

import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

public class MessageBean {
    private String moduleName;
    private int pageSize;
    private String username;
    private String password = "";

    private List<String> someList;
    private Set<String> someSet;
    private Map<String, Object> someMap;
    private Properties someProps;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getModuleName() {
        return moduleName;
    }

    public void setModuleName(String moduleName) {
        this.moduleName = moduleName;
    }

    public int getPageSize() {
        return pageSize;
    }

    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }

    public List<String> getSomeList() {
        return someList;
    }

    public void setSomeList(List<String> someList) {
        this.someList = someList;
    }

    public Set<String> getSomeSet() {
        return someSet;
    }

    public void setSomeSet(Set<String> someSet) {
        this.someSet = someSet;
    }

    public Map<String, Object> getSomeMap() {
        return someMap;
    }

    public void setSomeMap(Map<String, Object> someMap) {
        this.someMap = someMap;
    }

    public Properties getSomeProps() {
        return someProps;
    }

    public void setSomeProps(Properties someProps) {
        this.someProps = someProps;
    }

    public String execute() {
        System.out.println("moduleName=" + moduleName);
        System.out.println("pageSize=" + pageSize);
        System.out.println("username=" + username);
        System.out.println("password=" + password);
        System.out.println("---List信息如下---");

        for (String s : someList) {
            System.out.println(s);
        }
        System.out.println("---Set信息如下---");
        for (String s : someSet) {
            System.out.println(s);
        }
        System.out.println("---Map信息如下---");
        Set<String> keys = someMap.keySet();
        for (String key : keys) {
            System.out.println(key + "=" + someMap.get(key));
        }
        System.out.println("---Properties信息如下---");
        Set<Object> keys1 = someProps.keySet();
        for (Object key : keys1) {
            System.out.println(key + "="
                    + someProps.getProperty(key.toString()));
        }

        return "success";
    }

}

Test1，Test2的完整代码如下：

package com.souvc.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.souvc.bean.MessageBean;

public class TestCase {

    @Test
    public void test1() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        System.out.println(ac);

        MessageBean messagebean = ac.getBean("messagebean", MessageBean.class);
        System.out.println(messagebean.toString());
        messagebean.execute();
    }

    @Test
    public void test2() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        MessageBean bean = ac.getBean("messagebean2", MessageBean.class);
        bean.execute();
    }
}

applicationContext.xml完整代码如下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd">



    <!-- 加载properties文件为bean-->
    <util:properties id="jdbcProperties"
        location="classpath:db.properties" />


    <bean id="messagebean" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="测试基本属性的注入"></property>
        <property name="pageSize" value="5"></property>
        <!-- 表达式注入 
            <property name="username" value="daliu_it"></property>-->
        <property name="username" value="#{jdbcProperties.user}"></property>
        <property name="password" >
        <null/>
        </property>
        <property name="someList">
            <list>
                <value>北京</value>
                <value>上海</value>
                <value>广州</value>
            </list>
        </property>
        <property name="someSet">
            <set>
                <value>James Gosling</value>
                <value>Martin fowler</value>
                <value>Larry Ellision</value>
            </set>
        </property>
        <property name="someMap">
            <map>
                <entry key="1001" value="Java语言基础"></entry>
                <entry key="1002" value="Java Web基础"></entry>
                <entry key="1003" value="Spring使用基础"></entry>
            </map>
        </property>
        <property name="someProps">
            <props>
                <prop key="username">root</prop>
                <prop key="password">1234</prop>
            </props>
        </property>
    </bean>


    <!-- 定义集合Bean -->
    <util:list id="oneList">
        <value>Tom</value>
        <value>Andy</value>
    </util:list>
    <util:set id="oneSet">
        <value>James Gosling</value>
        <value>Martin fowler</value>
    </util:set>
    <util:map id="oneMap">
        <entry key="1001" value="Java语言基础"></entry>
        <entry key="1002" value="Java Web基础"></entry>
    </util:map>
    <util:properties id="oneProps">
        <prop key="username">root</prop>
        <prop key="password">1234</prop>
    </util:properties>



    <!-- 引用方式注入集合属性 -->
    <bean id="messagebean2" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="资费管理"></property>
        <property name="pageSize" value="5"></property>
        <property name="username" value="andy"></property>
        <property name="password" value="123"></property>

        <!-- 引用方式注入集合属性 -->
        <property name="someList" ref="oneList" />
        <property name="someSet" ref="oneSet" />
        <property name="someMap" ref="oneMap" />
        <property name="someProps" ref="oneProps" />
    </bean>
</beans>

源码如下：http://yunpan.cn/cQVU3sLcMzXGC  访问密码 daf3

2 测试Spring自动组件扫描方式

2.1 问题

如何使用组件扫描的方式和"注解标记"配合获取容器中的ExampleBean对象。

2.2 方案

使用组件扫描，首先需要在XML配置中指定扫描类路径，配置代码如下：

 

    <context:component-scan 
                  base-package="com.souvc"/> 

上述配置，容器实例化时会自动扫描com.souvc 包及其子包下所有组件类。

指定扫描类路径后，并不是该路径下所有组件类都扫描到Spring容器的，只有在组件类定义前面有以下注解标记时，才会扫描到Spring容器。

@Component  泛指组件，当组件不好归类的时候，我们可以使用这个注解进行标注。

@Name 通用注解

@Service  业务层组件注解， 用于标注业务层组件

@Repository  持久层组件注解，用于标注数据访问组件，即DAO组件

@Controller  控制层组件注解，用于标注控制层组件（如struts中的action）

2.3 步骤

步骤一：新建类ExampleBean

新建类ExampleBean，在该类前使用通用组件注解“@Component”，表明ExampleBean为可被扫描的组件，代码如下所示：

package com.souvc.bean;

import org.springframework.stereotype.Component;

@Component
public class ExampleBean {

    public ExampleBean() {
        System.out.println("实例化ExampleBean");
    }

    public void execute() {
        System.out.println("执行ExampleBean处理");
    }
}

 

步骤二： 修改applicationContext.xml

修改applicationContext.xml，使容器实例化时自动扫描org.tarena包及其子包下所有组件类

 

<!-- 组件扫描 -->
    <context:component-scan base-package="com.souvc" />

步骤三： 新建方法Test3

@Test
    public void test3() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        ExampleBean bean = ac.getBean("exampleBean", ExampleBean.class);
        bean.execute();
    }

运行Test3方法，控制台输出结果：

实例化ExampleBean
执行ExampleBean处理

控制台输出上述结果，说明Spring会自动使用组件扫描的方式创建ExampleBean实例, 并且Test3中获取到了这个ExampleBean对象。

2.4 完整代码

ExampleBean类的完整代码如下所示：

package com.souvc.bean;

import org.springframework.stereotype.Component;

@Component
public class ExampleBean {

    public ExampleBean() {
        System.out.println("实例化ExampleBean");
    }

    public void execute() {
        System.out.println("执行ExampleBean处理");
    }
}

TestCase 类的完整代码如下所示：

package com.souvc.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.souvc.bean.ExampleBean;
import com.souvc.bean.MessageBean;

public class TestCase {

    @Test
    public void test1() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        System.out.println(ac);

        MessageBean messagebean = ac.getBean("messagebean", MessageBean.class);
        System.out.println(messagebean.toString());
        messagebean.execute();
    }

    @Test
    public void test2() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        MessageBean bean = ac.getBean("messagebean2", MessageBean.class);
        bean.execute();
    }

    @Test
    public void test3() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        ExampleBean bean = ac.getBean("exampleBean", ExampleBean.class);
        bean.execute();
    }
}

applicationContext.xml文件的完整代码如下所示：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd">



    <!-- 加载properties文件为bean-->
    <util:properties id="jdbcProperties"
        location="classpath:db.properties" />


    <bean id="messagebean" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="测试基本属性的注入"></property>
        <property name="pageSize" value="5"></property>
        <!-- 表达式注入 
            <property name="username" value="daliu_it"></property>-->
        <property name="username" value="#{jdbcProperties.user}"></property>
        <property name="password">
            <null />
        </property>
        <property name="someList">
            <list>
                <value>北京</value>
                <value>上海</value>
                <value>广州</value>
            </list>
        </property>
        <property name="someSet">
            <set>
                <value>James Gosling</value>
                <value>Martin fowler</value>
                <value>Larry Ellision</value>
            </set>
        </property>
        <property name="someMap">
            <map>
                <entry key="1001" value="Java语言基础"></entry>
                <entry key="1002" value="Java Web基础"></entry>
                <entry key="1003" value="Spring使用基础"></entry>
            </map>
        </property>
        <property name="someProps">
            <props>
                <prop key="username">root</prop>
                <prop key="password">1234</prop>
            </props>
        </property>
    </bean>


    <!-- 定义集合Bean -->
    <util:list id="oneList">
        <value>Tom</value>
        <value>Andy</value>
    </util:list>
    <util:set id="oneSet">
        <value>James Gosling</value>
        <value>Martin fowler</value>
    </util:set>
    <util:map id="oneMap">
        <entry key="1001" value="Java语言基础"></entry>
        <entry key="1002" value="Java Web基础"></entry>
    </util:map>
    <util:properties id="oneProps">
        <prop key="username">root</prop>
        <prop key="password">1234</prop>
    </util:properties>



    <!-- 引用方式注入集合属性 -->
    <bean id="messagebean2" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="资费管理"></property>
        <property name="pageSize" value="5"></property>
        <property name="username" value="andy"></property>
        <property name="password" value="123"></property>

        <!-- 引用方式注入集合属性 -->
        <property name="someList" ref="oneList" />
        <property name="someSet" ref="oneSet" />
        <property name="someMap" ref="oneMap" />
        <property name="someProps" ref="oneProps" />
    </bean>


    <!-- 组件扫描 -->
    <context:component-scan base-package="com.souvc" />


</beans>

3 如何控制ExampleBean实例化方式

3.1 问题

使用组件扫描的方式，重构如何控制ExampleBean实例化为单例或非单例模式。

3.2 方案

1. 通常受Spring管理的组件，默认的作用域是"singleton"。如果需要其他的作用域可以使用@Scope注解，只要在注解中提供作用域的名称即可，代码如下：

    @Component
    @Scope("singleton")
    public class ExampleBean {
       ...
        }

2. @PostConstruct和@PreDestroy注解标记分别用于指定初始化和销毁回调方法，代码如下：

    public class ExampleBean { 
          @PostConstruct 
          public void init() {
                //初始化回调方法
          } 
          
          @PreDestroy 
          public void destroy() { 
                 //销毁回调方法
           }
     }

 

3.3 步骤

步骤一：Bean对象的创建模式

1． 修改ExampleBean，使用prototype模式创建 ExampleBean 对象，修改的代码：

package com.souvc.bean;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component
@Scope("prototype")
public class ExampleBean {

    public ExampleBean() {
        System.out.println("实例化ExampleBean");
    }

//    public void execute() {
//        System.out.println("执行ExampleBean处理");
//    }
//
//    @PostConstruct
//    public void init() {
//        System.out.println("初始化ExampleBean对象");
//    }
//
//    @PreDestroy
//    public void destroy() {
//        System.out.println("销毁ExampleBean对象");
//    }
}

2． 新建类Test4在该类中创建两个ExampleBean对象，通过比较操作符==进行比较，代码如图-19所示：

    @Test
    public void test4() {
        String conf = "applicationContext.xml";
        AbstractApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        ExampleBean bean1 = ac.getBean("exampleBean", ExampleBean.class);
        ExampleBean bean2 = ac.getBean("exampleBean", ExampleBean.class);
        System.out.println(bean1 == bean2);
        ac.close();
    }

3． 运行Test4，控制台输出结果如下：

实例化ExampleBean
实例化ExampleBean
false

通过前面的讲解，了解到默认情况下Spring容器是通过单例模式创建Bean对象的。通过本案例的运行结果，可以看出使用原型方式，调用了2次ExampleBean类的构造方法，说明创建了2个ExampleBean对象。

4. 如果想要使用单例模式创建对象，也可以使用注解的方式进行显示标注，修改ExampleBean类的代码所示：

package com.souvc.bean;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component
//@Scope("prototype")
@Scope("singleton")
public class ExampleBean {

    public ExampleBean() {
        System.out.println("实例化ExampleBean");
    }

//    public void execute() {
//        System.out.println("执行ExampleBean处理");
//    }
//
//    @PostConstruct
//    public void init() {
//        System.out.println("初始化ExampleBean对象");
//    }
//
//    @PreDestroy
//    public void destroy() {
//        System.out.println("销毁ExampleBean对象");
//    }
}

5． 再次运行Test4，控制台输出结果如下：

实例化ExampleBean
true

 

上述运行结果可以看得出，两个ExampleBean对象，通过比较操作符“ ==”进行比较的输出结果为true，说明Spring容器是通过单例模式创建Bean对象的。

步骤二：Bean对象的初始化和销毁

1. 修改ExampleBean类，加入方法init和方法destroy，并使用注解“@PostConstruct”和注解“@PreDestroy”指定init为初始化的回调方法、destroy为销毁的回调方法，代码如下所示：

package com.souvc.bean;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component
//@Scope("prototype")
@Scope("singleton")
public class ExampleBean {

    public ExampleBean() {
        System.out.println("实例化ExampleBean");
    }

    public void execute() {
        System.out.println("执行ExampleBean处理");
    }

    @PostConstruct
    public void init() {
        System.out.println("初始化ExampleBean对象");
    }

    @PreDestroy
    public void destroy() {
        System.out.println("销毁ExampleBean对象");
    }
}

2.运行Test4类，控制台输出结果所示：

实例化ExampleBean
初始化ExampleBean对象
true
2015-6-17 14:26:05 org.springframework.context.support.AbstractApplicationContext doClose
信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@45b9ce4b: startup date [Wed Jun 17 14:26:04 CST 2015]; root of context hierarchy
2015-6-17 14:26:05 org.springframework.beans.factory.support.DefaultSingletonBeanRegistry destroySingletons
信息: Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@36f0b7f8: defining beans [jdbcProperties,messagebean,oneList,oneSet,oneMap,oneProps,messagebean2,exampleBean,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor]; root of factory hierarchy
销毁ExampleBean对象

控制台输出了“初始化ExampleBean对象”和“销毁ExampleBean对象”，说明使用组件扫描的方式为ExampleBean类添加初始化和销毁的回调方法成功。

3.4 完整代码

ExampleBean类的完整代码如下所示：

package com.souvc.bean;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component
//@Scope("prototype")
@Scope("singleton")
public class ExampleBean {

    public ExampleBean() {
        System.out.println("实例化ExampleBean");
    }

    public void execute() {
        System.out.println("执行ExampleBean处理");
    }

    @PostConstruct
    public void init() {
        System.out.println("初始化ExampleBean对象");
    }

    @PreDestroy
    public void destroy() {
        System.out.println("销毁ExampleBean对象");
    }
}

 

Test4类的完整代码如下所示：

package com.souvc.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.souvc.bean.ExampleBean;
import com.souvc.bean.MessageBean;

public class TestCase {

    @Test
    public void test1() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        System.out.println(ac);

        MessageBean messagebean = ac.getBean("messagebean", MessageBean.class);
        System.out.println(messagebean.toString());
        messagebean.execute();
    }

    @Test
    public void test2() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        MessageBean bean = ac.getBean("messagebean2", MessageBean.class);
        bean.execute();
    }

    @Test
    public void test3() {
        String conf = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        ExampleBean bean = ac.getBean("exampleBean", ExampleBean.class);
        //bean.execute();
    }

    @Test
    public void test4() {
        String conf = "applicationContext.xml";
        AbstractApplicationContext ac = new ClassPathXmlApplicationContext(conf);
        ExampleBean bean1 = ac.getBean("exampleBean", ExampleBean.class);
        ExampleBean bean2 = ac.getBean("exampleBean", ExampleBean.class);
        System.out.println(bean1 == bean2);
        ac.close();
    }

}

applicationContext.xml文件的完整代码与前一案例相同。

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd">



    <!-- 加载properties文件为bean-->
    <util:properties id="jdbcProperties"
        location="classpath:db.properties" />


    <bean id="messagebean" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="测试基本属性的注入"></property>
        <property name="pageSize" value="5"></property>
        <!-- 表达式注入 
            <property name="username" value="daliu_it"></property>-->
        <property name="username" value="#{jdbcProperties.user}"></property>
        <property name="password">
            <null />
        </property>
        <property name="someList">
            <list>
                <value>北京</value>
                <value>上海</value>
                <value>广州</value>
            </list>
        </property>
        <property name="someSet">
            <set>
                <value>James Gosling</value>
                <value>Martin fowler</value>
                <value>Larry Ellision</value>
            </set>
        </property>
        <property name="someMap">
            <map>
                <entry key="1001" value="Java语言基础"></entry>
                <entry key="1002" value="Java Web基础"></entry>
                <entry key="1003" value="Spring使用基础"></entry>
            </map>
        </property>
        <property name="someProps">
            <props>
                <prop key="username">root</prop>
                <prop key="password">1234</prop>
            </props>
        </property>
    </bean>


    <!-- 定义集合Bean -->
    <util:list id="oneList">
        <value>Tom</value>
        <value>Andy</value>
    </util:list>
    <util:set id="oneSet">
        <value>James Gosling</value>
        <value>Martin fowler</value>
    </util:set>
    <util:map id="oneMap">
        <entry key="1001" value="Java语言基础"></entry>
        <entry key="1002" value="Java Web基础"></entry>
    </util:map>
    <util:properties id="oneProps">
        <prop key="username">root</prop>
        <prop key="password">1234</prop>
    </util:properties>



    <!-- 引用方式注入集合属性 -->
    <bean id="messagebean2" class="com.souvc.bean.MessageBean">
        <property name="moduleName" value="资费管理"></property>
        <property name="pageSize" value="5"></property>
        <property name="username" value="andy"></property>
        <property name="password" value="123"></property>

        <!-- 引用方式注入集合属性 -->
        <property name="someList" ref="oneList" />
        <property name="someSet" ref="oneSet" />
        <property name="someMap" ref="oneMap" />
        <property name="someProps" ref="oneProps" />
    </bean>


    <!-- 组件扫描 -->
    <context:component-scan base-package="com.souvc" />


</beans>

本文作者：souvc

本文出处：http://www.cnblogs.com/liuhongfeng/p/4582664.html