spring入门基础

Spring入门—反射技术

无参数的

Java代码 

Class.forName(className).newInstance;
//有参数的
Class.forName(className).getDeclaredConstructor(String.class).newInstance(“黎明”);
//通过反射获取属性
Introspector.getBeanInfo(Person.class).getPropertyDescriptors()
//通过反射机制修改bean属性的值
Person person=(Person)Class.forName(className).getDeclaredConstructor(String.class).newInstance("黎明");
PropertyDescriptor[] ps = Introspector.getBeanInfo(Person.class).getPropertyDescriptors();
for(PropertyDescriptor p :ps){
System.out.println(p.getName());
if(p.getName().equals("name")){
Method setter=p.getWriteMethod();
if(setter!=null){
setter.setAccessible(true);//允许访问private属性
setter.invoke(person, "小燕子");

//通过反射机制修改bean字段的值
Field field=Person.class.getDeclaredField("name");
field.setAccessible(true);//允许访问private字段
field.set( person , "sss");



Class.forName(className).newInstance;
//有参数的
Class.forName(className).getDeclaredConstructor(String.class).newInstance(“黎明”);
//通过反射获取属性
Introspector.getBeanInfo(Person.class).getPropertyDescriptors()
//通过反射机制修改bean属性的值
Person person=(Person)Class.forName(className).getDeclaredConstructor(String.class).newInstance("黎明");
PropertyDescriptor[] ps = Introspector.getBeanInfo(Person.class).getPropertyDescriptors();
for(PropertyDescriptor p :ps){
System.out.println(p.getName());
if(p.getName().equals("name")){
Method setter=p.getWriteMethod();
if(setter!=null){
setter.setAccessible(true);//允许访问private属性
setter.invoke(person, "小燕子");

//通过反射机制修改bean字段的值
Field field=Person.class.getDeclaredField("name");
field.setAccessible(true);//允许访问private字段
field.set( person , "sss");

Spring提供了声明式的事务管理

软件的解耦合，不是硬编码

Spring 需要的jar

Dist\spring.jar

lib\jakarta-commons\commons-logging.jar

如果使用了切面编程(AOP),还需要下列jar文件

lib/aspectj/aspectjweaver.jar和aspectjrt.jar
lib/cglib/cglib-nodep-2.1_3.jar

如果使用了JSR-250中的注解,如@Resource/@PostConstruct/@PreDestroy,还需要下列jar文件

lib\j2ee\common-annotations.jar

配置文件beans.xml

Java代码

<?xml version="1.0" encoding="UTF-8"?>
t;beans xmlns="http://www.springframework.org/schema/beans"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://www.springframework.org/schema/beans
         http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

<bean id="xx" class="junit.test.Person" lazy-init="true">
</bean>
t;/beans>

  <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

  <bean id="xx" class="junit.test.Person" lazy-init="true">
  </bean>
</beans>

怎么启动spring容器Java代码 

ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
Person s = (Person)context.getBean("xx");


ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
Person s = (Person)context.getBean("xx");

默认bean是容器启动时实例化，只在容器中创建一次，spring中的对象一直存在容器中，是单例模式

表 3.4. Bean作用域

作用域       描述
singleton    在每个Spring IoC容器中一个bean定义对应一个对象实例。
prototype    一个bean定义对应多个对象实例。
request       在一次HTTP请求中，一个bean定义对应一个实例；即每次HTTP请求将会有各自的bean实例， 它们依据某个bean定义创建而成。该作用域仅在基于web的Spring ApplicationContext情形下有效。
session        在一个HTTP Session中，一个bean定义对应一个实例。该作用域仅在基于web的Spring ApplicationContext情形下有效。
global session     在一个全局的HTTP Session中，一个bean定义对应一个实例。典型情况下，仅在使用portlet context的时候有效。该作用域仅在基于web的Spring ApplicationContext情形下有效。

Spring入门—利用工厂方法创建bean

Java代码 

public class PersonFactory {
public static Person createPerson(){
    return new Person();
}
public Person createPerson2(){
    return new Person();
}

  public class PersonFactory {
 public static Person createPerson(){
  return new Person();
 }
 public Person createPerson2(){
  return new Person();
 }
}

Java代码 

//使用静态工厂方法实例化
<bean id="person" class="bean.PersonFactory" factory-method="createPerson"></bean>
使用实例工厂方法实例化
<bean id="personFactory" class="bean.PersonFactory"></bean>
 <bean id="person2" factory-bean="personFactory" factory-method="createPerson2"></bean>


//使用静态工厂方法实例化
<bean id="person" class="bean.PersonFactory" factory-method="createPerson"></bean>
使用实例工厂方法实例化
<bean id="personFactory" class="bean.PersonFactory"></bean>
 <bean id="person2" factory-bean="personFactory" factory-method="createPerson2"></bean>

Spring入门—依赖注入

Java代码 

public class Person {

    private Integer id;
    private String name="aa";
    private IDCard idcard;

    public IDCard getIdcard() {
        return idcard;
    }

    public void setIdcard(IDCard idcard) {
        this.idcard = idcard;
    }

    public Person(String name) {
        this.name = name;
    }

    public Person() {
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

}
public class IDCard {
    private String no;

    public String getNo() {
        return no;
    }

    public void setNo(String no) {
        this.no = no;
    }
}


public class Person {

 private Integer id;
 private String name="aa";
 private IDCard idcard;

 public IDCard getIdcard() {
  return idcard;
 }

 public void setIdcard(IDCard idcard) {
  this.idcard = idcard;
 }

 public Person(String name) {
  this.name = name;
 }

 public Person() {
 }
 public Integer getId() {
  return id;
 }
 public void setId(Integer id) {
  this.id = id;
 }
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }

}
public class IDCard {
 private String no;

 public String getNo() {
  return no;
 }

 public void setNo(String no) {
  this.no = no;
 }
}

第一种方法
Java代码

<bean id="xx" class="junit.test.Person" lazy-init="true">
<property name="idcard">
<bean class="junit.test.IDCard">
   <property name="no" value="9999"></property>
   </bean>
 </property>
</bean>

  <bean id="xx" class="junit.test.Person" lazy-init="true">
  <property name="idcard">
  <bean class="junit.test.IDCard">
     <property name="no" value="9999"></property>
     </bean>
   </property>
  </bean>

第二种方法

Java代码 

<bean id="aa" class="junit.test.IDCard">
<property name="no" value="88888888"></property>
</bean>
 <bean id="xx" class="junit.test.Person" lazy-init="true">
  <property name="idcard" ref="aa">
        </property>
  </bean>
<bean id="aa" class="junit.test.IDCard">
<property name="no" value="88888888"></property>
</bean>
<bean id="xx" class="junit.test.Person" lazy-init="true">
  <property name="idcard" ref="aa">
  </property>
  </bean>

为属性配置null值

Java代码 

<property name="name"><null/></property>


public class Person {
    private String name="ss";
public Person(){}
    public Person(String name) {
        this.name = name;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    public void say(){
        System.out.println("我说了");
    }
}

 <property name="name"><null/></property>


public class Person {
 private String name="ss";
public Person(){}
 public Person(String name) {
  this.name = name;
 }
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }

 public void say(){
  System.out.println("我说了");
 }
}

初始化bean执行say方法相当于测试单元的@BeforeClass

<bean id="xxx" class="bean.Person" scope="singleton" lazy-init="false" init-method="say">

集合依赖注入

Java代码 

<property name="lists">
         <list>
            <value>1111</value>
            <value>2222</value>
            <value>3333</value>
            <value>4444</value>
         </list>
</property>
for(String s : p.getLists){
            System.out.println(s);
        }
<property name="sets">
         <set>
            <value>TTT</value>
            <value>YYY</value>
          </set>
</property>
for(String s : p.getSets){
            System.out.println(s);
        }

<property name="maps">
      <map>
            <entry key="key1" value="value1"></entry>
            <entry key="key2" value="value2"></entry>
       </map>
</property>
for(String key : p.getMaps().keySet()){
            System.out.println(key+"="+ p. getMaps ().get(key));
        }
Properties 是注入
<property name="propers">
       <props>
            <prop key="proper1">value1</prop>
            <prop key="proper2">value2</prop>
       </props>
</property>
for(Object key : p.getPropers().keySet()){
            System.out.println(key+"="+ p.getPropers().get(key));
        }