写在前面：spring框架的火热不言而喻，为此学习spring是有必要的。热衷于实践的我更喜欢用案例来分析与理解。从今天开始，我们来走近spring，
希望通过这些简单的案例能够让我们对spring有个简单的了解，并达到入门水平。
准备材料：1.IDE：eclipse，
2.JDK：1.8，
3.JARS：spring核心包
学习目标：1.spring注入属性
2.spring注入对象
3.spring注解注入方式
一.spring注入属性
1.pojo实体类Category
package com.practice.pojo; public class Category { private int id; private String name; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
2.spring核心配置文件。applicationContext.xml
<?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:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> <!-- 配置第一个bean --> <bean id="c" class="com.practice.pojo.Category"> <property name="name" value="category1"></property> </bean> </beans>
3.编写测试类
package com.practice.test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import com.practice.pojo.Category; public class TestSpring { public static void main (String args[]){ ApplicationContext context=new ClassPathXmlApplicationContext(new String[]{"applicationContext.xml"}); Category c1=(Category)context.getBean("c"); System.out.println(c1.getName()); } }
4.运行结果
九月 24, 2019 1:59:05 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh 信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@2e5d6d97: startup date [Tue Sep 24 13:59:05 CST 2019]; root of context hierarchy 九月 24, 2019 1:59:05 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 信息: Loading XML bean definitions from class path resource [applicationContext.xml] category1
二.spring注入对象
1.pojo实体类Product
package com.practice.pojo; public class Product { private int id; private String name; private Category category; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Category getCategory() { return category; } public void setCategory(Category category) { this.category = category; } }
2.Spring核心配置文件。applicationContext.xml
<?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:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> <!-- 配置第一个bean --> <bean id="c" class="com.practice.pojo.Category"> <property name="name" value="category1"></property> </bean> <!-- 配置第二个bean --> <bean id="p" class="com.practice.pojo.Product"> <property name="category" ref="c"></property> </bean> </beans>
3.测试类
package com.practice.test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import com.practice.pojo.Product; public class TestSpring { public static void main (String args[]){ ApplicationContext context=new ClassPathXmlApplicationContext(new String[]{"applicationContext.xml"}); // Category c1=(Category)context.getBean("c"); // System.out.println(c1.getName()); Product p1=(Product)context.getBean("p"); System.out.println(p1.getCategory().getName()); } }
4.运行结果
九月 24, 2019 2:46:56 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh 信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@6433a2: startup date [Tue Sep 24 14:46:56 CST 2019]; root of context hierarchy 九月 24, 2019 2:46:57 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 信息: Loading XML bean definitions from class path resource [applicationContext.xml] category1
三.spring注解注入方式（注解属性对象）
1.对上面已经存在的文件进行修改，修改Spring核心配置文件。applicaitonContext.xml (红色部分是修改的部分)
<?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:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> <!-- 开放注解功能 --> <context:annotation-config></context:annotation-config> <!-- 配置第一个bean --> <bean id="c" class="com.practice.pojo.Category"> <property name="name" value="category1"></property> </bean> <!-- 配置第二个bean --> <bean id="p" class="com.practice.pojo.Product"> <!-- <property name="category" ref="c"></property>--> </bean> </beans>
2.Product实体类
package com.practice.pojo; import org.springframework.beans.factory.annotation.Autowired; public class Product { private int id; private String name; //这一行的下一行 " @Autowired " 可以换成 " @Resource(name="c")" @Autowired private Category category; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Category getCategory() { return category; } //如果上面的注解你都没用，那么你在下一行可以写上注解 “@Autowired" public void setCategory(Category category) { this.category = category; } } //以上三种注解方式都可以实现同样的预期结果。
3.运行结果
九月 24, 2019 2:46:56 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh 信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@6433a2: startup date [Tue Sep 24 14:46:56 CST 2019]; root of context hierarchy 九月 24, 2019 2:46:57 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 信息: Loading XML bean definitions from class path resource [applicationContext.xml] category1
四.spring注解注入方式（注解bean）
1.修改Spring配置文件applicaitonContext.xml。
<?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:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> <context:component-scan base-package="com.practice.pojo"></context:component-scan> </beans>
2.修改Product类
package com.practice.pojo; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; @Component("p") public class Product { private int id; private String name="product1"; //这一行的下一行 " @Autowired " 可以换成 " @Resource(name="c")" @Autowired private Category category; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Category getCategory() { return category; } //如果上面的注解你都没用，那么你在下一行可以写上注解 “@Autowired" public void setCategory(Category category) { this.category = category; } } //以上三种注解方式都可以实现同样的预期结果。
3.修改Category类
package com.practice.pojo; import org.springframework.stereotype.Component; @Component("c") public class Category { private int id; private String name="category1"; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
4.运行结果
九月 24, 2019 3:22:23 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh 信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@6433a2: startup date [Tue Sep 24 15:22:23 CST 2019]; root of context hierarchy 九月 24, 2019 3:22:24 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 信息: Loading XML bean definitions from class path resource [applicationContext.xml] category1
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-------------------------------------------分割线,以上我相信很容易看出异同，学习一个东西，首先是模仿，以后我会讲一讲我对控制反转和依赖注入的深入理解-------------------------------