spring之注解

步骤1：修改applicationContext.xml

1 添加<context:annotation-config/>

表示告诉spring要用注解的方式进行配置

2 注入对象的21行注释掉，这个行为在后面将使用注解来完成

<?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:annotation-config/>
    <bean name="c" class="com.how2java.pojo.Category">
        <property name="name" value="category 1" />
    </bean>
    <bean name="p" class="com.how2java.pojo.Product">
        <property name="name" value="product1" />
<!--         <property name="category" ref="c" /> -->
    </bean>
  
</beans>

步骤2：@Autowired

在Product.java的category属性前加上@Autowired注解

package com.how2java.pojo;
 
import org.springframework.beans.factory.annotation.Autowired;
 
public class Product {
 
    private int id;
    private String name;
    @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;
    }
 
    public void setCategory(Category category) {
        this.category = category;
    }
}

步骤3：运行测试

package com.how2java.test;

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

import com.how2java.pojo.Product;

public class TestSpring {

	public static void main(String[] args) {
		ApplicationContext context = new ClassPathXmlApplicationContext(new String[] { "applicationContext.xml" });
		Product p = (Product) context.getBean("p");
		System.out.println(p.getName());
		System.out.println(p.getCategory().getName());
	}
}

步骤4： @Autowired的位置 

除了前面的在属性前加上@Autowired这种方式外，也可以在setCategory方法前加上@Autowired，这样来达到相同的效果

package com.how2java.pojo;
 
import org.springframework.beans.factory.annotation.Autowired;
 
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;
    }
    @Autowired
    public void setCategory(Category category) {
        this.category = category;
    }
}