Spring为某个属性注入值或为某个方法的返回值

项目中用到需要初始化一些数据，Spring提供了filed的值注入和method的返回值注入。

一、Field值的注入                                                                                           

     filed值注入需要使用org.springframework.beans.factory.config.FieldRetrievingFactoryBean来获取类的静态变量。

例如，我们通常在接口中定义常量：

package com.wy.inject;

/**
 * 
 * @author wy
 *
 */
public interface Fruit {
	public String APPLE = "苹果";
	public String ORANGE = "桔子";
}

 下面利用FieldRetrievingFactoryBean获取CarBandType接口中定义的常量，并注入到某个bean的属性中：

<?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:task="http://www.springframework.org/schema/task"
	xsi:schemaLocation="http://www.springframework.org/schema/context 
	   					   http://www.springframework.org/schema/context/spring-context-3.1.xsd  
	   					   http://www.springframework.org/schema/beans 
	   					   http://www.springframework.org/schema/beans/spring-beans-3.1.xsd  
	   					   http://www.springframework.org/schema/task 
	   					   http://www.springframework.org/schema/task/spring-task-3.1.xsd">
	<!-- 1、通过注入属性 
	<bean id="appleBean" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean">
		<property name="staticField" value="com.wy.inject.Fruit.APPLE" />
	</bean>
	<bean id="apple" class="com.wy.inject.Apple">
		<property name="name" ref="appleBean" />
	</bean>-->

 Spring还允许用户用常量的全限定名作为FieldRetrievingFactoryBean的id，其效果和通过配置staticField属性是一样的：

<!-- 2、通过全限量名称
	<bean id="com.wy.inject.Fruit.APPLE" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean">
	</bean>
	<bean id="apple" class="com.wy.inject.Apple">
		<property name="name" ref="com.wy.inject.Fruit.APPLE" />
	</bean> -->

 当然，也可以直接将FieldRetrievingFactoryBean以内置bean的方式对属性进行赋值，这样在配置上更紧凑一些：

<!-- 3、通过内置Bean的方式 
	<bean id="apple" class="com.wy.inject.Apple">
		<property name="name">
			<bean id="com.wy.inject.Fruit.APPLE" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean"/>
		</property>
	</bean>-->

 

二、Method返回值的注入
Method返回值的注入需要使用MethodInvokingFactoryBean来完成。

在xml配置中，需要设定targetObject和targetMethod来指定目标bean和方法。如果使用静态方法，则需要指定targetClass和targetMethod。

1、非静态方法配置文件如下：

<!-- 1、Method返回值的注入
	<bean id="apple" class="com.wy.inject.Apple">
		<property name="name">
			<bean
				class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
				<property name="targetObject">
					<ref local="cons" />
				</property>
				<property name="targetMethod">
					<value>getAPPLE</value>
				</property>
			</bean>
		</property>
	</bean>
	<bean id="cons" class="com.wy.inject.Cons" /> -->

 2、静态方法的配置

<!-- 2、静态方法返回值的注入 -->
	<bean id="banna" class="com.wy.inject.Banna">
	  <property name="name">
	    <bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
	      <property name="targetClass">
	        <value>com.wy.inject.Cons</value>
	      </property>
	      <property name="targetMethod">
	        <!-- getBann必须是静态方法 -->
	        <value>getBann</value>
	      </property>
	    </bean>
	  </property>
	</bean>

 涉及到的类：

Apple.java

package com.wy.inject;

/**
 * 
 * @author wy
 * 
 */

public class Apple {
	String name = null;
	String price = null;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getPrice() {
		return price;
	}

	public void setPrice(String price) {
		this.price = price;
	}

}

 Cons.java

package com.wy.inject;

/**
 * 
 * @author wy
 * 
 */
public class Cons {
	public String APPLE = "苹果";
	public String ORANGE = "桔子";
	public static String Bann = "香蕉";

	public String getAPPLE() {
		return APPLE;
	}

	public void setAPPLE(String aPPLE) {
		APPLE = aPPLE;
	}

	public String getORANGE() {
		return ORANGE;
	}

	public void setORANGE(String oRANGE) {
		ORANGE = oRANGE;
	}
	
	
	
	public static String getBann() {
		return Bann;
	}

	public static void setBann(String bann) {
		Bann = bann;
	}

}

 Banna.java

package com.wy.inject;

/**
 * 
 * @author wy
 *
 */
public class Banna {
	String name = null;
	String price = null;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getPrice() {
		return price;
	}

	public void setPrice(String price) {
		this.price = price;
	}
}

 三、测试例子

package com.wy.inject;

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

public class InjectTest {
	public Apple apple = null;
	public Banna banna = null;
	public InjectTest() {
		ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml"); 
//		apple = (Apple)context.getBean("apple");
		banna = (Banna)context.getBean("banna");
	}
	
	public void name(){
//		System.out.println("Fruit name=" + apple.getName());
		System.out.println("Fruit name=" + banna.getName());
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		new InjectTest().name();
	}

}