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();
}
}