SPRING-HELLOWORLD 改写为构造注入

1.helloworld类增加构造方法

2.改写配置文件config.xml

3.测试程序testhelloworld.java

1.增加构造方法，MSG作为参数

package com.gc.action;

public class HelloWorld {

	public String msg=null;//该变量用来存储字符串
	
	//增加了一个构造方法
	public HelloWorld(String msg) {
		this.msg=msg;
	}
	
	//设定变量msg的set方法
	public void setMsg(String msg) {
		this.msg=msg;
	}
	
	//获取变量msg的get方法
	public String getMsg() {
		return this.msg;
	}
	
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
    <!--定义一个Bean-->
    <bean id="HelloWorld" class="com.gc.action.HelloWorld">
    <!--通过构造函数进行注入-->
    <constructor-arg index="0">
        <value>nihao</value>
    </constructor-arg>
    </bean>
</beans>

package com.gc.test;

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

import com.gc.action.HelloWorld;

public class TestHelloWorld {
    public static void main(String[] args)
    {
    	//通过ApplicationContext来获取Spring文件的配置
    	ApplicationContext actx=new FileSystemXmlApplicationContext("config.xml");
    
        //通过Bean的id来获取Bean
    	HelloWorld HelloWorld=(HelloWorld)actx.getBean("HelloWorld");
    	
    	//打印输出
    	System.out.println(HelloWorld.getMsg());
    }
}

nihao