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spring入门一

一、准备工作

下载Spring库

http://maven.springframework.org/release/org/springframework/spring/

二、新建web项目

其中：HelloProgram 为主程序，HelloWorldService 作为接口和两个实现类的中间类，依靠spring的注入，通过配置，决定service中运行的具体是哪个实现类。

三、具体代码

接口类HelloWorld

package com.yibai.spring.helloworld;

public interface HelloWorld {

    public void sayHello();
}

实现类SpringHelloWorld

package com.yibai.spring.helloworld.impl;

import com.yibai.spring.helloworld.HelloWorld;

public class SpringHelloWorld implements HelloWorld{

    @Override
    public void sayHello() {
        System.out.println("spring hello world");
    }

}

实现类StrutsHelloWorld

package com.yibai.spring.helloworld.impl;

import com.yibai.spring.helloworld.HelloWorld;

public class StrutsHelloWorld implements HelloWorld{

    @Override
    public void sayHello() {
        System.out.println("struts hello world");
    }

}

service类

package com.yibai.spring.helloworld;

public class HelloWorldService {

    private HelloWorld helloWorld;  //通过service bean中注入 不同的实现类，来实现不同的逻辑
    
    public HelloWorldService(){
        
    }

    public HelloWorld getHelloWorld() {
        return helloWorld;
    }

    public void setHelloWorld(HelloWorld helloWorld) {
        this.helloWorld = helloWorld;
    }
    
    
}

main类

package com.yibai.spring;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.yibai.spring.helloworld.HelloWorld;
import com.yibai.spring.helloworld.HelloWorldService;

public class HelloProgram {

    public static void main(String[] args) {
        
        // 创建上下文对象
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        
        HelloWorldService service = (HelloWorldService) context.getBean("helloWorldService");
        
        HelloWorld helloWorld = service.getHelloWorld();
        
        helloWorld.sayHello();
        
    }
}

四、web.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
    id="WebApp_ID" version="3.1">
    <display-name>spring01</display-name>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>

    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
    </welcome-file-list>
</web-app>

Spring配置

<?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:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">

    <bean id="springHelloWorld"
        class="com.yibai.spring.helloworld.impl.SpringHelloWorld">
    </bean>
    <bean id="strutsHelloWorld"
        class="com.yibai.spring.helloworld.impl.StrutsHelloWorld">
    </bean>

    <bean id="helloWorldService" class="com.yibai.spring.helloworld.HelloWorldService">
        <!-- 通过 ref属性，注入需要的bean，该属性会通过 set方法注入 -->
        <property name = "helloWorld" ref="strutsHelloWorld" />
    </bean>


</beans>