spring

spring是一个容器框架，贯穿于web层、service层、DAO层、持久层；

DI和IOC两个概念

第一个spring的例子

1、写一个service类

UserService类

package com.service;

public class UserService {
private String name;
private Info info;
public Info getInfo() {
    return info;
}

public void setInfo(Info info) {
    this.info = info;
}

public String getName() {
    return name;
}

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

public void  say(){
    System.out.println("第一个spring"+name);
    info.showInfo();
}

}

被依赖的类Info.java(可选)

package com.service;

public class Info {
private String name;
private String email;
private int age;
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public String getEmail() {
    return email;
}
public void setEmail(String email) {
    this.email = email;
}
public int getAge() {
    return age;
}
public void setAge(int age) {
    this.age = age;
}

public void showInfo(){
    System.out.println(name+"的邮箱是:"+email+" 年龄是："+age);
    
}

}

2、引入jar包，spring.jar和common Logging.jar(最小要求),写ApplicationContext.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<beans 
xmlns="http://www.springframework.org/schema/beans" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd"> 
<bean id="userService" class="com.service.UserService">
<property name="name">
<value>邹腾</value>
</property>
<property name="info" ref="info"/>
</bean>
<bean id="info" class="com.service.Info">
<property name="name" value="孙中山"/>
<property name="age" value="18"/>
<property name="email" value="yql@sina.cn"></property>
</bean>
</beans>

3、测试类Test.java

package com.test;


import com.service.UserService;
import com.util.ApplicationContextUtil;

public class Test {


    public static void main(String[] args) {
        // TODO Auto-generated method stub
        /*UserService userservice = new UserService();
        userservice.setName("邹腾");
        userservice.say();*/
        
    /*    ApplicationContext ac= new ClassPathXmlApplicationContext("ApplicationContext.xml");
         UserService us=(UserService) ac.getBean("userService");
         us.say();*/
       
    /*    Info info=new Info();
        info.setAge(18);
        info.setName("邹腾");
        info.setEmail("zouteng@sina.cn");
        info.showInfo();*/
    /*    ApplicationContext ac=new ClassPathXmlApplicationContext("ApplicationContext.xml");
        Info info=(Info) ac.getBean("info");
        info.showInfo();*/
        
((UserService)ApplicationContextUtil.getApplicationContext().getBean("userService")).say();
    }

}

工具类，保证ApplicationContext是单态的

package com.util;

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

public class ApplicationContextUtil {
private static ApplicationContext ac=null;
private ApplicationContextUtil(){
    
}
    static {
        ac=new ClassPathXmlApplicationContext("ApplicationContext.xml");
    }
    public static ApplicationContext getApplicationContext(){
        return ac;
    }
    
}