Bean的实例化--静态工厂

1，创建实体类User

package com.songyan.demo1;

/**
 * 要创建的对象类
 * @author sy
 *
 */
public class User {
private String name;
private int age ;
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public int getAge() {
    return age;
}
public void setAge(int age) {
    this.age = age;
}

}

2，创建生产对象的工厂类

改工厂类必须有一个静态的返回值为“要生产的对象的类型”

package com.songyan.staticfactory;

import com.songyan.demo1.User;
/**
 * 创建User对象的工厂类
 * @author sy
 *
 */
public class UserFactory {
    /**
     * 该方法必须是static的
     * @return 工厂要创建的对像
     */
public static User createUser()
{
    return new User();
}
}

3，配置bean对象

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd ">
    
    <!--通过构造函数创建对象  -->
    <bean id="userid" class="com.songyan.demo1.User"></bean>
    
    <!--通过静态工厂创建对象  -->
    <!--通过 com.songyan.staticfactory.UserFactory类中的createUser方法创建名为user2的对象 -->
    <bean name="user2" class="com.songyan.staticfactory.UserFactory" factory-method="createUser"></bean>
</beans>

4，测试类

package com.songyan.Test;

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

import com.songyan.demo1.User;

public class Client {
public static void main(String[] args) {
    ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");
    /*User user=(User)applicationContext.getBean("userid");
    System.out.println(user);*/
    User user2=(User)applicationContext.getBean("user2");
    System.out.println(user2);
    
}
}

5，结果