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10-Spring配置文件-详解4(factory,bean,method)

发布时间：2024-12-18 18:19:53编辑：雪饮阅读（）

bean除了能通过无参构造进行构建，还可以通过静态工厂来构建dao实例。
Spring Config配置文件
<bean id="userDao" class="com.factory.StaticFactory" factory-method="getUserDao"></bean>
静态工厂
package com.factory;
import com.dao.UserDao;
import com.dao.impl.UserDaoImpl;
public class StaticFactory {
    public static UserDao getUserDao(){
            return new UserDaoImpl();
    }
}
单元测试
import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test1 {
    @Test
    public void test1(){
        ClassPathXmlApplicationContext app=new ClassPathXmlApplicationContext("applicationContext.xml");
        app.getBean("userDao");
        app.close();
    }
}
当然也支持动态工厂来构建。则Spring Config配置如
<?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.xsd">
        <bean id="userDaoFactory" class="com.factory.DynamicFactory"></bean>
        <bean id="userDao" factory-bean="userDaoFactory" factory-method="getUserDao"></bean>

</beans>
动态工厂如：
package com.factory;

import com.dao.UserDao;
import com.dao.impl.UserDaoImpl;

public class DynamicFactory {
    public UserDao getUserDao(){
        return new UserDaoImpl();
    }
}
单元测试不用变。