Spring的基本业务流程与类的多实现

Dear 丶 2022-01-16 14:17 127阅读 0赞

目录结构：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NjUxMjY3_size_16_color_FFFFFF_t_70]applicationContext.xml

<?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:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">
    
        <context:component-scan base-package="com.xbj"/>
    </beans>

UserCoutroller.java

package com.xbj.controller;
    
    import com.xbj.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Qualifier;
    import org.springframework.stereotype.Controller;
    
    /** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
    @Controller
    public class UserCoutroller { 
        /* * Autowired:注入的是接口的实现类 * 如果没有实现类 无法注入 * 如果有多个实现类 也无法自动注入，需要通过Qualifier 指定ID * ID的默认值是 类名的首字母小写 * */
        @Autowired
        @Qualifier("userServiceImpl")
        private UserService userService;
    
        public String addUser() { 
            userService.addUser();
            return "SUCCESS";
        }
    }

UserDaoImpl.java

package com.xbj.dao.impl;
    import com.xbj.dao.UserDao;
    import org.springframework.stereotype.Repository;
    /** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
    @Repository
    public class UserDaoImpl implements UserDao { 
    
        public void addUser() { 
            System.out.println("addUser");
        }
    }

UserDao.java

package com.xbj.dao;
    /** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
    public interface UserDao { 
         void addUser();
    }

UserServiceImpl.java

package com.xbj.service.impl;
    
    import com.xbj.dao.UserDao;
    import com.xbj.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.context.annotation.Scope;
    import org.springframework.stereotype.Service;
    
    import javax.annotation.PostConstruct;
    import javax.annotation.PreDestroy;
    
    /** * @Author:晓宇码匠 * @Date：2019/6/15 0015 * * @Scope如果是设为多例，在方法结束时，不会进行销毁，而是变成休眠态 * 反之，单例就会执行销毁方法 */
    @Service
    @Scope(value = "prototype")//将实现类设置成多例的 、 不设默认是单例的singleton
    public class UserServiceImpl implements UserService { 
    
        @Autowired
        private UserDao userDao;
    
        public void addUser() { 
            userDao.addUser();
        }
    
        @PostConstruct
        public void init(){ 
            //初始化
            System.out.println("初始化");
        }
        @PreDestroy
        public void dest(){ 
            //销毁
            System.out.println("销毁");
        }
    }

UserServiceImpl2.java

package com.xbj.service.impl;
    
            import com.xbj.dao.UserDao;
            import com.xbj.service.UserService;
            import org.springframework.beans.factory.annotation.Autowired;
            import org.springframework.context.annotation.Scope;
            import org.springframework.stereotype.Service;
    
            import javax.annotation.PostConstruct;
            import javax.annotation.PreDestroy;
    
    /** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
    @Service
    @Scope(value = "prototype")//将实现类设置成多例的 、 不设默认是单例的singleton
    public class UserServiceImpl2 implements UserService { 
    
        @Autowired
        private UserDao userDao;
    
        public void addUser() { 
            userDao.addUser();
        }
    
    }

UserService.java

package com.xbj.service;
    
    /** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
    public interface UserService { 
        void addUser();
    }

test.java

import com.xbj.controller.UserCoutroller;
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    
    /** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(locations = { "classpath:applicationContext.xml"})
    public class test { 
        @Autowired
        private  UserCoutroller userCoutroller;
        @Test
        public void t1(){ 
            System.out.println(userCoutroller.addUser());
        }
    }

单例，控制台输出：

初始化
    addUser
    SUCCESS
    销毁

多例，控制台输出：

初始化
    addUser
    SUCCESS

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NjUxMjY3_size_16_color_FFFFFF_t_70]: /images/20220114/c999b34040bc4ab2ab13a784ef2b5f5a.png