java|Mybatis------代理开发 mybatis|java

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【java|Mybatis------代理开发】什么是代理开发呢。
传统方式实现 DAO 层，需要写接口和实现类。采用 Mybatis 的代理开发方式实现 DAO 层的开发，只需要编写 Mapper 接口（相当于 Dao 接口），由 Mybatis 框架根据接口定义创建接口的动态代理对象

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第一个是对接数据库的，比如我的数据库有一个表是id + name。

package com.xuexi.domain; import java.io.Serializable; public class User implements Serializable{ private int id; private String name; public void setId(int id) { this.id = id; }public void setName(String name) { this.name = name; }public int getId() { return id; }public String getName() { return name; }@Override public String toString() { return "id: "+ id+" name:" + name; } }

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第二个就是mapper接口了。只需要编写 Mapper 接口（相当于 Dao 接口）

package com.xuexi.Mapper; import com.xuexi.domain.User; import java.util.List; public interface UserMapper { List selectedById(int id); public Integer saverUser(User user); publicInteger deleteUser(int id); }

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里面有查询，增加，和删除。
第三个很简单啦，Mybatis配置文件。

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第四个写mysql的地方

select * from users; select * from users where id = #{id}; insert into users (id,name) values(#{id},#{name}); delete from users where id = #{id};

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第五个不用说了吧，写测试的地方

import com.xuexi.Mapper.UserMapper; import com.xuexi.domain.User; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import org.junit.Test; import java.io.IOException; import java.io.InputStream; import java.util.List; public class Mytest{static SqlSession sqlSession; static {String resource = "mybatis-config.xml"; InputStream inputStream = null; try { inputStream = Resources.getResourceAsStream(resource); } catch (IOException e) { throw new RuntimeException(e); } SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); //2. 获取SqlSession对象，用它来执行sql sqlSession = sqlSessionFactory.openSession(); }@Test public void test() throws Exception { //获取路径 //3. 执行sql //List users = sqlSession.selectList("test.Querry"); //代理开发 UserMapper usermapper = sqlSession.getMapper(UserMapper.class); //UserMapper mapper = sqlSession.getMapper(UserMapper.class); List users = usermapper.selectedById(1); System.out.println(users); //4. 释放资源 sqlSession.close(); }@Test public void inserttest() throws Exception { UserMapper usermapper = sqlSession.getMapper(UserMapper.class); //UserMapper mapper = sqlSession.getMapper(UserMapper.class); User user1 = new User(); user1.setId(7); user1.setName("小青龙"); Integer success =usermapper.saverUser(user1); sqlSession.commit(); if(success <=0) { System.out.println("失败了！"); } else { System.out.println("成功了！"); } //4. 释放资源 sqlSession.close(); }@Test public void deletetest() throws Exception { UserMapper usermapper = sqlSession.getMapper(UserMapper.class); //UserMapper mapper = sqlSession.getMapper(UserMapper.class); Integer success =usermapper.deleteUser(7); sqlSession.commit(); if(success <=0) { System.out.println("失败了！"); } else { System.out.println("成功了！"); } //4. 释放资源 sqlSession.close(); }}