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1. dao层代码

import com.baidu.pojo.User;import org.apache.ibatis.annotations.*;import java.util.List;public interface UserDao {
       //查询所有用户    @Select("select * from user")    List
   
     getUserList();    @Select("select * from user where id = #{id}")    User getUserById(@Param("id") int id);    @Insert("insert into user(id,name,pwd) values (#{id},#{name},#{pwd})")    int insert(User user);    @Delete("delete from user where id = #{id}")    int deleteUserById(@Param("id") int id);    @Update("update user set name = #{name},pwd = #{pwd} where id = #{id}")    int updateUser(User user);}
   

2. 工具类

package com.baidu.utils;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 java.io.IOException;import java.io.InputStream;//mybatis的工具类，重复的代码的提纯public class MyBatisUtils {
       //类变量不需要设置默认值；    private static SqlSessionFactory sqlSessionFactory;    static {
           //在maven中，所有的资源文件一般都放在resources目录下，我们可以直接拿到。        InputStream inputStream = null;        try {
               String resource = "mybatis-config.xml";            inputStream = Resources.getResourceAsStream(resource);            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);        } catch (IOException e) {
               e.printStackTrace();        }finally {
               if (inputStream != null){
                   try {
                       inputStream.close();                } catch (IOException e) {
                       e.printStackTrace();                }            }        }    }    //设置事务自动提交    public static SqlSession getSqlSession(){
           return sqlSessionFactory.openSession(true);    }}

3. 测试类

package com.baidu.dao;import com.baidu.pojo.User;import com.baidu.utils.MyBatisUtils;import org.apache.ibatis.session.SqlSession;import org.junit.Test;import java.util.List;public class UserDaoTest {
       @Test    public void getUserList(){
           SqlSession sqlSession = MyBatisUtils.getSqlSession();        UserDao mapper = sqlSession.getMapper(UserDao.class);        List
   
     userList = mapper.getUserList();        for (User user : userList) {
               System.out.println(user);        }        sqlSession.close();    }    @Test    public void getUserById(){
           SqlSession sqlSession = MyBatisUtils.getSqlSession();        UserDao mapper = sqlSession.getMapper(UserDao.class);        User user =  mapper.getUserById(1);        sqlSession.close();               System.out.println(user);    }    @Test    public void insert(){
           SqlSession sqlSession = MyBatisUtils.getSqlSession();        UserDao mapper = sqlSession.getMapper(UserDao.class);        int i = mapper.insert(new User(9, "辛卫东", "12456"));        sqlSession.close();        System.out.println(i);    }    @Test    public void deleteById(){
           SqlSession sqlSession = MyBatisUtils.getSqlSession();        UserDao mapper = sqlSession.getMapper(UserDao.class);        int i = mapper.deleteUserById(9);        sqlSession.close();        System.out.println(i);    }    @Test    public void updateById(){
           SqlSession sqlSession = MyBatisUtils.getSqlSession();        UserDao mapper = sqlSession.getMapper(UserDao.class);        int i = mapper.updateUser(new User(8,"xwd","789460"));        sqlSession.close();        System.out.println(i);    }}
   

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