1.Dao

package com.leo.dao;import com.leo.pojo.User;import java.util.List;public interface UserDao {// 查询全部用户List<User> getUserList();// 根据id查询用户User getUserById(int id);// 增加用户int addUser(User user);// 修改用户int updateUser(User user);// 删除用户int deleteUser(int id);
}

2.UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.leo.dao.UserDao"><select id="getUserList" resultType="com.leo.pojo.User">select * from mybatis.user;</select><select id="getUserById" resultType="com.leo.pojo.User" parameterType="int">select * from mybatis.user where id = #{id};</select><insert id="addUser" parameterType="com.leo.pojo.User">insert into mybatis.user(id, name, pwd) values(#{id},#{name},#{pwd});</insert><update id="updateUser" parameterType="com.leo.pojo.User">update mybatis.user set name=#{name},pwd=#{pwd} where id=#{id};</update><delete id="deleteUser" parameterType="int">delete from mybatis.user where id = #{id}</delete>
</mapper>

3.测试代码

package com.leo.dao;import com.leo.pojo.User;
import com.leo.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;import java.util.List;public class UserDaoTest {@Testpublic void test() {// 获取sqlSession对象SqlSession sqlSession = MybatisUtils.getSqlSession();try {UserDao userDao = sqlSession.getMapper(UserDao.class);List<User> userList = userDao.getUserList();for (User user : userList) {System.out.println(user);}} catch (Exception e) {e.printStackTrace();} finally {// 关闭sqlSessionsqlSession.close();}}@Testpublic void getUserById() {SqlSession sqlSession = MybatisUtils.getSqlSession();UserDao mapper = sqlSession.getMapper(UserDao.class);User user = mapper.getUserById(1);System.out.println(user);sqlSession.close();}@Testpublic void addUser() {SqlSession sqlSession = MybatisUtils.getSqlSession();UserDao mapper = sqlSession.getMapper(UserDao.class);int res = mapper.addUser(new User(4, "zhaoliu", "1688888"));if (res > 0) {System.out.println("插入成功");}// 提交事务sqlSession.commit();sqlSession.close();}@Testpublic void updateUser() {SqlSession sqlSession = MybatisUtils.getSqlSession();UserDao mapper = sqlSession.getMapper(UserDao.class);int res = mapper.updateUser(new User(4, "zhaoliu123", "123"));if (res > 0) {System.out.println("更新成功");}sqlSession.commit();sqlSession.close();}@Testpublic void deleteUser() {SqlSession sqlSession = MybatisUtils.getSqlSession();UserDao mapper = sqlSession.getMapper(UserDao.class);int i = mapper.deleteUser(4);if (i > 0) {System.out.println("删除成功");}sqlSession.commit();sqlSession.close();}
}

4.执行