Mybatis中的CRUD

Mybatis中的CRUD

Mybatis工具类

public class MybatisUtils {

    private static SqlSessionFactory sqlSessionFactory;

    static {
        try {
            // 从配置文件获取SqlSessionFactory
            String resource = "mybatis-config.xml";
            InputStream resourceAsStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
            resourceAsStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static SqlSession getSqlSession() {
        return sqlSessionFactory.openSession();
    }
}

接口

public interface UserMapper {
    List<User> selectAll();

    User selectById(int id);

    int insertUser(User user);

    int updateUser(User user);

    int deleteById(int id);
}

实现映射

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!--namespace 绑定一个对应的Dao/Mapper接口-->
<mapper namespace="com.base.dao.UserMapper">
    <!--id对应方法名-->
    <select id="selectAll" resultType="com.base.entity.User">
        select * from user;
    </select>

    <select id="selectById" resultType="com.base.entity.User" parameterType="int">
        select * from user where id = #{id};
    </select>

    <insert id="insertUser" parameterType="com.base.entity.User">
        insert into `user`(`name`,`pwd`) values (#{name},#{pwd})
    </insert>

    <update id="updateUser" parameterType="com.base.entity.User" >
        update user set `name` = #{name},`pwd` = #{pwd} where id = #{id};
    </update>

    <delete id="deleteById" parameterType="int" >
        delete from `user` where id = #{id}
    </delete>
</mapper>

测试类

public class UserMapperTest {

    @Test
    public void test01() {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> users = mapper.selectAll();

        for (User user : users) {
            System.out.println(user);
        }

        sqlSession.close();
    }

    @Test
    public void test02() {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = mapper.selectById(1);

        System.out.println(user);

        sqlSession.close();
    }

    @Test
    public void test03() {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        int demo02 = mapper.insertUser(new User(4, "demo02", "123456"));

        sqlSession.commit();
        sqlSession.close();

        test01();
    }

    @Test
    public void test04() {
        SqlSession sqlSession = MybatisUtils.getSqlSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        int newDemo01 = mapper.updateUser(new User(6, "newDemo01", "123456"));

        sqlSession.commit();
        sqlSession.close();

        test01();
    }

    @Test
    public void test05() {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        int i = mapper.deleteById(8);

        sqlSession.commit();
        sqlSession.close();
        test01();
    }
}