Mybatis+MySQL增删改查

一、创建数据库

在库中创建一个表格t_user:

 

 

二、创建实体类

创建实体类User.java，类中的一些属性对应表中的字段。

User.java:

public class User {

    private Integer id;
    private String username;
    private String password;
    private Integer age;
    private String sex;
    private String email;

    public User() {
    }

    public User(Integer id, String username, String password, Integer age, String sex, String email) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.age = age;
        this.sex = sex;
        this.email = email;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", age=" + age +
                ", sex='" + sex + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}

 

三、编写映射文件

UserMapper.xml:

    <!--添加用户-->
    <insert id="insertUser">
        insert into t_user (username, password, sex, age, email)
        values (#{username}, #{password}, #{sex}, #{age}, #{email})
    </insert>
    <!--查询用户-->
    <select id="findUserById" parameterType="int" resultType="com.ang.demo1.User">
        select *
        from t_user
        where id = #{id}
    </select>
    <!--修改用户-->
    <update id="updateUser" parameterType="com.ang.demo1.User">
        update t_user
        set username = #{username},
            password = #{password},
            sex = #{sex},
            age = #{age},
            email = #{email} where id = #{id}
    </update>
    <!--删除用户-->
    <delete id="deleteUserById" parameterType="int">
        delete from t_user where id = #{id}
    </delete>

 

四、编写测试方法

public class TestMybatis {
    private SqlSessionFactory sqlSessionFactory;
    private SqlSession sqlSession;
    private int result;

    @Before
    public void init() {
        //加载核心配置文件
        try (InputStream is = Resources.getResourceAsStream("mybatis-config.xml")) {
            //获取SqlSessionFactoryBuilder
            SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
            //获取SqlSessionFactory
            sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
            //获取SqlSession
            sqlSession = sqlSessionFactory.openSession();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Test
    public void testUser() {
        //添加
        User user1 = new User();
        user1.setAge(18);
        user1.setEmail("123@qq.com");
        user1.setSex("男");
        user1.setPassword("123456");
        user1.setUsername("admin");
        result = sqlSession.insert("insertUser",user1);
        if(result > 0) {
            System.out.println("添加成功");
        }
        //查找
        User user2 = sqlSession.selectOne("findUserById",3);
        System.out.println(user2.toString());
        //修改
        User user3 = sqlSession.selectOne("findUser",2);
        user3.setUsername("admin1");
        result = sqlSession.update("updateUser",user3);
        if(result > 0) {
            System.out.println("更新成功");
        }
        //删除
        result = sqlSession.delete("deleteUserById",5);
        if(result > 0) {
            System.out.println("成功删除了"+result+"条记录");
        }
    }

    @After
    public void destroy() {
        //提交事务
        sqlSession.commit();
        //关闭sqlSession
        sqlSession.close();
    }
}