Mybatis

1. mybatis-config.xml

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

    <!--导入属性配置-->
    <properties resource="datasource.properties"></properties>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${db.driverClassName}"/>
                <property name="url" value="${db.url}"/>
                <property name="username" value="${db.username}"/>
                <property name="password" value="${db.password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mappers/UserMapper.xml"/>
    </mappers>
</configuration>

2.pojo

<?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" >
<mapper namespace="com.love.lee.dao.UserMapper" >
  <resultMap id="BaseResultMap" type="com.love.lee.pojo.User" >
    <constructor >
      <idArg column="id" jdbcType="INTEGER" javaType="java.lang.Integer" />
      <arg column="username" jdbcType="VARCHAR" javaType="java.lang.String" />
      <arg column="password" jdbcType="VARCHAR" javaType="java.lang.String" />
      <arg column="email" jdbcType="VARCHAR" javaType="java.lang.String" />
      <arg column="phone" jdbcType="VARCHAR" javaType="java.lang.String" />
      <arg column="question" jdbcType="VARCHAR" javaType="java.lang.String" />
      <arg column="answer" jdbcType="VARCHAR" javaType="java.lang.String" />
      <arg column="role" jdbcType="INTEGER" javaType="java.lang.Integer" />
      <arg column="create_time" jdbcType="TIMESTAMP" javaType="java.util.Date" />
      <arg column="update_time" jdbcType="TIMESTAMP" javaType="java.util.Date" />
    </constructor>
  </resultMap>
  <sql id="Base_Column_List" >
    id, username, password, email, phone, question, answer, role, create_time, update_time
  </sql>
  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select 
    <include refid="Base_Column_List" />
    from mmall_user
    where id = #{id,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    delete from mmall_user
    where id = #{id,jdbcType=INTEGER}
  </delete>
  <insert id="insert" parameterType="com.love.lee.pojo.User" >
    insert into mmall_user (id, username, password, 
      email, phone, question, 
      answer, role, create_time, 
      update_time)
    values (#{id,jdbcType=INTEGER}, #{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR}, 
      #{email,jdbcType=VARCHAR}, #{phone,jdbcType=VARCHAR}, #{question,jdbcType=VARCHAR}, 
      #{answer,jdbcType=VARCHAR}, #{role,jdbcType=INTEGER}, now(),
      now())
  </insert>
  <insert id="insertSelective" parameterType="com.love.lee.pojo.User" >
    insert into mmall_user
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        id,
      </if>
      <if test="username != null" >
        username,
      </if>
      <if test="password != null" >
        password,
      </if>
      <if test="email != null" >
        email,
      </if>
      <if test="phone != null" >
        phone,
      </if>
      <if test="question != null" >
        question,
      </if>
      <if test="answer != null" >
        answer,
      </if>
      <if test="role != null" >
        role,
      </if>
      <if test="createTime != null" >
        create_time,
      </if>
      <if test="updateTime != null" >
        update_time,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        #{id,jdbcType=INTEGER},
      </if>
      <if test="username != null" >
        #{username,jdbcType=VARCHAR},
      </if>
      <if test="password != null" >
        #{password,jdbcType=VARCHAR},
      </if>
      <if test="email != null" >
        #{email,jdbcType=VARCHAR},
      </if>
      <if test="phone != null" >
        #{phone,jdbcType=VARCHAR},
      </if>
      <if test="question != null" >
        #{question,jdbcType=VARCHAR},
      </if>
      <if test="answer != null" >
        #{answer,jdbcType=VARCHAR},
      </if>
      <if test="role != null" >
        #{role,jdbcType=INTEGER},
      </if>
      <if test="createTime != null" >
        now(),
      </if>
      <if test="updateTime != null" >
        now(),
      </if>
    </trim>
  </insert>
  <update id="updateByPrimaryKeySelective" parameterType="com.love.lee.pojo.User" >
    update mmall_user
    <set >
      <if test="username != null" >
        username = #{username,jdbcType=VARCHAR},
      </if>
      <if test="password != null" >
        password = #{password,jdbcType=VARCHAR},
      </if>
      <if test="email != null" >
        email = #{email,jdbcType=VARCHAR},
      </if>
      <if test="phone != null" >
        phone = #{phone,jdbcType=VARCHAR},
      </if>
      <if test="question != null" >
        question = #{question,jdbcType=VARCHAR},
      </if>
      <if test="answer != null" >
        answer = #{answer,jdbcType=VARCHAR},
      </if>
      <if test="role != null" >
        role = #{role,jdbcType=INTEGER},
      </if>
      <if test="createTime != null" >
        create_time = #{createTime,jdbcType=TIMESTAMP},
      </if>
      <if test="updateTime != null" >
        update_time = now(),
      </if>
    </set>
    where id = #{id,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.love.lee.pojo.User" >
    update mmall_user
    set username = #{username,jdbcType=VARCHAR},
      password = #{password,jdbcType=VARCHAR},
      email = #{email,jdbcType=VARCHAR},
      phone = #{phone,jdbcType=VARCHAR},
      question = #{question,jdbcType=VARCHAR},
      answer = #{answer,jdbcType=VARCHAR},
      role = #{role,jdbcType=INTEGER},
      create_time = #{createTime,jdbcType=TIMESTAMP},
      update_time = now()
    where id = #{id,jdbcType=INTEGER}
  </update>
  
  
  <select id="checkUsername" resultType="int" parameterType="string" >
    select count(1) from mmall_user
    where username = #{username}
  </select>

  <select id="checkEmail" resultType="int" parameterType="string" >
    select count(1) from mmall_user
    where email = #{email}
  </select>


  <select id="selectLogin" resultMap="BaseResultMap" parameterType="map">
    SELECT
--     *???//这样真的好么?答案就是,这样不好.
    <include refid="Base_Column_List" />
    from mmall_user
    where username = #{username}
    and password = #{password}
  </select>


  <select id="selectQuestionByUsername" resultType="string" parameterType="string">
    select
    question
    from mmall_user
    where username = #{username}
  </select>

  <select id="checkAnswer" resultType="int" parameterType="map">
    SELECT
    count(1)
    from mmall_user
    where username=#{username}
    and question = #{question}
    and answer = #{answer}
  </select>

  <update id="updatePasswordByUsername" parameterType="map">
    update mmall_user
    SET password = #{passwordNew},update_time = now()
    where username = #{username}
  </update>

  <select id="checkPassword" resultType="int" parameterType="map">
    SELECT
    count(1)
    from mmall_user
    where password = #{password}
    and id = #{userId}
  </select>


  <select id="checkEmailByUserId" resultType="int" parameterType="map">
    select count(1) from mmall_user
    where email = #{email}
    and id != #{userId}
  </select>


</mapper>

3. 接口

package com.love.lee.dao;


import com.love.lee.pojo.User;
import org.apache.ibatis.annotations.Param;

public interface UserMapper {
    int deleteByPrimaryKey(Integer id);

    int insert(User record);

    int insertSelective(User record);

    User selectByPrimaryKey(Integer id);

    int updateByPrimaryKeySelective(User record);

    int updateByPrimaryKey(User record);

    int checkUsername(String username);

    int checkEmail(String email);

    User selectLogin(@Param("username") String username, @Param("password") String password);

    String selectQuestionByUsername(String username);

    int checkAnswer(@Param("username") String username, @Param("question") String question, @Param("answer") String answer);

    int updatePasswordByUsername(@Param("username") String username, @Param("passwordNew") String passwordNew);

    int checkPassword(@Param(value = "password") String password, @Param("userId") Integer userId);

    int checkEmailByUserId(@Param(value = "email") String email, @Param(value = "userId") Integer userId);
}

4.调用

Reader reader = Resources.getResourceAsReader("mybatis-config.xml");

        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);

        SqlSession sqlSession = sqlSessionFactory.openSession();


 try {
            sqlSession = dao.getSqlSession();
            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
            User user = userMapper.selectByPrimaryKey(1);
            System.out.println(user.toString());

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (sqlSession != null) {
                sqlSession.close();
            }
        }