MyBatis框架的使用及源码分析(一) 配置与使用

我们先来看一个例子，简单的了解一下mybatis的mapper接口方式的使用。

 package org.mybatis.spring.sample;

 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 org.junit.Test;

 import org.mybatis.spring.sample.bean.User;

 import org.mybatis.spring.sample.mapper.UserMapper;

 import java.io.IOException;

 public class MybatisTest {

     /**

      * 读取mybatis的配置文件，生成SqlSessionFactory

      *

      * @return

      */

     private static SqlSessionFactory getSessionFactory() {

         SqlSessionFactory sessionFactory = null;

         String resource = "mybatisConfig.xml";

         try {

             sessionFactory = new SqlSessionFactoryBuilder().build(Resources

                     .getResourceAsReader(resource));

         } catch (IOException e) {

             e.printStackTrace();

         }

         return sessionFactory;

     }

     @Test

     public void findUserById() {

         SqlSessionFactory sqlSessionFactory = getSessionFactory();

         SqlSession sqlSession = sqlSessionFactory.openSession();

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

         User user = userMapper.selectByPrimaryKey(1l);

         System.out.println(user.getId() + " /  " + user.getName());

     }

 }

输出结果

1 /  赵大

数据库表 user

User.java

 /*

  * User.java

  * Copyright(C) 2015-2017 Jstudio.org

  * All rights reserved.

  * --------------------------------------

  * 2017-09-17 Created.

  */

 package org.mybatis.spring.sample.bean;

 import java.io.Serializable;

 /**

  *

  * This class was generated by MyBatis Generator.

  * This class corresponds to the database table user

  *

  * @mbg.generated do_not_delete_during_merge 2017-09-17

  */

 public class User implements Serializable {

     /**

      * 主键

      */

     private Long id;

     /**

      * 用户名

      */

     private String name;

     /**

      * 密码

      */

     private String password;

     /**

      * 电子邮件

      */

     private String email;

     /**

      * 年龄

      */

     private Integer age;

     private static final long serialVersionUID = 1L;

     /**

      * 获取主键

      *

      * @return id - 主键

      */

     public Long getId() {

         return id;

     }

     /**

      * 设置主键

      *

      * @param id 主键

      */

     public void setId(Long id) {

         this.id = id;

     }

     /**

      * 获取用户名

      *

      * @return name - 用户名

      */

     public String getName() {

         return name;

     }

     /**

      * 设置用户名

      *

      * @param name 用户名

      */

     public void setName(String name) {

         this.name = name == null ? null : name.trim();

     }

     /**

      * 获取密码

      *

      * @return password - 密码

      */

     public String getPassword() {

         return password;

     }

     /**

      * 设置密码

      *

      * @param password 密码

      */

     public void setPassword(String password) {

         this.password = password == null ? null : password.trim();

     }

     /**

      * 获取电子邮件

      *

      * @return email - 电子邮件

      */

     public String getEmail() {

         return email;

     }

     /**

      * 设置电子邮件

      *

      * @param email 电子邮件

      */

     public void setEmail(String email) {

         this.email = email == null ? null : email.trim();

     }

     /**

      * 获取年龄

      *

      * @return age - 年龄

      */

     public Integer getAge() {

         return age;

     }

     /**

      * 设置年龄

      *

      * @param age 年龄

      */

     public void setAge(Integer age) {

         this.age = age;

     }

 }

UserMapper.java

 /*

  * UserMapper.java

  * Copyright(C) 2015-2017 Jstudio.org

  * All rights reserved.

  * --------------------------------------

  * 2017-09-17 Created.

  */

 package org.mybatis.spring.sample.mapper;

 import org.mybatis.spring.sample.bean.User;

 import java.util.List;

 public interface UserMapper {

     int insert(User entity);

     int insertSelective(User entity);

     int deleteByPrimaryKey(Long id);

     int updateByPrimaryKeySelective(User entity);

     int updateByPrimaryKey(User entity);

     User selectByPrimaryKey(Long id);

 }

UserMapper.xml

 <?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="org.mybatis.spring.sample.mapper.UserMapper">

   <!--  This is automatically generated by MyBatis Generator on 2017-09-17. -->

   <resultMap id="BaseResultMap" type="org.mybatis.spring.sample.bean.User">

     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->

     <id column="id" jdbcType="BIGINT" property="id" />

     <result column="name" jdbcType="VARCHAR" property="name" />

     <result column="password" jdbcType="VARCHAR" property="password" />

     <result column="email" jdbcType="VARCHAR" property="email" />

     <result column="age" jdbcType="INTEGER" property="age" />

   </resultMap>

   <sql id="Base_Column_List">

     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->

     id, name, password, email, age

   </sql>

   <select id="selectByPrimaryKey" parameterType="java.lang.Long" resultMap="BaseResultMap">

     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->

     select

     <include refid="Base_Column_List" />

     from user

     where id = #{id,jdbcType=BIGINT}

   </select>

   <delete id="deleteByPrimaryKey" parameterType="java.lang.Long">

     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->

     delete from user

     where id = #{id,jdbcType=BIGINT}

   </delete>

   <insert id="insert" parameterType="org.mybatis.spring.sample.bean.User">

     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->

     <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Long">

       SELECT LAST_INSERT_ID()

     </selectKey>

     insert into user (name, password, email,

       age)

     values (#{name,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR}, #{email,jdbcType=VARCHAR},

       #{age,jdbcType=INTEGER})

   </insert>

   <insert id="insertSelective" parameterType="org.mybatis.spring.sample.bean.User">

     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->

     <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Long">

       SELECT LAST_INSERT_ID()

     </selectKey>

     insert into user

     <trim prefix="(" suffix=")" suffixOverrides=",">

       <if test="name != null">

         name,

       </if>

       <if test="password != null">

         password,

       </if>

       <if test="email != null">

         email,

       </if>

       <if test="age != null">

         age,

       </if>

     </trim>

     <trim prefix="values (" suffix=")" suffixOverrides=",">

       <if test="name != null">

         #{name,jdbcType=VARCHAR},

       </if>

       <if test="password != null">

         #{password,jdbcType=VARCHAR},

       </if>

       <if test="email != null">

         #{email,jdbcType=VARCHAR},

       </if>

       <if test="age != null">

         #{age,jdbcType=INTEGER},

       </if>

     </trim>

   </insert>

   <update id="updateByPrimaryKeySelective" parameterType="org.mybatis.spring.sample.bean.User">

     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->

     update user

     <set>

       <if test="name != null">

         name = #{name,jdbcType=VARCHAR},

       </if>

       <if test="password != null">

         password = #{password,jdbcType=VARCHAR},

       </if>

       <if test="email != null">

         email = #{email,jdbcType=VARCHAR},

       </if>

       <if test="age != null">

         age = #{age,jdbcType=INTEGER},

       </if>

     </set>

     where id = #{id,jdbcType=BIGINT}

   </update>

   <update id="updateByPrimaryKey" parameterType="org.mybatis.spring.sample.bean.User">

     <!--  WARNING - This element is automatically generated by MyBatis Generator, modify carefully. -->

     update user

     set name = #{name,jdbcType=VARCHAR},

       password = #{password,jdbcType=VARCHAR},

       email = #{email,jdbcType=VARCHAR},

       age = #{age,jdbcType=INTEGER}

     where id = #{id,jdbcType=BIGINT}

   </update>

  </mapper>

mybatisConfig.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>

    <environments default="development">

        <environment id="development">

            <transactionManager type="JDBC"/>

            <dataSource type="POOLED">

                <property name="driver" value="com.mysql.jdbc.Driver"/>

                <property name="url" value="jdbc:mysql://127.0.0.1:3306/test"/>

                <property name="username" value="root"/>

                <property name="password" value="123456"/>

            </dataSource>

        </environment>

    </environments>

    <mappers>

        <mapper resource="sqlmapping/UserMapper.xml"/>

    </mappers>

</configuration>

后继我们将继续讲解Mybatis如何加载配置，解析Mappper的xml,创建和使用Mapper。

巴特西

MyBatis框架的使用及源码分析(一) 配置与使用

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