Mybatis属于半自动ORM，在使用这个框架中，工作量最大的就是书写Mapping的映射文件，由于手动书写很容易出错，我们可以利用Mybatis-Generator来帮我们自动生成文件。
1、相关文件
关于Mybatis-Generator的下载可以到这个地址：https://github.com/mybatis/generator/releases
由于我使用的是Mysql数据库，这里需要在准备一个连接mysql数据库的驱动jar包
以下是相关文件截图:
和Hibernate逆向生成一样，这里也需要一个配置文件：
generatorConfig.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE generatorConfiguration 3 PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN" 4 "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd"> 5 <generatorConfiguration> 6 <!--数据库驱动--> 7 <classPathEntry location="mysql-connector-java-5.0.8-bin.jar"/> 8 <context id="DB2Tables" targetRuntime="MyBatis3"> 9 <commentGenerator>10 <property name="suppressDate" value="true"/>11 <property name="suppressAllComments" value="true"/>12 </commentGenerator>13 <!--数据库链接地址账号密码-->14 <jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://localhost/mymessages" userId="root" password="root">15 </jdbcConnection>16 <javaTypeResolver>17 <property name="forceBigDecimals" value="false"/>18 </javaTypeResolver>19 <!--生成Model类存放位置-->20 <javaModelGenerator targetPackage="lcw.model" targetProject="src">21 <property name="enableSubPackages" value="true"/>22 <property name="trimStrings" value="true"/>23 </javaModelGenerator>24 <!--生成映射文件存放位置-->25 <sqlMapGenerator targetPackage="lcw.mapping" targetProject="src">26 <property name="enableSubPackages" value="true"/>27 </sqlMapGenerator>28 <!--生成Dao类存放位置-->29 <javaClientGenerator type="XMLMAPPER" targetPackage="lcw.dao" targetProject="src">30 <property name="enableSubPackages" value="true"/>31 </javaClientGenerator>32 <!--生成对应表及类名-->33 <table tableName="message" domainObjectName="Messgae" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>34 </context>35 </generatorConfiguration>
需要修改文件配置的地方我都已经把注释标注出来了，这里的相关路径（如数据库驱动包，生成对应的相关文件位置可以自定义）不能带有中文。
上面配置文件中的：
<table tableName="message" domainObjectName="Messgae" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>
tableName和domainObjectName为必选项，分别代表数据库表名和生成的实力类名，其余的可以自定义去选择（一般情况下均为false）。
生成语句文件：
java -jar mybatis-generator-core-1.3.2.jar -configfile generatorConfig.xml -overwrite
2、使用方法
在该目录按住Shift键，右键鼠标选择"在此处打开命令窗口"，复制粘贴生成语句的文件代码即可。
看下效果图：
生成相关代码：
Message.java
1 package lcw.model; 2 3 public class Messgae { 4 private Integer id; 5 6 private String title; 7 8 private String describe; 9 10 private String content;11 12 public Integer getId() {13 return id;14 }15 16 public void setId(Integer id) {17 this.id = id;18 }19 20 public String getTitle() {21 return title;22 }23 24 public void setTitle(String title) {25 this.title = title == null ? null : title.trim();26 }27 28 public String getDescribe() {29 return describe;30 }31 32 public void setDescribe(String describe) {33 this.describe = describe == null ? null : describe.trim();34 }35 36 public String getContent() {37 return content;38 }39 40 public void setContent(String content) {41 this.content = content == null ? null : content.trim();42 }43 }
MessgaeMapper.xml
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > 3 <mapper namespace="lcw.dao.MessgaeMapper" > 4 <resultMap id="BaseResultMap" type="lcw.model.Messgae" > 5 <id column="id" property="id" jdbcType="INTEGER" /> 6 <result column="title" property="title" jdbcType="VARCHAR" /> 7 <result column="describe" property="describe" jdbcType="VARCHAR" /> 8 <result column="content" property="content" jdbcType="VARCHAR" /> 9 </resultMap>10 <sql id="Base_Column_List" >11 id, title, describe, content12 </sql>13 <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >14 select 15 <include refid="Base_Column_List" />16 from message17 where id = #{id,jdbcType=INTEGER}18 </select>19 <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >20 delete from message21 where id = #{id,jdbcType=INTEGER}22 </delete>23 <insert id="insert" parameterType="lcw.model.Messgae" >24 insert into message (id, title, describe, 25 content)26 values (#{id,jdbcType=INTEGER}, #{title,jdbcType=VARCHAR}, #{describe,jdbcType=VARCHAR}, 27 #{content,jdbcType=VARCHAR})28 </insert>29 <insert id="insertSelective" parameterType="lcw.model.Messgae" >30 insert into message31 <trim prefix="(" suffix=")" suffixOverrides="," >32 <if test="id != null" >33 id,34 </if>35 <if test="title != null" >36 title,37 </if>38 <if test="describe != null" >39 describe,40 </if>41 <if test="content != null" >42 content,43 </if>44 </trim>45 <trim prefix="values (" suffix=")" suffixOverrides="," >46 <if test="id != null" >47 #{id,jdbcType=INTEGER},48 </if>49 <if test="title != null" >50 #{title,jdbcType=VARCHAR},51 </if>52 <if test="describe != null" >53 #{describe,jdbcType=VARCHAR},54 </if>55 <if test="content != null" >56 #{content,jdbcType=VARCHAR},57 </if>58 </trim>59 </insert>60 <update id="updateByPrimaryKeySelective" parameterType="lcw.model.Messgae" >61 update message62 <set >63 <if test="title != null" >64 title = #{title,jdbcType=VARCHAR},65 </if>66 <if test="describe != null" >67 describe = #{describe,jdbcType=VARCHAR},68 </if>69 <if test="content != null" >70 content = #{content,jdbcType=VARCHAR},71 </if>72 </set>73 where id = #{id,jdbcType=INTEGER}74 </update>75 <update id="updateByPrimaryKey" parameterType="lcw.model.Messgae" >76 update message77 set title = #{title,jdbcType=VARCHAR},78 describe = #{describe,jdbcType=VARCHAR},79 content = #{content,jdbcType=VARCHAR}80 where id = #{id,jdbcType=INTEGER}81 </update>82 </mapper>
MessgaeMapper.java
1 package lcw.dao; 2 3 import lcw.model.Messgae; 4 5 public interface MessgaeMapper { 6 int deleteByPrimaryKey(Integer id); 7 8 int insert(Messgae record); 9 10 int insertSelective(Messgae record);11 12 Messgae selectByPrimaryKey(Integer id);13 14 int updateByPrimaryKeySelective(Messgae record);15 16 int updateByPrimaryKey(Messgae record);17 }