Mybatis屬于半自動ORM，在使用這個框架中，工作量最大的就是書寫Mapping的映射文件，由于手動書寫很容易出錯，我們可以利用Mybatis-Generator來幫我們自動生成文件。

1、相關文件

關于Mybatis-Generator的下載可以到這個地址：https://github.com/mybatis/generator/releases

由于我使用的是MySQL數據庫，這里需要再準備一個連接mysql數據庫的驅動jar包

以下是相關文件截圖:

和Hibernate逆向生成一樣，這里也需要一個配置文件：

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     <!--數據庫驅動--> 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         <!--數據庫鏈接地址賬號密碼-->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類存放位置-->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類存放位置-->29         <javaClientGenerator type="XMLMAPPER" targetPackage="lcw.dao" targetProject="src">30             <property name="enableSubPackages" value="true"/>31         </javaClientGenerator>32         <!--生成對應表及類名-->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經把注釋標注出來了，這里的相關路徑（如數據庫驅動包，生成對應的相關文件位置可以自定義）不能帶有中文。

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為必選項，分別代表數據庫表名和生成的實體類名，其余的可以自定義去選擇（一般情況下均為false）。

生成語句文件：

java -jar mybatis-generator-core-1.3.2.jar -configfile generatorConfig.xml -overwrite

2、使用方法

在該目錄按住Shift鍵，右鍵鼠標選擇"在此處打開命令窗口"，復制粘貼生成語句的文件代碼即可。

看下效果圖：

首先這個是我的數據庫表

生成相關代碼：

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 }