Mybatis屬於半自動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，由於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

1、在G盤新建一個文件夾，命名：generator（或者其他盤其他名字也可以，之所以用這個，是為了copy下面代碼後，不用再做修改路徑）

2、準備需要的jar包：mybatis-generator-core-1.3.2.jar、MySQL-connector-Java-5.1.34.jar（忽略版本號，這只是我用的jar 版本）

3、新建一個文件，命名：generatorConfig.xml

以下是相關文件截圖:

和Hibernate逆向生成一樣，這裏也需要一個配置文件：

generatorConfig.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
  PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
  "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
    <!--數據庫驅動-->
    <classPathEntry    location="mysql-connector-java-5.0.4-bin.jar"/>
    <context id="DB2Tables"    targetRuntime="MyBatis3">
        <commentGenerator>
            <property name="suppressDate" value="true"/>
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>
        <!--數據庫鏈接地址賬號密碼-->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://localhost/test" userId="root" password="123456">
        </jdbcConnection>
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!--生成Model類存放位置-->
        <javaModelGenerator targetPackage="model" targetProject="test">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>
        <!--生成映射文件存放位置-->
        <sqlMapGenerator targetPackage="mapping" targetProject="test">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>
        <!--生成Dao類存放位置-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="dao" targetProject="test">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>
        <!--生成對應表及類名-->
        <table tableName="user" domainObjectName="User" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>
    </context>
</generatorConfiguration>

需要修改文件配置的地方我都已經把註釋標註出來了，這裏的相關路徑（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：

User.java

package model;

public class User {
    private Integer uid;

    private String username;

    private String password;

    private String name;

    private String email;

    private String phone;

    private String addr;

    private Integer state;

    private String code;

    public Integer getUid() {
        return uid;
    }

    public void setUid(Integer uid) {
        this.uid = uid;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username == null ? null : username.trim();
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password == null ? null : password.trim();
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name == null ? null : name.trim();
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email == null ? null : email.trim();
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone == null ? null : phone.trim();
    }

    public String getAddr() {
        return addr;
    }

    public void setAddr(String addr) {
        this.addr = addr == null ? null : addr.trim();
    }

    public Integer getState() {
        return state;
    }

    public void setState(Integer state) {
        this.state = state;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code == null ? null : code.trim();
    }
}

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="dao.UserMapper" >
  <resultMap id="BaseResultMap" type="model.User" >
    <id column="uid" property="uid" jdbcType="INTEGER" />
    <result column="username" property="username" jdbcType="VARCHAR" />
    <result column="password" property="password" jdbcType="VARCHAR" />
    <result column="name" property="name" jdbcType="VARCHAR" />
    <result column="email" property="email" jdbcType="VARCHAR" />
    <result column="phone" property="phone" jdbcType="VARCHAR" />
    <result column="addr" property="addr" jdbcType="VARCHAR" />
    <result column="state" property="state" jdbcType="INTEGER" />
    <result column="code" property="code" jdbcType="VARCHAR" />
  </resultMap>
  <sql id="Base_Column_List" >
    uid, username, password, name, email, phone, addr, state, code
  </sql>
  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select 
    <include refid="Base_Column_List" />
    from user
    where uid = #{uid,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    delete from user
    where uid = #{uid,jdbcType=INTEGER}
  </delete>
  <insert id="insert" parameterType="model.User" >
    insert into user (uid, username, password, 
      name, email, phone, 
      addr, state, code)
    values (#{uid,jdbcType=INTEGER}, #{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR}, 
      #{name,jdbcType=VARCHAR}, #{email,jdbcType=VARCHAR}, #{phone,jdbcType=VARCHAR}, 
      #{addr,jdbcType=VARCHAR}, #{state,jdbcType=INTEGER}, #{code,jdbcType=VARCHAR})
  </insert>
  <insert id="insertSelective" parameterType="model.User" >
    insert into user
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="uid != null" >
        uid,
      </if>
      <if test="username != null" >
        username,
      </if>
      <if test="password != null" >
        password,
      </if>
      <if test="name != null" >
        name,
      </if>
      <if test="email != null" >
        email,
      </if>
      <if test="phone != null" >
        phone,
      </if>
      <if test="addr != null" >
        addr,
      </if>
      <if test="state != null" >
        state,
      </if>
      <if test="code != null" >
        code,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="uid != null" >
        #{uid,jdbcType=INTEGER},
      </if>
      <if test="username != null" >
        #{username,jdbcType=VARCHAR},
      </if>
      <if test="password != null" >
        #{password,jdbcType=VARCHAR},
      </if>
      <if test="name != null" >
        #{name,jdbcType=VARCHAR},
      </if>
      <if test="email != null" >
        #{email,jdbcType=VARCHAR},
      </if>
      <if test="phone != null" >
        #{phone,jdbcType=VARCHAR},
      </if>
      <if test="addr != null" >
        #{addr,jdbcType=VARCHAR},
      </if>
      <if test="state != null" >
        #{state,jdbcType=INTEGER},
      </if>
      <if test="code != null" >
        #{code,jdbcType=VARCHAR},
      </if>
    </trim>
  </insert>
  <update id="updateByPrimaryKeySelective" parameterType="model.User" >
    update user
    <set >
      <if test="username != null" >
        username = #{username,jdbcType=VARCHAR},
      </if>
      <if test="password != null" >
        password = #{password,jdbcType=VARCHAR},
      </if>
      <if test="name != null" >
        name = #{name,jdbcType=VARCHAR},
      </if>
      <if test="email != null" >
        email = #{email,jdbcType=VARCHAR},
      </if>
      <if test="phone != null" >
        phone = #{phone,jdbcType=VARCHAR},
      </if>
      <if test="addr != null" >
        addr = #{addr,jdbcType=VARCHAR},
      </if>
      <if test="state != null" >
        state = #{state,jdbcType=INTEGER},
      </if>
      <if test="code != null" >
        code = #{code,jdbcType=VARCHAR},
      </if>
    </set>
    where uid = #{uid,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="model.User" >
    update user
    set username = #{username,jdbcType=VARCHAR},
      password = #{password,jdbcType=VARCHAR},
      name = #{name,jdbcType=VARCHAR},
      email = #{email,jdbcType=VARCHAR},
      phone = #{phone,jdbcType=VARCHAR},
      addr = #{addr,jdbcType=VARCHAR},
      state = #{state,jdbcType=INTEGER},
      code = #{code,jdbcType=VARCHAR}
    where uid = #{uid,jdbcType=INTEGER}
  </update>
</mapper>

UserMapper.java

package dao;

import model.User;

public interface UserMapper {
    int deleteByPrimaryKey(Integer uid);

    int insert(User record);

    int insertSelective(User record);

    User selectByPrimaryKey(Integer uid);

    int updateByPrimaryKeySelective(User record);

    int updateByPrimaryKey(User record);
}

使用Mybatis-Generator自動生成Dao、Model、Mapping相關文件