MyBatis学习总结（9）——使用MyBatis Generator自动创建代码

一、构建一个环境

1. 首先创建一个表：

 CREATE TABLE
     t_user
     (
         USER_ID INT NOT NULL AUTO_INCREMENT,
         USER_NAME CHAR(30) NOT NULL,
         USER_PASSWORD CHAR(10) NOT NULL,
         USER_EMAIL CHAR(30) NOT NULL,
         PRIMARY KEY (USER_ID)
     )
     ENGINE=InnoDB DEFAULT CHARSET=utf8;

2. 在 Mybatis 主页 http://code.google.com/p/mybatis/ 上下载 Mybatis mybatis-generator-core 或者在这里下载：http://download.csdn.net/detail/evankaka/8926999

二、xml文件编写

1、新建一个工程。然后新建如下包，都是空的

2、然后新建generator.xmll文件

内容如下：

 <?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>
     <!-- classPathEntry:数据库的JDBC驱动的jar包地址 -->
     <classPathEntry location="D:\Java\Jar\mysql-connector-java-5.1.22\mysql-connector-java-5.1.22-bin.jar" />
     <context id="DB2Tables" targetRuntime="MyBatis3">
         <commentGenerator>
         <!-- 抑制警告 -->
         <property name="suppressTypeWarnings" value="true" />
         <!-- 是否去除自动生成的注释 true：是 ： false:否 -->
         <property name="suppressAllComments" value="false" />
         <!-- 是否生成注释代时间戳-->
         <property name="suppressDate" value="true" />
         </commentGenerator>

         <!--数据库连接的信息：驱动类、连接地址、用户名、密码 -->
         <jdbcConnection driverClass="com.mysql.jdbc.Driver"
             connectionURL="jdbc:mysql://localhost/learning" userId="root"
             password="christmas258@">
         </jdbcConnection>
         <!-- 默认false，把JDBC DECIMAL 和 NUMERIC 类型解析为 Integer true，把JDBC DECIMAL 和
             NUMERIC 类型解析为java.math.BigDecimal -->
     <!--     <javaTypeResolver>
             <property name="forceBigDecimals" value="false" />
         </javaTypeResolver> -->
         <!--生成Model类存放位置 -->
         <javaModelGenerator targetPackage="com.lin.domain"
             targetProject="D:\lunaJee-workspace\MyBatisLearningChapter7\src">
              <!-- 是否在当前路径下新加一层schema,eg：fase路径com.oop.eksp.user.model， true:com.oop.eksp.user.model.[schemaName] -->
             <property name="enableSubPackages" value="false" />
              <!-- 是否针对string类型的字段在set的时候进行trim调用 -->
             <property name="trimStrings" value="true" />
         </javaModelGenerator>
         <!--生成映射文件存放位置 -->
         <sqlMapGenerator targetPackage="com.lin.mapper"
             targetProject="D:\lunaJee-workspace\MyBatisLearningChapter7\src">
             <property name="enableSubPackages" value="true" />
         </sqlMapGenerator>
         <!--生成Dao类存放位置 -->
         <javaClientGenerator type="XMLMAPPER"
             targetPackage="com.lin.dao" targetProject="D:\lunaJee-workspace\MyBatisLearningChapter7\src">
             <property name="enableSubPackages" value="true" />
         </javaClientGenerator>


         <!-- tableName:用于自动生成代码的数据库表；domainObjectName:对应于数据库表的javaBean类名 -->
         <table schema="general" tableName="T_USER" domainObjectName="User">
          <!--domain字段的命名规则，false:默认为驼峰命名 true:按数据库真实命名  -->
         <property name="useActualColumnNames" value="false"/>
         <!-- 忽略列，不生成bean 字段 -->
         <!--     <ignoreColumn column="FRED" />   -->
         <!-- 指定列的java数据类型 -->
         <!--     <columnOverride column="LONG_VARCHAR_FIELD" jdbcType="VARCHAR" />   -->
         </table>
     </context>
 </generatorConfiguration>

三、自动代码生成

自动代码生成有4种方法

1、直接cmd下命令行生成

命令如下：java -jar 电脑上mybatis-generator-core-1.3.0.jar的绝对路径  -configfile 电脑上generator.xml的绝对路径，这里的generator.xml不一定要放在工程的src文件中。

如我的这个项目就是：

运行的结果如下：

然后在eclipse中刷新一下：结果出来了

看看各个文件

（1）User.java

 package com.lin.domain;

 public class User {
     /**
      * This field was generated by MyBatis Generator.
      * This field corresponds to the database column t_user.USER_ID
      *
      * @mbggenerated
      */
     private Integer userId;

     /**
      * This field was generated by MyBatis Generator.
      * This field corresponds to the database column t_user.USER_NAME
      *
      * @mbggenerated
      */
     private String userName;

     /**
      * This field was generated by MyBatis Generator.
      * This field corresponds to the database column t_user.USER_PASSWORD
      *
      * @mbggenerated
      */
     private String userPassword;

     /**
      * This field was generated by MyBatis Generator.
      * This field corresponds to the database column t_user.USER_EMAIL
      *
      * @mbggenerated
      */
     private String userEmail;

     /**
      * This method was generated by MyBatis Generator.
      * This method returns the value of the database column t_user.USER_ID
      *
      * @return the value of t_user.USER_ID
      *
      * @mbggenerated
      */
     public Integer getUserId() {
         return userId;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method sets the value of the database column t_user.USER_ID
      *
      * @param userId the value for t_user.USER_ID
      *
      * @mbggenerated
      */
     public void setUserId(Integer userId) {
         this.userId = userId;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method returns the value of the database column t_user.USER_NAME
      *
      * @return the value of t_user.USER_NAME
      *
      * @mbggenerated
      */
     public String getUserName() {
         return userName;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method sets the value of the database column t_user.USER_NAME
      *
      * @param userName the value for t_user.USER_NAME
      *
      * @mbggenerated
      */
     public void setUserName(String userName) {
         this.userName = userName == null ? null : userName.trim();
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method returns the value of the database column t_user.USER_PASSWORD
      *
      * @return the value of t_user.USER_PASSWORD
      *
      * @mbggenerated
      */
     public String getUserPassword() {
         return userPassword;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method sets the value of the database column t_user.USER_PASSWORD
      *
      * @param userPassword the value for t_user.USER_PASSWORD
      *
      * @mbggenerated
      */
     public void setUserPassword(String userPassword) {
         this.userPassword = userPassword == null ? null : userPassword.trim();
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method returns the value of the database column t_user.USER_EMAIL
      *
      * @return the value of t_user.USER_EMAIL
      *
      * @mbggenerated
      */
     public String getUserEmail() {
         return userEmail;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method sets the value of the database column t_user.USER_EMAIL
      *
      * @param userEmail the value for t_user.USER_EMAIL
      *
      * @mbggenerated
      */
     public void setUserEmail(String userEmail) {
         this.userEmail = userEmail == null ? null : userEmail.trim();
     }
 }

UserExample.java这个文件可以控制是否生成

 package com.lin.domain;

 import java.util.ArrayList;
 import java.util.List;

 public class UserExample {
     /**
      * This field was generated by MyBatis Generator.
      * This field corresponds to the database table t_user
      *
      * @mbggenerated
      */
     protected String orderByClause;

     /**
      * This field was generated by MyBatis Generator.
      * This field corresponds to the database table t_user
      *
      * @mbggenerated
      */
     protected boolean distinct;

     /**
      * This field was generated by MyBatis Generator.
      * This field corresponds to the database table t_user
      *
      * @mbggenerated
      */
     protected List<Criteria> oredCriteria;

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     public UserExample() {
         oredCriteria = new ArrayList<Criteria>();
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     public void setOrderByClause(String orderByClause) {
         this.orderByClause = orderByClause;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     public String getOrderByClause() {
         return orderByClause;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     public void setDistinct(boolean distinct) {
         this.distinct = distinct;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     public boolean isDistinct() {
         return distinct;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     public List<Criteria> getOredCriteria() {
         return oredCriteria;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     public void or(Criteria criteria) {
         oredCriteria.add(criteria);
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     public Criteria or() {
         Criteria criteria = createCriteriaInternal();
         oredCriteria.add(criteria);
         return criteria;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     public Criteria createCriteria() {
         Criteria criteria = createCriteriaInternal();
         if (oredCriteria.size() == 0) {
             oredCriteria.add(criteria);
         }
         return criteria;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     protected Criteria createCriteriaInternal() {
         Criteria criteria = new Criteria();
         return criteria;
     }

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     public void clear() {
         oredCriteria.clear();
         orderByClause = null;
         distinct = false;
     }

     /**
      * This class was generated by MyBatis Generator.
      * This class corresponds to the database table t_user
      *
      * @mbggenerated
      */
     protected abstract static class GeneratedCriteria {
         protected List<Criterion> criteria;

         protected GeneratedCriteria() {
             super();
             criteria = new ArrayList<Criterion>();
         }

         public boolean isValid() {
             return criteria.size() > 0;
         }

         public List<Criterion> getCriteria() {
             return criteria;
         }

         protected void addCriterion(String condition) {
             if (condition == null) {
                 throw new RuntimeException("Value for condition cannot be null");
             }
             criteria.add(new Criterion(condition));
         }

         protected void addCriterion(String condition, Object value, String property) {
             if (value == null) {
                 throw new RuntimeException("Value for " + property + " cannot be null");
             }
             criteria.add(new Criterion(condition, value));
         }

         protected void addCriterion(String condition, Object value1, Object value2, String property) {
             if (value1 == null || value2 == null) {
                 throw new RuntimeException("Between values for " + property + " cannot be null");
             }
             criteria.add(new Criterion(condition, value1, value2));
         }

         public Criteria andUserIdIsNull() {
             addCriterion("USER_ID is null");
             return (Criteria) this;
         }

         public Criteria andUserIdIsNotNull() {
             addCriterion("USER_ID is not null");
             return (Criteria) this;
         }

         public Criteria andUserIdEqualTo(Integer value) {
             addCriterion("USER_ID =", value, "userId");
             return (Criteria) this;
         }

         public Criteria andUserIdNotEqualTo(Integer value) {
             addCriterion("USER_ID <>", value, "userId");
             return (Criteria) this;
         }

         public Criteria andUserIdGreaterThan(Integer value) {
             addCriterion("USER_ID >", value, "userId");
             return (Criteria) this;
         }

         public Criteria andUserIdGreaterThanOrEqualTo(Integer value) {
             addCriterion("USER_ID >=", value, "userId");
             return (Criteria) this;
         }

         public Criteria andUserIdLessThan(Integer value) {
             addCriterion("USER_ID <", value, "userId");
             return (Criteria) this;
         }

         public Criteria andUserIdLessThanOrEqualTo(Integer value) {
             addCriterion("USER_ID <=", value, "userId");
             return (Criteria) this;
         }

         public Criteria andUserIdIn(List<Integer> values) {
             addCriterion("USER_ID in", values, "userId");
             return (Criteria) this;
         }

         public Criteria andUserIdNotIn(List<Integer> values) {
             addCriterion("USER_ID not in", values, "userId");
             return (Criteria) this;
         }

         public Criteria andUserIdBetween(Integer value1, Integer value2) {
             addCriterion("USER_ID between", value1, value2, "userId");
             return (Criteria) this;
         }

         public Criteria andUserIdNotBetween(Integer value1, Integer value2) {
             addCriterion("USER_ID not between", value1, value2, "userId");
             return (Criteria) this;
         }

         public Criteria andUserNameIsNull() {
             addCriterion("USER_NAME is null");
             return (Criteria) this;
         }

         public Criteria andUserNameIsNotNull() {
             addCriterion("USER_NAME is not null");
             return (Criteria) this;
         }

         public Criteria andUserNameEqualTo(String value) {
             addCriterion("USER_NAME =", value, "userName");
             return (Criteria) this;
         }

         public Criteria andUserNameNotEqualTo(String value) {
             addCriterion("USER_NAME <>", value, "userName");
             return (Criteria) this;
         }

         public Criteria andUserNameGreaterThan(String value) {
             addCriterion("USER_NAME >", value, "userName");
             return (Criteria) this;
         }

         public Criteria andUserNameGreaterThanOrEqualTo(String value) {
             addCriterion("USER_NAME >=", value, "userName");
             return (Criteria) this;
         }

         public Criteria andUserNameLessThan(String value) {
             addCriterion("USER_NAME <", value, "userName");
             return (Criteria) this;
         }

         public Criteria andUserNameLessThanOrEqualTo(String value) {
             addCriterion("USER_NAME <=", value, "userName");
             return (Criteria) this;
         }

         public Criteria andUserNameLike(String value) {
             addCriterion("USER_NAME like", value, "userName");
             return (Criteria) this;
         }

         public Criteria andUserNameNotLike(String value) {
             addCriterion("USER_NAME not like", value, "userName");
             return (Criteria) this;
         }

         public Criteria andUserNameIn(List<String> values) {
             addCriterion("USER_NAME in", values, "userName");
             return (Criteria) this;
         }

         public Criteria andUserNameNotIn(List<String> values) {
             addCriterion("USER_NAME not in", values, "userName");
             return (Criteria) this;
         }

         public Criteria andUserNameBetween(String value1, String value2) {
             addCriterion("USER_NAME between", value1, value2, "userName");
             return (Criteria) this;
         }

         public Criteria andUserNameNotBetween(String value1, String value2) {
             addCriterion("USER_NAME not between", value1, value2, "userName");
             return (Criteria) this;
         }

         public Criteria andUserPasswordIsNull() {
             addCriterion("USER_PASSWORD is null");
             return (Criteria) this;
         }

         public Criteria andUserPasswordIsNotNull() {
             addCriterion("USER_PASSWORD is not null");
             return (Criteria) this;
         }

         public Criteria andUserPasswordEqualTo(String value) {
             addCriterion("USER_PASSWORD =", value, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserPasswordNotEqualTo(String value) {
             addCriterion("USER_PASSWORD <>", value, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserPasswordGreaterThan(String value) {
             addCriterion("USER_PASSWORD >", value, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserPasswordGreaterThanOrEqualTo(String value) {
             addCriterion("USER_PASSWORD >=", value, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserPasswordLessThan(String value) {
             addCriterion("USER_PASSWORD <", value, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserPasswordLessThanOrEqualTo(String value) {
             addCriterion("USER_PASSWORD <=", value, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserPasswordLike(String value) {
             addCriterion("USER_PASSWORD like", value, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserPasswordNotLike(String value) {
             addCriterion("USER_PASSWORD not like", value, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserPasswordIn(List<String> values) {
             addCriterion("USER_PASSWORD in", values, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserPasswordNotIn(List<String> values) {
             addCriterion("USER_PASSWORD not in", values, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserPasswordBetween(String value1, String value2) {
             addCriterion("USER_PASSWORD between", value1, value2, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserPasswordNotBetween(String value1, String value2) {
             addCriterion("USER_PASSWORD not between", value1, value2, "userPassword");
             return (Criteria) this;
         }

         public Criteria andUserEmailIsNull() {
             addCriterion("USER_EMAIL is null");
             return (Criteria) this;
         }

         public Criteria andUserEmailIsNotNull() {
             addCriterion("USER_EMAIL is not null");
             return (Criteria) this;
         }

         public Criteria andUserEmailEqualTo(String value) {
             addCriterion("USER_EMAIL =", value, "userEmail");
             return (Criteria) this;
         }

         public Criteria andUserEmailNotEqualTo(String value) {
             addCriterion("USER_EMAIL <>", value, "userEmail");
             return (Criteria) this;
         }

         public Criteria andUserEmailGreaterThan(String value) {
             addCriterion("USER_EMAIL >", value, "userEmail");
             return (Criteria) this;
         }

         public Criteria andUserEmailGreaterThanOrEqualTo(String value) {
             addCriterion("USER_EMAIL >=", value, "userEmail");
             return (Criteria) this;
         }

         public Criteria andUserEmailLessThan(String value) {
             addCriterion("USER_EMAIL <", value, "userEmail");
             return (Criteria) this;
         }

         public Criteria andUserEmailLessThanOrEqualTo(String value) {
             addCriterion("USER_EMAIL <=", value, "userEmail");
             return (Criteria) this;
         }

         public Criteria andUserEmailLike(String value) {
             addCriterion("USER_EMAIL like", value, "userEmail");
             return (Criteria) this;
         }

         public Criteria andUserEmailNotLike(String value) {
             addCriterion("USER_EMAIL not like", value, "userEmail");
             return (Criteria) this;
         }

         public Criteria andUserEmailIn(List<String> values) {
             addCriterion("USER_EMAIL in", values, "userEmail");
             return (Criteria) this;
         }

         public Criteria andUserEmailNotIn(List<String> values) {
             addCriterion("USER_EMAIL not in", values, "userEmail");
             return (Criteria) this;
         }

         public Criteria andUserEmailBetween(String value1, String value2) {
             addCriterion("USER_EMAIL between", value1, value2, "userEmail");
             return (Criteria) this;
         }

         public Criteria andUserEmailNotBetween(String value1, String value2) {
             addCriterion("USER_EMAIL not between", value1, value2, "userEmail");
             return (Criteria) this;
         }
     }

     /**
      * This class was generated by MyBatis Generator.
      * This class corresponds to the database table t_user
      *
      * @mbggenerated do_not_delete_during_merge
      */
     public static class Criteria extends GeneratedCriteria {

         protected Criteria() {
             super();
         }
     }

     /**
      * This class was generated by MyBatis Generator.
      * This class corresponds to the database table t_user
      *
      * @mbggenerated
      */
     public static class Criterion {
         private String condition;

         private Object value;

         private Object secondValue;

         private boolean noValue;

         private boolean singleValue;

         private boolean betweenValue;

         private boolean listValue;

         public String getCondition() {
             return condition;
         }

         public Object getValue() {
             return value;
         }

         public Object getSecondValue() {
             return secondValue;
         }

         public boolean isNoValue() {
             return noValue;
         }

         public boolean isSingleValue() {
             return singleValue;
         }

         public boolean isBetweenValue() {
             return betweenValue;
         }

         public boolean isListValue() {
             return listValue;
         }

         protected Criterion(String condition) {
             super();
             this.condition = condition;
             this.noValue = true;
         }

         protected Criterion(String condition, Object value) {
             super();
             this.condition = condition;
             this.value = value;
             if (value instanceof List<?>) {
                 this.listValue = true;
             } else {
                 this.singleValue = true;
             }
         }

         protected Criterion(String condition, Object value, Object secondValue) {
             super();
             this.condition = condition;
             this.value = value;
             this.secondValue = secondValue;
             this.betweenValue = true;
         }
     }
 }

（2）dao层文件。它自动取名为UserMapper.java，可以自己手动写成UserDao.java

 package com.lin.dao;

 import com.lin.domain.User;
 import com.lin.domain.UserExample;
 import java.util.List;
 import org.apache.ibatis.annotations.Param;

 public interface UserMapper {
     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     int countByExample(UserExample example);

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     int deleteByExample(UserExample example);

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     int deleteByPrimaryKey(Integer userId);

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     int insert(User record);

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     int insertSelective(User record);

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     List<User> selectByExample(UserExample example);

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     User selectByPrimaryKey(Integer userId);

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     int updateByExampleSelective(@Param("record") User record, @Param("example") UserExample example);

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     int updateByExample(@Param("record") User record, @Param("example") UserExample example);

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     int updateByPrimaryKeySelective(User record);

     /**
      * This method was generated by MyBatis Generator.
      * This method corresponds to the database table t_user
      *
      * @mbggenerated
      */
     int updateByPrimaryKey(User record);
 }

(3)Mapper.xml文件：

 <?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.lin.dao.UserMapper" >
   <resultMap id="BaseResultMap" type="com.lin.domain.User" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     <id column="USER_ID" property="userId" jdbcType="INTEGER" />
     <result column="USER_NAME" property="userName" jdbcType="CHAR" />
     <result column="USER_PASSWORD" property="userPassword" jdbcType="CHAR" />
     <result column="USER_EMAIL" property="userEmail" jdbcType="CHAR" />
   </resultMap>
   <sql id="Example_Where_Clause" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     <where >
       <foreach collection="oredCriteria" item="criteria" separator="or" >
         <if test="criteria.valid" >
           <trim prefix="(" suffix=")" prefixOverrides="and" >
             <foreach collection="criteria.criteria" item="criterion" >
               <choose >
                 <when test="criterion.noValue" >
                   and ${criterion.condition}
                 </when>
                 <when test="criterion.singleValue" >
                   and ${criterion.condition} #{criterion.value}
                 </when>
                 <when test="criterion.betweenValue" >
                   and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                 </when>
                 <when test="criterion.listValue" >
                   and ${criterion.condition}
                   <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                     #{listItem}
                   </foreach>
                 </when>
               </choose>
             </foreach>
           </trim>
         </if>
       </foreach>
     </where>
   </sql>
   <sql id="Update_By_Example_Where_Clause" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     <where >
       <foreach collection="example.oredCriteria" item="criteria" separator="or" >
         <if test="criteria.valid" >
           <trim prefix="(" suffix=")" prefixOverrides="and" >
             <foreach collection="criteria.criteria" item="criterion" >
               <choose >
                 <when test="criterion.noValue" >
                   and ${criterion.condition}
                 </when>
                 <when test="criterion.singleValue" >
                   and ${criterion.condition} #{criterion.value}
                 </when>
                 <when test="criterion.betweenValue" >
                   and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                 </when>
                 <when test="criterion.listValue" >
                   and ${criterion.condition}
                   <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                     #{listItem}
                   </foreach>
                 </when>
               </choose>
             </foreach>
           </trim>
         </if>
       </foreach>
     </where>
   </sql>
   <sql id="Base_Column_List" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     USER_ID, USER_NAME, USER_PASSWORD, USER_EMAIL
   </sql>
   <select id="selectByExample" resultMap="BaseResultMap" parameterType="com.lin.domain.UserExample" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     select
     <if test="distinct" >
       distinct
     </if>
     <include refid="Base_Column_List" />
     from t_user
     <if test="_parameter != null" >
       <include refid="Example_Where_Clause" />
     </if>
     <if test="orderByClause != null" >
       order by ${orderByClause}
     </if>
   </select>
   <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     select
     <include refid="Base_Column_List" />
     from t_user
     where USER_ID = #{userId,jdbcType=INTEGER}
   </select>
   <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     delete from t_user
     where USER_ID = #{userId,jdbcType=INTEGER}
   </delete>
   <delete id="deleteByExample" parameterType="com.lin.domain.UserExample" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     delete from t_user
     <if test="_parameter != null" >
       <include refid="Example_Where_Clause" />
     </if>
   </delete>
   <insert id="insert" parameterType="com.lin.domain.User" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     insert into t_user (USER_ID, USER_NAME, USER_PASSWORD,
       USER_EMAIL)
     values (#{userId,jdbcType=INTEGER}, #{userName,jdbcType=CHAR}, #{userPassword,jdbcType=CHAR},
       #{userEmail,jdbcType=CHAR})
   </insert>
   <insert id="insertSelective" parameterType="com.lin.domain.User" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     insert into t_user
     <trim prefix="(" suffix=")" suffixOverrides="," >
       <if test="userId != null" >
         USER_ID,
       </if>
       <if test="userName != null" >
         USER_NAME,
       </if>
       <if test="userPassword != null" >
         USER_PASSWORD,
       </if>
       <if test="userEmail != null" >
         USER_EMAIL,
       </if>
     </trim>
     <trim prefix="values (" suffix=")" suffixOverrides="," >
       <if test="userId != null" >
         #{userId,jdbcType=INTEGER},
       </if>
       <if test="userName != null" >
         #{userName,jdbcType=CHAR},
       </if>
       <if test="userPassword != null" >
         #{userPassword,jdbcType=CHAR},
       </if>
       <if test="userEmail != null" >
         #{userEmail,jdbcType=CHAR},
       </if>
     </trim>
   </insert>
   <select id="countByExample" parameterType="com.lin.domain.UserExample" resultType="java.lang.Integer" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     select count(*) from t_user
     <if test="_parameter != null" >
       <include refid="Example_Where_Clause" />
     </if>
   </select>
   <update id="updateByExampleSelective" parameterType="map" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     update t_user
     <set >
       <if test="record.userId != null" >
         USER_ID = #{record.userId,jdbcType=INTEGER},
       </if>
       <if test="record.userName != null" >
         USER_NAME = #{record.userName,jdbcType=CHAR},
       </if>
       <if test="record.userPassword != null" >
         USER_PASSWORD = #{record.userPassword,jdbcType=CHAR},
       </if>
       <if test="record.userEmail != null" >
         USER_EMAIL = #{record.userEmail,jdbcType=CHAR},
       </if>
     </set>
     <if test="_parameter != null" >
       <include refid="Update_By_Example_Where_Clause" />
     </if>
   </update>
   <update id="updateByExample" parameterType="map" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     update t_user
     set USER_ID = #{record.userId,jdbcType=INTEGER},
       USER_NAME = #{record.userName,jdbcType=CHAR},
       USER_PASSWORD = #{record.userPassword,jdbcType=CHAR},
       USER_EMAIL = #{record.userEmail,jdbcType=CHAR}
     <if test="_parameter != null" >
       <include refid="Update_By_Example_Where_Clause" />
     </if>
   </update>
   <update id="updateByPrimaryKeySelective" parameterType="com.lin.domain.User" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     update t_user
     <set >
       <if test="userName != null" >
         USER_NAME = #{userName,jdbcType=CHAR},
       </if>
       <if test="userPassword != null" >
         USER_PASSWORD = #{userPassword,jdbcType=CHAR},
       </if>
       <if test="userEmail != null" >
         USER_EMAIL = #{userEmail,jdbcType=CHAR},
       </if>
     </set>
     where USER_ID = #{userId,jdbcType=INTEGER}
   </update>
   <update id="updateByPrimaryKey" parameterType="com.lin.domain.User" >
     <!--
       WARNING - @mbggenerated
       This element is automatically generated by MyBatis Generator, do not modify.
     -->
     update t_user
     set USER_NAME = #{userName,jdbcType=CHAR},
       USER_PASSWORD = #{userPassword,jdbcType=CHAR},
       USER_EMAIL = #{userEmail,jdbcType=CHAR}
     where USER_ID = #{userId,jdbcType=INTEGER}
   </update>
 </mapper>

这样就好了，serivce层的文件自己再去写写就好了。

如果不想要UserExample文件怎么办呢？

那就把

 <table schema="general" tableName="T_USER" domainObjectName="User">
  <!--domain字段的命名规则，false:默认为驼峰命名 true:按数据库真实命名  -->
 <property name="useActualColumnNames" value="false"/>
 </table>

换成：

 <table schema="general" tableName="T_USER" domainObjectName="User" enableCountByExample="false" enableUpdateByExample="false"
        enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false">
  <!--domain字段的命名规则，false:默认为驼峰命名 true:按数据库真实命名  -->
 <property name="useActualColumnNames" value="false"/>
 </table>

这样就可以了
2、java代码读取xml文件生成

首先要导入如下的包：

然后在工程里写一个文件如下：

 package Test;
 import java.io.File;
 import java.io.IOException;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;

 import org.mybatis.generator.api.MyBatisGenerator;
 import org.mybatis.generator.config.Configuration;
 import org.mybatis.generator.config.xml.ConfigurationParser;
 import org.mybatis.generator.exception.InvalidConfigurationException;
 import org.mybatis.generator.exception.XMLParserException;
 import org.mybatis.generator.internal.DefaultShellCallback;
 public class BuildFile {
     public static void main(String[] args) throws InvalidConfigurationException, IOException, XMLParserException, SQLException, InterruptedException {
         List<String> warnings = new ArrayList<String>();
           boolean overwrite = true;
           File configFile = new File("D:\\lunaJee-workspace\\MyBatisLearningChapter7\\src\\generator.xml");  //输入绝对路径
           ConfigurationParser cp = new ConfigurationParser(warnings);
           Configuration config=null;
           config = cp.parseConfiguration(configFile);
           DefaultShellCallback callback = new DefaultShellCallback(overwrite);
           MyBatisGenerator myBatisGenerator = null;
           myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
           myBatisGenerator.generate(null);
     }
 }

然后运行，再刷新下就可以了