数据库表反向生成(一) MyBatis-generator与IDEA的集成

在Dao层，通过数据库表反向生成，可以节省我们很多的精力，把更多的精力投入复杂的业务中。

数据库表反向生成，指的是通过数据库如mysql中的库表schema生成dao层读写表的基础代码，包括model(entity)和dao(mapper)。

在本文中我先介绍java中mybatis-generator的反向生成。我们在下一篇文章中会介绍django中ORM的反向生成。

mybatis-generator的反向生成有两种方式

1）源码打包生成mybatis-generator.jar，通过执行jar来生成代码，然后把代码拷贝到工程

2）直接跟编辑器集成，例如IDEA。

我们只说明第二种方式。

1、在IDEA中创建一个maven工程

2、在maven工程的pom文件中添加mybatis-generator-maven-plugin插件

<build>
        <plugins>
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.2</version>
                <configuration>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                </configuration>
            </plugin>
        </plugins>
    </build>

3、在src/main/resources目录下创建两个配置文件，generatorConfig.xml和generator.properties

generatorConfig.xml文件

内容请看注释，<table>中配置的是你要扫描的表。

<?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>
    <!--导入属性配置 -->
    <properties resource="generator.properties"></properties>

    <!--指定特定数据库的jdbc驱动jar包的位置 -->
    <classPathEntry location="${jdbc.driverLocation}"/>

    <context id="default" targetRuntime="MyBatis3">

        <!-- optional，旨在创建class时，对注释进行控制 -->
        <commentGenerator>
            <property name="suppressDate" value="true" />
        </commentGenerator>

        <!--jdbc的数据库连接 -->
        <jdbcConnection driverClass="${jdbc.driverClass}" connectionURL="${jdbc.connectionURL}" userId="${jdbc.userId}" password="${jdbc.password}">
        </jdbcConnection>

        <!-- 非必需，类型处理器，在数据库类型和java类型之间的转换控制-->
        <javaTypeResolver >
            <property name="forceBigDecimals" value="false" />
        </javaTypeResolver>

        <!-- Model模型生成器,用来生成含有主键key的类，记录类 以及查询Example类
            targetPackage     指定生成的model生成所在的包名
            targetProject     指定在该项目下所在的路径
        -->
        <javaModelGenerator targetPackage="com.xiaoju.dqa.jazz.dao.model" targetProject="src/main/java">
            <!-- 是否对model添加 构造函数 -->
            <property name="constructorBased" value="true"/>

            <!-- 是否允许子包，即targetPackage.schemaName.tableName -->
            <property name="enableSubPackages" value="false"/>

            <!-- 建立的Model对象是否 不可改变  即生成的Model对象不会有 setter方法，只有构造方法 -->
            <property name="immutable" value="true"/>

            <!-- 是否对类CHAR类型的列的数据进行trim操作 -->
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <!--Mapper映射文件生成所在的目录 为每一个数据库的表生成对应的SqlMap文件 -->
        <sqlMapGenerator targetPackage="mybatis-mapper" targetProject="src/main/resources">
            <property name="enableSubPackages" value="false"/>
        </sqlMapGenerator>

        <!-- 客户端代码，生成易于使用的针对Model对象和XML配置文件 的代码
                type="ANNOTATEDMAPPER",生成Java Model 和基于注解的Mapper对象
                type="MIXEDMAPPER",生成基于注解的Java Model 和相应的Mapper对象
                type="XMLMAPPER",生成SQLMap XML文件和独立的Mapper接口
        -->
        <javaClientGenerator targetPackage="com.xiaoju.dqa.jazz.dao.mapper" targetProject="src/main/java" type="MIXEDMAPPER">
            <property name="enableSubPackages" value=""/>
            <!--
                    定义Maper.java 源代码中的ByExample() 方法的可视性，可选的值有：
                    public;
                    private;
                    protected;
                    default
                    注意：如果 targetRuntime="MyBatis3",此参数被忽略
             -->
            <property name="exampleMethodVisibility" value=""/>
            <!--
                                           方法名计数器
              Important note: this property is ignored if the target runtime is MyBatis3.
             -->
            <property name="methodNameCalculator" value=""/>

            <!--
                                                为生成的接口添加父接口
             -->
            <property name="rootInterface" value=""/>

        </javaClientGenerator>

        <table tableName="hiveTable" domainObjectName="HiveTable"
               enableCountByExample="false" enableUpdateByExample="false"
               enableDeleteByExample="false" enableSelectByExample="false"
               selectByExampleQueryId="false">
        </table>

        <table tableName="hiveLocation" domainObjectName="HiveLocation"
               enableCountByExample="false" enableUpdateByExample="false"
               enableDeleteByExample="false" enableSelectByExample="false"
               selectByExampleQueryId="false">
        </table>

    </context>
</generatorConfiguration>

generator.properties文件

这个主要配置的是你的驱动程序和数据库链接，mybatis将去配置的数据库中扫描要生成的表。

jdbc.driverLocation=/Users/didi/.m2/repository/mysql/mysql-connector-java/5.1.40/mysql-connector-java-5.1.40.jar
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.connectionURL=jdbc:mysql://localhost:3306/jazz?useUnicode=true&characterEncoding=utf-8
jdbc.userId=root
jdbc.password=123456

4、在IDEA中添加Run选项，使用mybatis-generator-maven-plugin

配置如下

1）Name写generator会在run菜单生成一个名叫generator的选项；

2）CommandLine写要执行的命令，mybatis-generator:generate  -e

3）working directory写你pom所在的工程，我这里是区分模块开发的，所以在dao模块下。

5、run -> generator执行

这样就会生成对应的代码了

我两张表的建表语句如下：

CREATE TABLE `hiveTable` (
  `id` int(100) NOT NULL AUTO_INCREMENT COMMENT '库表唯一Id',
  `dbName` VARCHAR(100) COMMENT '库名',
  `tableName` VARCHAR(100) COMMENT '表名',
  `location` VARCHAR(500) COMMENT '路径',
  `createTime` DATETIME COMMENT '创建时间',
  `updateTime` DATETIME COMMENT '更新时间',
   PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

CREATE TABLE `hiveLocation` (
  `id` int(100) NOT NULL AUTO_INCREMENT COMMENT '路径唯一Id',
  `location` VARCHAR(500) COMMENT '路径',
  `size` INT(10) COMMENT '大小',
  `createTime` DATETIME COMMENT '创建时间',
  `updateTime` DATETIME COMMENT '更新时间',
   PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

生成的代码如图

我们展示一些生成的代码：

HiveTable.java

package com.xiaoju.dqa.jazz.dao.model;

import java.util.Date;

public class HiveTable {
    /**
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column hiveTable.id
     *
     * @mbggenerated
     */
    private Integer id;

    /**
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column hiveTable.dbName
     *
     * @mbggenerated
     */
    private String dbname;

    /**
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column hiveTable.tableName
     *
     * @mbggenerated
     */
    private String tablename;

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

    /**
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column hiveTable.createTime
     *
     * @mbggenerated
     */
    private Date createtime;

    /**
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column hiveTable.updateTime
     *
     * @mbggenerated
     */
    private Date updatetime;

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table hiveTable
     *
     * @mbggenerated
     */
    public HiveTable(Integer id, String dbname, String tablename, String location, Date createtime, Date updatetime) {
        this.id = id;
        this.dbname = dbname;
        this.tablename = tablename;
        this.location = location;
        this.createtime = createtime;
        this.updatetime = updatetime;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method returns the value of the database column hiveTable.id
     *
     * @return the value of hiveTable.id
     *
     * @mbggenerated
     */
    public Integer getId() {
        return id;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method returns the value of the database column hiveTable.dbName
     *
     * @return the value of hiveTable.dbName
     *
     * @mbggenerated
     */
    public String getDbname() {
        return dbname;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method returns the value of the database column hiveTable.tableName
     *
     * @return the value of hiveTable.tableName
     *
     * @mbggenerated
     */
    public String getTablename() {
        return tablename;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method returns the value of the database column hiveTable.location
     *
     * @return the value of hiveTable.location
     *
     * @mbggenerated
     */
    public String getLocation() {
        return location;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method returns the value of the database column hiveTable.createTime
     *
     * @return the value of hiveTable.createTime
     *
     * @mbggenerated
     */
    public Date getCreatetime() {
        return createtime;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method returns the value of the database column hiveTable.updateTime
     *
     * @return the value of hiveTable.updateTime
     *
     * @mbggenerated
     */
    public Date getUpdatetime() {
        return updatetime;
    }
}

HiveTableMapper.java

package com.xiaoju.dqa.jazz.dao.mapper;

import com.xiaoju.dqa.jazz.dao.model.HiveTable;
import org.apache.ibatis.annotations.*;

@Mapper
public interface HiveTableMapper {
    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table hiveTable
     *
     * @mbggenerated
     */
    @Delete({
        "delete from hiveTable",
        "where id = #{id,jdbcType=INTEGER}"
    })
    int deleteByPrimaryKey(Integer id);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table hiveTable
     *
     * @mbggenerated
     */
    @Insert({
        "insert into hiveTable (id, dbName, ",
        "tableName, location, ",
        "createTime, updateTime)",
        "values (#{id,jdbcType=INTEGER}, #{dbname,jdbcType=VARCHAR}, ",
        "#{tablename,jdbcType=VARCHAR}, #{location,jdbcType=VARCHAR}, ",
        "#{createtime,jdbcType=TIMESTAMP}, #{updatetime,jdbcType=TIMESTAMP})"
    })
    int insert(HiveTable record);

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

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table hiveTable
     *
     * @mbggenerated
     */
    @Select({
        "select",
        "id, dbName, tableName, location, createTime, updateTime",
        "from hiveTable",
        "where id = #{id,jdbcType=INTEGER}"
    })
    @ResultMap("BaseResultMap")
    HiveTable selectByPrimaryKey(Integer id);

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

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table hiveTable
     *
     * @mbggenerated
     */
    @Update({
        "update hiveTable",
        "set dbName = #{dbname,jdbcType=VARCHAR},",
          "tableName = #{tablename,jdbcType=VARCHAR},",
          "location = #{location,jdbcType=VARCHAR},",
          "createTime = #{createtime,jdbcType=TIMESTAMP},",
          "updateTime = #{updatetime,jdbcType=TIMESTAMP}",
        "where id = #{id,jdbcType=INTEGER}"
    })
    int updateByPrimaryKey(HiveTable record);
}

HiveTableMapper.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="com.xiaoju.dqa.jazz.dao.mapper.HiveTableMapper" >
  <resultMap id="BaseResultMap" type="com.xiaoju.dqa.jazz.dao.model.HiveTable" >
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    <constructor >
      <idArg column="id" jdbcType="INTEGER" javaType="java.lang.Integer" />
      <arg column="dbName" jdbcType="VARCHAR" javaType="java.lang.String" />
      <arg column="tableName" jdbcType="VARCHAR" javaType="java.lang.String" />
      <arg column="location" jdbcType="VARCHAR" javaType="java.lang.String" />
      <arg column="createTime" jdbcType="TIMESTAMP" javaType="java.util.Date" />
      <arg column="updateTime" jdbcType="TIMESTAMP" javaType="java.util.Date" />
    </constructor>
  </resultMap>
  <sql id="Base_Column_List" >
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    id, dbName, tableName, location, createTime, updateTime
  </sql>
  <insert id="insertSelective" parameterType="com.xiaoju.dqa.jazz.dao.model.HiveTable" >
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    insert into hiveTable
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        id,
      </if>
      <if test="dbname != null" >
        dbName,
      </if>
      <if test="tablename != null" >
        tableName,
      </if>
      <if test="location != null" >
        location,
      </if>
      <if test="createtime != null" >
        createTime,
      </if>
      <if test="updatetime != null" >
        updateTime,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        #{id,jdbcType=INTEGER},
      </if>
      <if test="dbname != null" >
        #{dbname,jdbcType=VARCHAR},
      </if>
      <if test="tablename != null" >
        #{tablename,jdbcType=VARCHAR},
      </if>
      <if test="location != null" >
        #{location,jdbcType=VARCHAR},
      </if>
      <if test="createtime != null" >
        #{createtime,jdbcType=TIMESTAMP},
      </if>
      <if test="updatetime != null" >
        #{updatetime,jdbcType=TIMESTAMP},
      </if>
    </trim>
  </insert>
  <update id="updateByPrimaryKeySelective" parameterType="com.xiaoju.dqa.jazz.dao.model.HiveTable" >
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    update hiveTable
    <set >
      <if test="dbname != null" >
        dbName = #{dbname,jdbcType=VARCHAR},
      </if>
      <if test="tablename != null" >
        tableName = #{tablename,jdbcType=VARCHAR},
      </if>
      <if test="location != null" >
        location = #{location,jdbcType=VARCHAR},
      </if>
      <if test="createtime != null" >
        createTime = #{createtime,jdbcType=TIMESTAMP},
      </if>
      <if test="updatetime != null" >
        updateTime = #{updatetime,jdbcType=TIMESTAMP},
      </if>
    </set>
    where id = #{id,jdbcType=INTEGER}
  </update>
</mapper>

想让xml文件生效，你可以在创建数据源的时候加入xml文件的路径

例如其中的bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis-mapper/*.xml"));

package com.xiaoju.dqa.jazz.dao.configuration;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.xiaoju.dqa.jazz.dao.mapper", sqlSessionTemplateRef  = "jazzSqlSessionTemplate")
public class JazzDataSource {

    @Bean(name = "jazzData")
    @ConfigurationProperties(prefix = "spring.datasource.jazz")
    @Primary
    public DataSource jazzData() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "jazzSqlSessionFactory")
    @Primary
    public SqlSessionFactory jazzSqlSessionFactory(@Qualifier("jazzData") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis-mapper/*.xml"));
        return bean.getObject();
    }

    @Bean(name = "jazzTransactionManager")
    @Primary
    public DataSourceTransactionManager jazzTransactionManager(@Qualifier("jazzData") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "jazzSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate jazzSqlSessionTemplate(@Qualifier("jazzSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}