mybatis的逆向工程Generator的应用

介绍

众说周知，iBatis是“半自动”ORM。Hibernate可以通过对象关系模型实现对数据库的操作，但是MyBatis只能通过手写SQL来管理对象关系和数据库字段映射。

MyBatis Generator（MBG）是MyBatis的子项目之一，用于自动化创建简单的CURD组件，减少重复性编码工作。

具体介绍http://www.mybatis.org/generator/

使用方式:

MBG支持种5工作方式,这里介绍两种:
1.With Maven
2.With Java
一、这里介绍Maven插件的使用方法
引入Maven插件

<plugin>
    <groupId>org.mybatis.generator</groupId>
    <artifactId>mybatis-generator-maven-plugin</artifactId>
    <version>1.3.5</version>
    <configuration>
        <overwrite>true</overwrite>
        <verbose>true</verbose>
    </configuration>
</plugin>

编辑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>
    <!--导入属性配置-->
    <!--<properties resource="generatorConfig.properties"/>-->
    <!--指定特定数据库的jdbc驱动jar包的位置-->
    <classPathEntry
            location="C:\Users\moun\.m2\repository\mysql\mysql-connector-java\5.1.44\mysql-connector-java-5.1.44.jar"/>
    <context id="default" targetRuntime="MyBatis3" defaultModelType="flat">
        <property name="autoDelimitKeywords" value="true"/>
        <!-- optional，旨在创建class时，对注释进行控制 -->
        <commentGenerator>
            <property name="suppressDate" value="true"/>
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>
        <!--jdbc的数据库连接 -->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                connectionURL="jdbc:mysql://localhost:3306/blog_db?useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=false&amp;useJDBCCompliantTimezoneShift=true&amp;useLegacyDatetimeCode=false&amp;serverTimezone=UTC"
                userId="root"
                password="root" />
        <!--客户端接口生成器，生成针对Model和Mapper的带有iBatis注解的接口文件-->
        <javaClientGenerator targetPackage="antnest.blog.dao.database" targetProject="src/main/java" type="XMLMAPPER" />
        <!--Model模型生成器,用来生成含有主键的实体类以及用于多条件查询Example类-->
        <javaModelGenerator targetPackage="antnest.blog.model.database" targetProject="src/main/java" />
        <!--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="mapper" targetProject="src/main/resources" />

        <!--数据库中表生成类的信息-->
        <table tableName="user"
               enableCountByExample="true" enableUpdateByExample="true"
               enableDeleteByExample="true" enableSelectByExample="true" />
        <table tableName="config"
               enableCountByExample="true" enableUpdateByExample="true"
               enableDeleteByExample="true" enableSelectByExample="true" />
        <!--<table tableName="blog_db.%"
               enableCountByExample="true" enableUpdateByExample="true"
               enableDeleteByExample="true" enableSelectByExample="true" />-->
    </context>
</generatorConfiguration>

运行插件并生成代码

maven插件运行方法:
该项目 右键>>>run as>>>maven build…>>>Goals项输入:mybatis-generator:generate

刷新该项目即可!

二、Java运行方法
引入相关jia包

<dependencies>
  	<dependency>
  		<groupId>mysql</groupId>
  		<artifactId>mysql-connector-java</artifactId>
  		<version>5.1.46</version>
  	</dependency>
  	<dependency>
  		<groupId>org.mybatis.generator</groupId>
  		<artifactId>mybatis-generator-core</artifactId>
  		<version>1.3.5</version>
  	</dependency>
  	<!--  该jar包可以省略 -->
  	<dependency>
  		<groupId>org.mybatis</groupId>
  		<artifactId>mybatis</artifactId>
  		<version>3.4.6</version>
  	</dependency>
  </dependencies>

编辑配置文件mbg.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>
<!-- 指定驱动包 -->
<!--  直接从Maven Dependencies中找到mysql-connector-java的jar包复制出location,如上图 -->
  <classPathEntry location="C:\Users\MSI\.m2\repository\mysql\mysql-connector-java\5.1.46\mysql-connector-java-5.1.46.jar" />
<!-- 指定数据库连接字符串 -->
  <context id="DB2Tables" targetRuntime="MyBatis3">
    <jdbcConnection driverClass="com.mysql.jdbc.Driver"
        connectionURL="jdbc:mysql://localhost:3306/ov"
        userId="root"
        password="root">
    </jdbcConnection>

    <javaTypeResolver >
      <property name="forceBigDecimals" value="false" />
    </javaTypeResolver>
<!-- 指定实体类 -->
<!--  targetPackage="cn.xd.ovls.entity" targetProject=".\src\main\java"根据工程自己指定 -->
    <javaModelGenerator targetPackage="cn.xd.ov.entity" targetProject=".\src\main\java">
      <property name="enableSubPackages" value="true" />
      <property name="trimStrings" value="true" />
    </javaModelGenerator>
<!-- 指定sql定义文件 -->
<!--   targetPackage="sql"  targetProject=".\src\main\resources"根据工程自己指定 -->
    <sqlMapGenerator targetPackage="sql"  targetProject=".\src\main\resources">
      <property name="enableSubPackages" value="true" />
    </sqlMapGenerator>
<!-- 指定Mapper映射器接口type='XMLMAPPER' XML文件定义SQL; type='ANNOTATEDMAPPER' 注解SQL-->
<!--  type类型参考[http://www.mybatis.org/generator/configreference/javaClientGenerator.html](http://www.mybatis.org/generator/configreference/javaClientGenerator.html) -->
<!--  targetPackage="cn.xd.ov.dao"  targetProject=".\src\main\java"根据工程自己指定 -->
    <javaClientGenerator type="ANNOTATEDMAPPER" targetPackage="cn.xd.ov.dao"  targetProject=".\src\main\java">
      <property name="enableSubPackages" value="true" />
    </javaClientGenerator>
<!-- 指定数据表 -->
一、<!--  %可以实现库里的多表生成 -->
    <table tableName="%" 
    	enableCountByExample="false" enableDeleteByExample="false"
    	enableSelectByExample="false" enableUpdateByExample="false">
    </table>
二、指定单表
<table tableName="表名"  domainObjectName="类名"></table>
eg:
<table tableName="USER"  domainObjectName="User"
enableCountByExample="false" enableDeleteByExample="false"
enableSelectByExample="false" enableUpdateByExample="false"></table>
  </context>
</generatorConfiguration>

编写Java启动类RunMyBatisGenerator
编写Java启动类参考http://www.mybatis.org/generator/running/runningWithJava.html

public class RunMyBatisGenerator {

	public static void main(String[] args) throws Exception {
		List<String> warnings = new ArrayList<String>();
		boolean overwrite = true;
		File configFile = new File("mbg.xml");
		ConfigurationParser cp = new ConfigurationParser(warnings);
		Configuration config = cp.parseConfiguration(configFile);
		DefaultShellCallback callback = new DefaultShellCallback(overwrite);
		MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
		myBatisGenerator.generate(null);
	}

}

运行Java类生成实体类


mybatis中的mapper接口文件以及example类的实例函数以及详解
参考:
https://blog.youkuaiyun.com/paincupid/article/details/50921110
https://blog.youkuaiyun.com/biandous/article/details/65630783
https://blog.youkuaiyun.com/luluyo/article/details/81708833
https://blog.youkuaiyun.com/papima/article/details/78577748
https://blog.youkuaiyun.com/yangshangwei/article/details/80140693

原文:https://blog.youkuaiyun.com/acquaintanceship/article/details/78512783