介绍

Mybatis Generator(MBG)是Mybatis的一个代码生成工具。MBG解决了对数据库操作有最大影响的一些CRUD操作，很大程度上提升开发效率。如果需要联合查询仍然需要手写sql。相信很多人都听说过微服务，各个微服务之间是松耦合的。每个微服务仅关注于完成一件任务并很好地完成该任务。在一个微服务的开发过程中很可能只关注对单表的操作。所以MBG在开发过程中可以快速的生成代码提升开发效率。

本文将说到在springboot的项目中如何去配置（XML形式和Java配置类形式）和使用MBG以及MBG生成代码的两种方式（XML形式和注解形式），在springboot中更推荐去使用注解的形式。

MBG配置

1. 添加依赖

            
     
      org.mybatis.generator
             
     
      mybatis-generator-core
             
     
      1.3.5
         
    

2.XML配置

配置示例：在新建springboot项目的根目录下创建mbg.xml文件。

配置详解

生成代码：

public class TestMGB {    public static void main(String[] args) throws IOException, XMLParserException, InvalidConfigurationException, SQLException, InterruptedException {        List
    
      warnings =new ArrayList
     
      ();        boolean overwrite=true;        File configFile=new File("mgb.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);    }}
     
    

3.Java配置示例

package com.mgb.test;import java.util.ArrayList;import java.util.List;import org.mybatis.generator.api.MyBatisGenerator;import org.mybatis.generator.config.CommentGeneratorConfiguration;import org.mybatis.generator.config.Configuration;import org.mybatis.generator.config.Context;import org.mybatis.generator.config.JDBCConnectionConfiguration;import org.mybatis.generator.config.JavaClientGeneratorConfiguration;import org.mybatis.generator.config.JavaModelGeneratorConfiguration;import org.mybatis.generator.config.JavaTypeResolverConfiguration;import org.mybatis.generator.config.ModelType;import org.mybatis.generator.config.PluginConfiguration;import org.mybatis.generator.config.SqlMapGeneratorConfiguration;import org.mybatis.generator.config.TableConfiguration;import org.mybatis.generator.internal.DefaultShellCallback;public class MGBConfig {    public static void main(String[] args) throws Exception{         //配置xml配置项         List
    
      warnings = new ArrayList
     
      ();         boolean overwrite = true;         Configuration config = new Configuration();         Context context = new Context(ModelType.CONDITIONAL);         context.setTargetRuntime("MyBatis3");         context.setId("defaultContext");                 //自动识别数据库关键字，默认false，如果设置为true，        //根据SqlReservedWords中定义的关键字列表；一般保留默认值，遇到数据库关键字（Java关键字），        //使用columnOverride覆盖         context.addProperty("autoDelimitKeywords","true");                 //生成的Java文件的编码        context.addProperty("javaFileEncoding","utf-8");        context.addProperty("beginningDelimiter","`");        context.addProperty("endingDelimiter","`");        //格式化java代码        context.addProperty("javaFormatter","org.mybatis.generator.api.dom.DefaultJavaFormatter");        //格式化xml代码        context.addProperty("xmlFormatter","org.mybatis.generator.api.dom.DefaultXmlFormatter");        //格式化信息        PluginConfiguration pluginConfiguration = new PluginConfiguration();        pluginConfiguration.setConfigurationType("org.mybatis.generator.plugins.SerializablePlugin");        pluginConfiguration.setConfigurationType("org.mybatis.generator.plugins.ToStringPlugin");        context.addPluginConfiguration(pluginConfiguration);                //设置是否去除生成注释        CommentGeneratorConfiguration commentGeneratorConfiguration = new CommentGeneratorConfiguration();        commentGeneratorConfiguration.addProperty("suppressAllComments","true");        //commentGeneratorConfiguration.addProperty("suppressDate","true");        context.setCommentGeneratorConfiguration(commentGeneratorConfiguration);            //设置连接数据库        JDBCConnectionConfiguration jdbcConnectionConfiguration = new JDBCConnectionConfiguration();        jdbcConnectionConfiguration.setDriverClass("com.mysql.jdbc.Driver");        jdbcConnectionConfiguration.setConnectionURL("jdbc:mysql://localhost:3306/definesys");        jdbcConnectionConfiguration.setPassword("welcome1");        jdbcConnectionConfiguration.setUserId("root");        context.setJdbcConnectionConfiguration(jdbcConnectionConfiguration);                JavaTypeResolverConfiguration javaTypeResolverConfiguration = new JavaTypeResolverConfiguration();        //是否使用bigDecimal， false可自动转化以下类型（Long, Integer, Short, etc.）        javaTypeResolverConfiguration.addProperty("forceBigDecimals","false");        context.setJavaTypeResolverConfiguration(javaTypeResolverConfiguration);                //生成实体类的地址        JavaModelGeneratorConfiguration javaModelGeneratorConfiguration = new JavaModelGeneratorConfiguration();        javaModelGeneratorConfiguration.setTargetPackage("com.mgb.domain");        javaModelGeneratorConfiguration.setTargetProject("src/main/java");        javaModelGeneratorConfiguration.addProperty("enableSubPackages","true");        javaModelGeneratorConfiguration.addProperty("trimStrings","true");        context.setJavaModelGeneratorConfiguration(javaModelGeneratorConfiguration);                //生成的xml的地址        SqlMapGeneratorConfiguration sqlMapGeneratorConfiguration = new SqlMapGeneratorConfiguration();        sqlMapGeneratorConfiguration.setTargetProject("src/main/java");        sqlMapGeneratorConfiguration.setTargetPackage("com.mgb.mapper");        sqlMapGeneratorConfiguration.addProperty("enableSubPackages","true");        context.setSqlMapGeneratorConfiguration(sqlMapGeneratorConfiguration);                //生成注解接口        JavaClientGeneratorConfiguration javaClientGeneratorConfiguration = new JavaClientGeneratorConfiguration();        javaClientGeneratorConfiguration.setTargetPackage("com.mgb.dao");        javaClientGeneratorConfiguration.setTargetProject("src/main/java");        //注解形式 ANNOTATEDMAPPER  xml形式 XMLMAPPER        javaClientGeneratorConfiguration.setConfigurationType("ANNOTATEDMAPPER");        javaClientGeneratorConfiguration.addProperty("enableSubPackages","true");        context.setJavaClientGeneratorConfiguration(javaClientGeneratorConfiguration);                TableConfiguration tableConfiguration = new TableConfiguration(context);        tableConfiguration.setTableName("user_info");        tableConfiguration.setCountByExampleStatementEnabled(true);        tableConfiguration.setUpdateByExampleStatementEnabled(true);        tableConfiguration.setDeleteByExampleStatementEnabled(true);        tableConfiguration.setInsertStatementEnabled(true);        tableConfiguration.setDeleteByPrimaryKeyStatementEnabled(true);                context.addTableConfiguration(tableConfiguration);                config.addContext(context);        DefaultShellCallback callback = new DefaultShellCallback(overwrite);        MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);        myBatisGenerator.generate(null);    }    }
     
    

使用

package com.mgb.service;import java.util.List;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import com.mgb.dao.UserInfoMapper;import com.mgb.domain.UserInfo;import com.mgb.domain.UserInfoExample;@Servicepublic class UserService {    @Autowired    private UserInfoMapper userInfoMapper;        /**     * 按姓名查询     * @param name     * @return     */    public List
    
      getUserByName(String name){        UserInfoExample uerInfoExample=new UserInfoExample();        uerInfoExample.createCriteria().andNameEqualTo(name);        return userInfoMapper.selectByExample(uerInfoExample);    }        /**     * 有条件的insert     * @param userInfo     * @return     */    public Integer addUser(UserInfo userInfo) {        return userInfoMapper.insertSelective(userInfo);    }        /**     * 根据ID更新用户信息     * @param userInfo     * @return     */    public Integer updateUser(UserInfo userInfo) {        return userInfoMapper.updateByPrimaryKey(userInfo);    }        /**     * 根据ID删除用户     * @param id     * @return     */    public Integer deleteUserById(Integer id) {        return userInfoMapper.deleteByPrimaryKey(id);    }}