摘要：每個微服務(wù)僅關(guān)注于完成一件任務(wù)并很好地完成該任務(wù)。在一個微服務(wù)的開發(fā)過程中很可能只關(guān)注對單表的操作。本文將說到在的項目中如何去配置形式和配置類形式和使用以及生成代碼的兩種方式形式和注解形式，在中更推薦去使用注解的形式。

Mybatis Generator(MBG)是Mybatis的一個代碼生成工具。MBG解決了對數(shù)據(jù)庫操作有最大影響的一些CRUD操作，很大程度上提升開發(fā)效率。如果需要聯(lián)合查詢?nèi)匀恍枰謱憇ql。相信很多人都聽說過微服務(wù)，各個微服務(wù)之間是松耦合的。每個微服務(wù)僅關(guān)注于完成一件任務(wù)并很好地完成該任務(wù)。在一個微服務(wù)的開發(fā)過程中很可能只關(guān)注對單表的操作。所以MBG在開發(fā)過程中可以快速的生成代碼提升開發(fā)效率。

本文將說到在springboot的項目中如何去配置（XML形式和Java配置類形式）和使用MBG以及MBG生成代碼的兩種方式（XML形式和注解形式），在springboot中更推薦去使用注解的形式。

添加依賴

    
        org.mybatis.generator
        mybatis-generator-core
        1.3.5
    

2.XML配置

配置示例：在新建springboot項目的根目錄下創(chuàng)建mbg.xml文件。

配置詳解

生成代碼：

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
基于Java的配置是和上面的XML配置是相對應(yīng)的。直接運(yùn)行該示例即可生成數(shù)據(jù)表對于的pojo,mapper接口和一個sqlprovider Java類。

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配置項
         List warnings = new ArrayList();
         boolean overwrite = true;
         Configuration config = new Configuration();
         Context context = new Context(ModelType.CONDITIONAL);
         context.setTargetRuntime("MyBatis3");
         context.setId("defaultContext");
         
        //自動識別數(shù)據(jù)庫關(guān)鍵字，默認(rèn)false，如果設(shè)置為true，
        //根據(jù)SqlReservedWords中定義的關(guān)鍵字列表；一般保留默認(rèn)值，遇到數(shù)據(jù)庫關(guān)鍵字（Java關(guān)鍵字），
        //使用columnOverride覆蓋
         context.addProperty("autoDelimitKeywords","true");
         
        //生成的Java文件的編碼
        context.addProperty("javaFileEncoding","utf-8");
        context.addProperty("beginningDelimiter","`");
        context.addProperty("endingDelimiter","`");
        //格式化java代碼
        context.addProperty("javaFormatter","org.mybatis.generator.api.dom.DefaultJavaFormatter");
        //格式化xml代碼
        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);
        
        //設(shè)置是否去除生成注釋
        CommentGeneratorConfiguration commentGeneratorConfiguration = new CommentGeneratorConfiguration();
        commentGeneratorConfiguration.addProperty("suppressAllComments","true");
        //commentGeneratorConfiguration.addProperty("suppressDate","true");
        context.setCommentGeneratorConfiguration(commentGeneratorConfiguration);
    
        //設(shè)置連接數(shù)據(jù)庫
        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可自動轉(zhuǎn)化以下類型（Long, Integer, Short, etc.）
        javaTypeResolverConfiguration.addProperty("forceBigDecimals","false");
        context.setJavaTypeResolverConfiguration(javaTypeResolverConfiguration);
        
        //生成實體類的地址
        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);
    }
    
}

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;

@Service
public class UserService {
    @Autowired
    private UserInfoMapper userInfoMapper;
    
    /**
     * 按姓名查詢
     * @param name
     * @return
     */
    public List getUserByName(String name){
        UserInfoExample uerInfoExample=new UserInfoExample();
        uerInfoExample.createCriteria().andNameEqualTo(name);
        return userInfoMapper.selectByExample(uerInfoExample);
    }
    
    /**
     * 有條件的insert
     * @param userInfo
     * @return
     */
    public Integer addUser(UserInfo userInfo) {
        return userInfoMapper.insertSelective(userInfo);
    }
    
    /**
     * 根據(jù)ID更新用戶信息
     * @param userInfo
     * @return
     */
    public Integer updateUser(UserInfo userInfo) {
        return userInfoMapper.updateByPrimaryKey(userInfo);
    }
    
    /**
     * 根據(jù)ID刪除用戶
     * @param id
     * @return
     */
    public Integer deleteUserById(Integer id) {
        return userInfoMapper.deleteByPrimaryKey(id);
    }

}