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简介

这一篇我们讲解如何在springboot下整合mybatis-plus，并访问数据库。 MyBatis-Plus（简称 MP）是一个 MyBatis 的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。

对于 mybatis-plus 的使用，可以参照官网，这里我就不讲解了。

一、创建数据库表

DROP TABLE IF EXISTS `tb_employee`;CREATE TABLE `tb_employee` (  `id` int(11) NOT NULL AUTO_INCREMENT,  `lastName` varchar(255) DEFAULT NULL,  `email` varchar(255) DEFAULT NULL,  `gender` int(2) DEFAULT NULL,  `d_id` int(11) DEFAULT NULL,  PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;

二、创建项目

创建一个项目springboot-mybatis

1、pom.xml

    
    	
     
      4.0.0
     	
     
      com.gf
     	
     
      springboot-mybatis
     	
     
      0.0.1-SNAPSHOT
     	
     
      jar
     	
     
      springboot-mybatis
     	
     
      Demo project for Spring Boot
     	
     		
      
       org.springframework.boot
      		
      
       spring-boot-starter-parent
      		
      
       2.1.0.RELEASE
      		
       
      	
     	
     		
      
       UTF-8
      		
      
       UTF-8
      		
      
       1.8
      	
     	
     		
      			
       
        org.springframework.boot
       			
       
        spring-boot-starter-web
       		
      		
      			
       
        mysql
       			
       
        mysql-connector-java
       			
       
        runtime
       		
      		
      			
       
        org.projectlombok
       			
       
        lombok
       			
       
        true
       		
      		
      			
       
        com.baomidou
       			
       
        mybatis-plus-boot-starter
       			
       
        3.0.1
       		
      		
      			
       
        org.apache.velocity
       			
       
        velocity
       			
       
        1.7
       		
      		
      			
       
        org.springframework.boot
       			
       
        spring-boot-starter-test
       			
       
        test
       		
      	
     	
     		
      			
       				
        
         org.springframework.boot
        				
        
         spring-boot-maven-plugin
        			
       		
      	
     
    

2. 代码生成器

AutoGenerator 是 MyBatis-Plus 的代码生成器，通过 AutoGenerator 可以快速生成 Entity、Mapper、Mapper XML、Service、Controller 等各个模块的代码，极大的提升了开发效率。

1. mapper.xml.vm

在resources/templates 下创建 Mapper XML的生成模板

    
    
     #if(${enableCache})    
         
     #end#if(${baseResultMap})    
         
     
      #foreach($field in ${table.fields})#if(${field.keyFlag})##生成主键排在第一位        
      #end#end#foreach($field in ${table.commonFields})##生成公共字段    
      #end#foreach($field in ${table.fields})#if(!${field.keyFlag})##生成普通字段        
      #end#end    
     #end#if(${baseColumnList})    
         
     
      #foreach($field in ${table.commonFields})        ${field.name},#end        ${table.fieldNames}    
     #end
    

2. CodeGenerator

package com.gf.config;import com.baomidou.mybatisplus.annotation.DbType;import com.baomidou.mybatisplus.core.toolkit.StringPool;import com.baomidou.mybatisplus.generator.AutoGenerator;import com.baomidou.mybatisplus.generator.InjectionConfig;import com.baomidou.mybatisplus.generator.config.DataSourceConfig;import com.baomidou.mybatisplus.generator.config.FileOutConfig;import com.baomidou.mybatisplus.generator.config.GlobalConfig;import com.baomidou.mybatisplus.generator.config.PackageConfig;import com.baomidou.mybatisplus.generator.config.StrategyConfig;import com.baomidou.mybatisplus.generator.config.TemplateConfig;import com.baomidou.mybatisplus.generator.config.po.TableInfo;import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;import java.util.ArrayList;import java.util.List;public class CodeGenerator {    public static void main(String[] args) throws InterruptedException {        AutoGenerator mpg = new AutoGenerator();        // 全局配置        GlobalConfig gc = new GlobalConfig();        String projectPath = System.getProperty("user.dir");        gc.setOutputDir(projectPath + "/src/main/java");        gc.setFileOverride(true);        gc.setActiveRecord(true);        gc.setEnableCache(false);// XML 二级缓存        gc.setBaseResultMap(true);// XML ResultMap        gc.setBaseColumnList(true);// XML columList        gc.setOpen(false);        gc.setAuthor("gf");        // 自定义文件命名，注意 %s 会自动填充表实体属性！        gc.setMapperName("%sMapper");        gc.setXmlName("%sMapper");        gc.setServiceName("%sService");        gc.setServiceImplName("%sServiceImpl");        gc.setControllerName("%sController");        mpg.setGlobalConfig(gc);        // 数据源配置        DataSourceConfig dsc = new DataSourceConfig();        dsc.setDbType( DbType.MYSQL);        dsc.setDriverName("com.mysql.jdbc.Driver");        dsc.setUrl("jdbc:mysql://127.0.0.1:3306/test?useSSL=false");        dsc.setUsername("xxxxxx");        dsc.setPassword("xxxxxx");        mpg.setDataSource(dsc);        // 包配置        PackageConfig pc = new PackageConfig();        pc.setParent("com.gf");        pc.setController( "controller");        pc.setEntity( "entity" );        //pc.setModuleName("test");        mpg.setPackageInfo(pc);        // 自定义配置        InjectionConfig cfg = new InjectionConfig() {            @Override            public void initMap() {                // to do nothing            }        };        List
    
      focList = new ArrayList<>();        focList.add(new FileOutConfig("/templates/mapper.xml.vm") {            @Override            public String outputFile(TableInfo tableInfo) {                // 自定义输入文件名称                return projectPath + "/src/main/resources/mapper/"                        + tableInfo.getEntityName() + "Mapper" + StringPool.DOT_XML;            }        });        cfg.setFileOutConfigList(focList);        mpg.setCfg(cfg);        mpg.setTemplate(new TemplateConfig().setXml(null));        // 策略配置        StrategyConfig strategy = new StrategyConfig();        //此处可以修改为您的表前缀        strategy.setTablePrefix(new String[] { "tb_"});        // 表名生成策略        strategy.setNaming(NamingStrategy.underline_to_camel);        // 需要生成的表        strategy.setInclude(new String[] { "tb_employee" });        // 排除生成的表        //strategy.setExclude(new String[]{"test"});        strategy.setEntityLombokModel( true );        mpg.setStrategy(strategy);        // 执行生成        mpg.execute();    }}
    

我运行 CodeGenerator 会发现，我么需要的 entity、mapper、service、controller 都有了，而且mybatis-plus 为我们封装了很对常用的方法 ，大大的提到了我们的开发效率

3. application.properties

spring.datasource.url=jdbc:mysql://localhost:3306/testspring.datasource.username=xxxxxxspring.datasource.password=xxxxxxspring.datasource.driver-class-name=com.mysql.jdbc.Driver

###4. EmployeeController

@RestController@RequestMapping("/employee")public class EmployeeController {    @Autowired    EmployeeService employeeService;    @RequestMapping(value = "/list", method = RequestMethod.GET)    public List
    
      getEmployees() {        return employeeService.list( null );    }    @RequestMapping(value = "/{id}", method = RequestMethod.GET)    public Employee getEmployeeById(@PathVariable("id") int id) {        return employeeService.getById( id );    }    @RequestMapping(value = "/{id}", method = RequestMethod.PUT)    public String updateEmployee(@PathVariable("id") int id, @RequestParam(value = "lastName", required = true) String lastName,                                @RequestParam(value = "email", required = true) String email , @RequestParam(value = "gender", required = true) int gender , @RequestParam(value = "dId", required = true) int dId) {        Employee employee = new Employee();        employee.setId( id );        employee.setLastName( "张" );        employee.setEmail( "zhang@163.com" );        employee.setGender( 1 );        employee.setDId( 1 );        boolean b = employeeService.updateById( employee );        if (b) {            return "update success";        } else {            return "update fail";        }    }    @RequestMapping(value = "/{id}", method = RequestMethod.DELETE)    public String delete(@PathVariable(value = "id")int id) {        boolean b = employeeService.removeById( id );        if(b) {            return "delete success";        }else {            return "delete fail";        }    }    @RequestMapping(value = "", method = RequestMethod.POST)    public String postEmployee(@RequestParam(value = "lastName", required = true) String lastName,                               @RequestParam(value = "email", required = true) String email , @RequestParam(value = "gender", required = true) int gender , @RequestParam(value = "dId", required = true) int dId) {        Employee employee = new Employee();        employee.setLastName( "王" );        employee.setEmail( "wang@163.com" );        employee.setGender( 2 );        employee.setDId( 2 );        boolean b = employeeService.save( employee );        if(b) {            return "sava success";        }else {            return "sava fail";        }    }}
    

源码

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