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http://mp.baomidou.com/，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
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.gf</groupId>
<artifactId>springboot-mybatis</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>springboot-mybatis</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.0.1</version>
</dependency>
<dependency>
<groupId>org.apache.velocity</groupId>
<artifactId>velocity</artifactId>
<version>1.7</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
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
<?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="${package.Mapper}.${table.mapperName}">
#if(${enableCache})
<!-- 开启二级缓存 -->
<cache type="org.mybatis.caches.ehcache.LoggingEhcache"/>
#end
#if(${baseResultMap})
<!-- 通用查询映射结果 -->
<resultMap id="BaseResultMap" type="${package.Entity}.${entity}">
#foreach($field in ${table.fields})
#if(${field.keyFlag})##生成主键排在第一位
<id column="${field.name}" property="${field.propertyName}" />
#end
#end
#foreach($field in ${table.commonFields})##生成公共字段
<result column="${field.name}" property="${field.propertyName}" />
#end
#foreach($field in ${table.fields})
#if(!${field.keyFlag})##生成普通字段
<result column="${field.name}" property="${field.propertyName}" />
#end
#end
</resultMap>
#end
#if(${baseColumnList})
<!-- 通用查询结果列 -->
<sql id="Base_Column_List">
#foreach($field in ${table.commonFields})
${field.name},
#end
${table.fieldNames}
</sql>
#end
</mapper>
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<FileOutConfig> 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/test
spring.datasource.username=xxxxxx
spring.datasource.password=xxxxxx
spring.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<Employee> 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";
}
}
}
源码下载：https://github.com/gf-huanchupk/SpringBootLearning