SpringBoot:ssm和springboot整合

一、整合Mybatis

因为要使用逆向生成代码

pom.xml

generatorConfig.xml

application.yml

测试

BookController

SpringbootmybatisApplication

jdbc.properties

二、整合mybatisplus

简介

application.yml

MPGenerator

SpringbootmpApplication

三、使用mybatisplus完成多表联查功能

MvcBookMapper.xml

MvcBookService

MvcBookServiceImpl

MvcBookMapper

MvcBookController

一、整合Mybatis

新建一个springboot的模块在勾选组件时

创建模块成功之后

降低MySQL的版本

账户密码

application.yml

mybatis:mapper-locations: classpath:mappers/*xmltype-aliases-package: com.cdl.springbootmybatis.mybatis.entity
server:port: 8080
spring:application:name: springbootmybatisdatasource:driver-class-name: com.mysql.jdbc.Drivername: defaultDataSourcepassword: 123456url: jdbc:mysql://localhost:3306/mysql?useUnicode=true&characterEncoding=UTF-8username: root

因为要使用逆向生成代码

pom.xml

<plugin><groupId>org.mybatis.generator</groupId><artifactId>mybatis-generator-maven-plugin</artifactId><version>1.3.2</version><dependencies><!--使用Mybatis-generator插件不能使用太高版本的mysql驱动 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.44</version></dependency></dependencies><configuration><overwrite>true</overwrite></configuration></plugin>

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mysql?useUnicode=true&characterEncoding=UTF-8
jdbc.username=root
jdbc.password=123456

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><!-- 引入配置文件 --><properties resource="jdbc.properties"/><!--指定数据库jdbc驱动jar包的位置--><classPathEntrylocation="E:\\cdl_mvn_repository\\mysql\\mysql-connector-java\\5.1.44\\mysql-connector-java-5.1.44.jar"/><!-- 一个数据库一个context --><context id="infoGuardian"><!-- 注释 --><commentGenerator><property name="suppressAllComments" value="true"/><!-- 是否取消注释 --><property name="suppressDate" value="true"/> <!-- 是否生成注释代时间戳 --></commentGenerator><!-- jdbc连接 --><jdbcConnection driverClass="${jdbc.driver}"connectionURL="${jdbc.url}" userId="${jdbc.username}" password="${jdbc.password}"/><!-- 类型转换 --><javaTypeResolver><!-- 是否使用bigDecimal， false可自动转化以下类型（Long, Integer, Short, etc.） --><property name="forceBigDecimals" value="false"/></javaTypeResolver><!-- 01 指定javaBean生成的位置 --><!-- targetPackage：指定生成的model生成所在的包名 --><!-- targetProject：指定在该项目下所在的路径  --><javaModelGenerator targetPackage="com.cdl.springbootmybatis.model"targetProject="src/main/java"><!-- 是否允许子包，即targetPackage.schemaName.tableName --><property name="enableSubPackages" value="false"/><!-- 是否对model添加构造函数 --><property name="constructorBased" value="true"/><!-- 是否针对string类型的字段在set的时候进行trim调用 --><property name="trimStrings" value="false"/><!-- 建立的Model对象是否 不可改变  即生成的Model对象不会有 setter方法，只有构造方法 --><property name="immutable" value="false"/></javaModelGenerator><!-- 02 指定sql映射文件生成的位置 --><sqlMapGenerator targetPackage="com.cdl.springbootmybatis.mapper"targetProject="src/main/resources/mappers"><!-- 是否允许子包，即targetPackage.schemaName.tableName --><property name="enableSubPackages" value="false"/></sqlMapGenerator><!-- 03 生成XxxMapper接口 --><!-- type="ANNOTATEDMAPPER",生成Java Model 和基于注解的Mapper对象 --><!-- type="MIXEDMAPPER",生成基于注解的Java Model 和相应的Mapper对象 --><!-- type="XMLMAPPER",生成SQLMap XML文件和独立的Mapper接口 --><javaClientGenerator targetPackage="com.cdl.springbootmybatis.mapper"targetProject="src/main/java" type="XMLMAPPER"><!-- 是否在当前路径下新加一层schema,false路径com.oop.eksp.user.model， true:com.oop.eksp.user.model.[schemaName] --><property name="enableSubPackages" value="false"/></javaClientGenerator><!-- 配置表信息 --><!-- schema即为数据库名 --><!-- tableName为对应的数据库表 --><!-- domainObjectName是要生成的实体类 --><!-- enable*ByExample是否生成 example类 --><!--<table schema="" tableName="t_book" domainObjectName="Book"--><!--enableCountByExample="false" enableDeleteByExample="false"--><!--enableSelectByExample="false" enableUpdateByExample="false">--><!--&lt;!&ndash; 忽略列，不生成bean 字段 &ndash;&gt;--><!--&lt;!&ndash; <ignoreColumn column="FRED" /> &ndash;&gt;--><!--&lt;!&ndash; 指定列的java数据类型 &ndash;&gt;--><!--&lt;!&ndash; <columnOverride column="LONG_VARCHAR_FIELD" jdbcType="VARCHAR" /> &ndash;&gt;--><!--</table>--><table schema="" tableName="t_mvc_book" domainObjectName="Book"enableCountByExample="false" enableDeleteByExample="false"enableSelectByExample="false" enableUpdateByExample="false"></table></context>
</generatorConfiguration>

application.yml

mybatis:mapper-locations: classpath:mappers/**/*.xmltype-aliases-package: com.cdl.springbootmybatis.mybatis.entity
server:port: 8080
spring:application:name: springbootmybatisdatasource:driver-class-name: com.mysql.jdbc.Drivername: defaultDataSourcepassword: 123456url: jdbc:mysql://localhost:3306/mysql?useUnicode=true&characterEncoding=UTF-8username: root

因为是一个新的工作区间（从没有运行过maven的）一定要配置maven逆向生成的命令

完成该配置之后再去运行逆向生成

运行成功

让生成出来的mapper.xml

com.cdl.springbootmybatis.model.Book中的com.cdl.springbootmybatis.model

<?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="com.cdl.springbootmybatis.mapper.BookMapper" ><resultMap id="BaseResultMap" type="com.cdl.springbootmybatis.model.Book" ><constructor ><idArg column="bid" jdbcType="INTEGER" javaType="java.lang.Integer" /><arg column="bname" jdbcType="VARCHAR" javaType="java.lang.String" /><arg column="price" jdbcType="REAL" javaType="java.lang.Float" /></constructor></resultMap><sql id="Base_Column_List" >bid, bname, price</sql><select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >select <include refid="Base_Column_List" />from t_mvc_bookwhere bid = #{bid,jdbcType=INTEGER}</select><delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >delete from t_mvc_bookwhere bid = #{bid,jdbcType=INTEGER}</delete><insert id="insert" parameterType="com.cdl.springbootmybatis.model.Book" >insert into t_mvc_book (bid, bname, price)values (#{bid,jdbcType=INTEGER}, #{bname,jdbcType=VARCHAR}, #{price,jdbcType=REAL})</insert><insert id="insertSelective" parameterType="com.cdl.springbootmybatis.model.Book" >insert into t_mvc_book<trim prefix="(" suffix=")" suffixOverrides="," ><if test="bid != null" >bid,</if><if test="bname != null" >bname,</if><if test="price != null" >price,</if></trim><trim prefix="values (" suffix=")" suffixOverrides="," ><if test="bid != null" >#{bid,jdbcType=INTEGER},</if><if test="bname != null" >#{bname,jdbcType=VARCHAR},</if><if test="price != null" >#{price,jdbcType=REAL},</if></trim></insert><update id="updateByPrimaryKeySelective" parameterType="com.cdl.springbootmybatis.model.Book" >update t_mvc_book<set ><if test="bname != null" >bname = #{bname,jdbcType=VARCHAR},</if><if test="price != null" >price = #{price,jdbcType=REAL},</if></set>where bid = #{bid,jdbcType=INTEGER}</update><update id="updateByPrimaryKey" parameterType="com.cdl.springbootmybatis.model.Book" >update t_mvc_bookset bname = #{bname,jdbcType=VARCHAR},price = #{price,jdbcType=REAL}where bid = #{bid,jdbcType=INTEGER}</update>
</mapper>

和 application.yml 对应

application.yml

mybatis:mapper-locations: classpath:mappers/**/*.xmltype-aliases-package: com.cdl.springbootmybatis.model
server:port: 8080
spring:application:name: springbootmybatisdatasource:driver-class-name: com.mysql.jdbc.Drivername: defaultDataSourcepassword: 123456url: jdbc:mysql://localhost:3306/mysql?useUnicode=true&characterEncoding=UTF-8username: root

此时mapper.xml中的com.cdl.springbootmybatis.model.Book可以改为Book

测试

写一个controller

BookController

package com.cdl.springbootmybatis.web;import com.cdl.springbootmybatis.mapper.BookMapper;
import com.cdl.springbootmybatis.model.Book;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;/*** @author cdl* @site www.cdl.com* @create 2022-10-31 20:00*/
@RestController
@RequestMapping("/mybatis")
public class BookController {@Autowiredpublic BookMapper bookMapper;//查询@GetMapping("/get")public Book list(Integer bid){return bookMapper.selectByPrimaryKey(bid);}//删除@DeleteMapping("/delete")public int delete(Integer bid){return bookMapper.deleteByPrimaryKey(bid);}//新增@PutMapping("/add")public int add(Book book){return bookMapper.insertSelective(book);}}

注意：

开启包扫描和事务管理（在启动类加）

SpringbootmybatisApplication

package com.cdl.springbootmybatis;import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.transaction.annotation.EnableTransactionManagement;//完成对mapper接口的扫描
@MapperScan("com.cdl.springbootmybatis.mapper")
//开启事务管理
@EnableTransactionManagement
@SpringBootApplication
public class SpringbootmybatisApplication {public static void main(String[] args) {SpringApplication.run(SpringbootmybatisApplication.class, args);}}

测试时拿不到数据 404 控制台

解决方法：在配置文件中的连接数据库的URL后面添加 useSSL=false

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mysql?useUnicode=true&characterEncoding=UTF-8&useSSL=false
jdbc.username=root
jdbc.password=123456

效果：

控制台

查询

删除

删除成功

新增

新增成功

整合mybatis成功

二、整合mybatisplus

简介

MyBatis-Plus

MyBatis-Plus (opens new window)（简称 MP）是一个 MyBatis (opens new window)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。

创建一个新模块勾选以下组件

导入新的pom依赖（用于mp的代码生成）
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-generator</artifactId>
<version>3.4.1</version>
</dependency>
<dependency>
<groupId>org.freemarker</groupId>
<artifactId>freemarker</artifactId>
<version>2.3.31</version>
</dependency>

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 https://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.cdl</groupId><artifactId>springbootmp</artifactId><version>0.0.1-SNAPSHOT</version><name>springbootmp</name><description>Demo project for Spring Boot</description><properties><java.version>1.8</java.version><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><spring-boot.version>2.3.7.RELEASE</spring-boot.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.4.2</version></dependency><!--添加额外的pom依赖:用于mp的代码生成--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-generator</artifactId><version>3.4.1</version></dependency><dependency><groupId>org.freemarker</groupId><artifactId>freemarker</artifactId><version>2.3.31</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.44</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope><exclusions><exclusion><groupId>org.junit.vintage</groupId><artifactId>junit-vintage-engine</artifactId></exclusion></exclusions></dependency></dependencies><dependencyManagement><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-dependencies</artifactId><version>${spring-boot.version}</version><type>pom</type><scope>import</scope></dependency></dependencies></dependencyManagement><build><plugins><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><version>3.8.1</version><configuration><source>1.8</source><target>1.8</target><encoding>UTF-8</encoding></configuration></plugin><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId><version>2.3.7.RELEASE</version><configuration><mainClass>com.cdl.springbootmp.SpringbootmpApplication</mainClass></configuration><executions><execution><id>repackage</id><goals><goal>repackage</goal></goals></execution></executions></plugin></plugins></build></project>

修改配置

application.yml

server:port: 8080
spring:application:name: springbootmpdatasource:driver-class-name: com.mysql.jdbc.Drivername: defaultDataSourcepassword: 123456url: jdbc:mysql://localhost:3306/mysql?useUnicode=true&characterEncoding=UTF-8username: root
mybatis-plus:mapper-locations: classpath:mappers/**/*.xmltype-aliases-package: com.cdl.springbootmp.book.model

新建一个mp的包放入代码生成的类（在官网的代码生成中修改得出来的）

MPGenerator

package com.cdl.springbootmp.mp;import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.core.exceptions.MybatisPlusException;
import com.baomidou.mybatisplus.core.toolkit.StringPool;
import com.baomidou.mybatisplus.core.toolkit.StringUtils;
import com.baomidou.mybatisplus.generator.AutoGenerator;
import com.baomidou.mybatisplus.generator.InjectionConfig;
import com.baomidou.mybatisplus.generator.config.*;
import com.baomidou.mybatisplus.generator.config.po.TableInfo;
import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
import com.baomidou.mybatisplus.generator.engine.FreemarkerTemplateEngine;import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;/*** mybatis-plus代码生成*/
public class MPGenerator {/*** <p>* 读取控制台内容* </p>*/public static String scanner(String tip) {Scanner scanner = new Scanner(System.in);StringBuilder help = new StringBuilder();help.append("请输入" + tip);System.out.println(help.toString());if (scanner.hasNext()) {String ipt = scanner.next();if (StringUtils.isNotBlank(ipt)) {if ("quit".equals(ipt)) return "";return ipt;}}throw new MybatisPlusException("请输入正确的" + tip + "！");}public static void main(String[] args) {// 代码生成器AutoGenerator mpg = new AutoGenerator();// 1.全局配置GlobalConfig gc = new GlobalConfig();//System.getProperty("user.dir")指的是工作区间  "/springbootmp"所需要生成代码的模块String projectPath = System.getProperty("user.dir") + "/springbootmp";System.out.println(projectPath);gc.setOutputDir(projectPath + "/src/main/java");gc.setOpen(false);gc.setBaseResultMap(true);//生成BaseResultMapgc.setActiveRecord(false);// 不需要ActiveRecord特性的请改为falsegc.setEnableCache(false);// XML 二级缓存gc.setBaseResultMap(true);// XML ResultMapgc.setBaseColumnList(true);// XML columList//gc.setSwagger2(true); //实体属性 Swagger2 注解gc.setAuthor("cdl");// 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");gc.setIdType(IdType.AUTO);mpg.setGlobalConfig(gc);// 2.数据源配置DataSourceConfig dsc = new DataSourceConfig();dsc.setDbType(DbType.MYSQL);dsc.setUrl("jdbc:mysql://localhost:3306/mysql?useUnicode=true&characterEncoding=UTF-8&useSSL=false");dsc.setDriverName("com.mysql.jdbc.Driver");dsc.setUsername("root");dsc.setPassword("123456");mpg.setDataSource(dsc);// 3.包配置PackageConfig pc = new PackageConfig();String moduleName = scanner("模块名(quit退出，表示没有模块名)");if (StringUtils.isNotBlank(moduleName)) {pc.setModuleName(moduleName);}//设置基包(父包)pc.setParent("com.cdl.springbootmp").setMapper("mapper").setService("service").setController("controller").setEntity("model");mpg.setPackageInfo(pc);// 4.自定义配置InjectionConfig cfg = new InjectionConfig() {@Overridepublic void initMap() {// to do nothing}};// 如果模板引擎是 freemarkerString templatePath = "/templates/mapper.xml.ftl";// 自定义输出配置List<FileOutConfig> focList = new ArrayList<>();// 自定义配置会被优先输出focList.add(new FileOutConfig(templatePath) {@Overridepublic String outputFile(TableInfo tableInfo) {// 自定义输出文件名 ， 如果你 Entity 设置了前后缀、此处注意 xml 的名称会跟着发生变化！！if (StringUtils.isNotBlank(pc.getModuleName())) {return projectPath + "/src/main/resources/mappers/" + pc.getModuleName() + "/" + tableInfo.getEntityName() + "Mapper" + StringPool.DOT_XML;} else {return projectPath + "/src/main/resources/mappers/" + tableInfo.getEntityName() + "Mapper" + StringPool.DOT_XML;}}});cfg.setFileOutConfigList(focList);mpg.setCfg(cfg);// 配置模板TemplateConfig templateConfig = new TemplateConfig();templateConfig.setXml(null);mpg.setTemplate(templateConfig);// 5.策略配置StrategyConfig strategy = new StrategyConfig();// 表名生成策略(下划线转驼峰命名)strategy.setNaming(NamingStrategy.underline_to_camel);// 列名生成策略(下划线转驼峰命名)strategy.setColumnNaming(NamingStrategy.underline_to_camel);// 是否启动Lombok配置strategy.setEntityLombokModel(true);// 是否启动REST风格配置strategy.setRestControllerStyle(true);// 自定义实体父类strategy.setSuperEntityClass("com.baomidou.mybatisplus.extension.activerecord.Model");// 自定义service父接口strategy.setSuperServiceClass("com.baomidou.mybatisplus.extension.service.IService");// 自定义service实现类strategy.setSuperServiceImplClass("com.baomidou.mybatisplus.extension.service.impl.ServiceImpl");// 自定义mapper接口strategy.setSuperMapperClass("com.baomidou.mybatisplus.core.mapper.BaseMapper");strategy.setSuperEntityColumns("id");// 写于父类中的公共字段plusstrategy.setSuperEntityColumns("id");strategy.setInclude(scanner("表名，多个英文逗号分割").split(","));strategy.setControllerMappingHyphenStyle(true);//表名前缀(可变参数)：“t_”或”“t_模块名”，例如：t_user或t_sys_userstrategy.setTablePrefix("t_", "t_sys_");//strategy.setTablePrefix(scanner("请输入表前缀"));mpg.setStrategy(strategy);mpg.setTemplateEngine(new FreemarkerTemplateEngine());// 执行mpg.execute();}
}

注意：记得新建一个mappers的文件夹在resources下

运行该main方法

成功了

实现基本的增删改查 MvcBookController

package com.cdl.springbootmp.book.controller;import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.cdl.springbootmp.book.model.MvcBook;
import com.cdl.springbootmp.book.service.MvcBookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import java.util.List;/*** <p>*  前端控制器* </p>** @author cdl* @since 2022-10-31*/
@RestController
@RequestMapping("/book/mvc-book")
public class MvcBookController {@Autowiredprivate MvcBookService bookService;//    查询所有@GetMapping("/list")public List<MvcBook> list(){return bookService.list();}//    按条件查询@GetMapping("/ListByCondition")public List<MvcBook> ListByCondition(MvcBook book){//如果使用的市mybatis 那么需要写SQL语句QueryWrapper w = new QueryWrapper();w.like("bname",book.getBname());return bookService.list(w);}//    查询单个@GetMapping("/load")public MvcBook load(MvcBook book){//QueryWrapper w = new QueryWrapper();//w.like("bid",book.getBid());//return bookService.getOne(w);return bookService.getById(book.getBid());}//    增加@PutMapping("/add")public boolean add(MvcBook book){boolean save = bookService.save(book);return save;}//    修改@PostMapping("/update")public boolean update(MvcBook book){boolean save = bookService.saveOrUpdate(book);return save;}//    删除@DeleteMapping("/delete")public boolean delete(MvcBook book){boolean save = bookService.removeById(book.getBid());return save;}}

注意：

SpringbootmpApplication

package com.cdl.springbootmp;import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.transaction.annotation.EnableTransactionManagement;@MapperScan("com.cdl.springbootmp.book.mapper")  //扫描接口
@EnableTransactionManagement  //开启事务
@SpringBootApplication
public class SpringbootmpApplication {public static void main(String[] args) {SpringApplication.run(SpringbootmpApplication.class, args);}}

测试：

查询

查询带条件

修改

修改成功

三、使用mybatisplus完成多表联查功能

MvcBookMapper.xml

 <!--多表联查--><select id="queryUserRole" parameterType="java.util.Map" resultType="java.util.Map">SELECT u.username,r.rolename FROM t_shiro_user u,t_shiro_user_role ur,t_shiro_role rwhere u.userid = ur.userid and ur.roleid = r.roleid<if test="username != null and username != ''">and u.username = #{username}</if></select>

MvcBookService

package com.cdl.springbootmp.book.service;import com.cdl.springbootmp.book.model.MvcBook;
import com.baomidou.mybatisplus.extension.service.IService;import java.util.List;
import java.util.Map;/*** <p>*  服务类* </p>** @author cdl* @since 2022-10-31*/
public interface MvcBookService extends IService<MvcBook> {//多表联查List<Map> queryUserRole(Map map);}

MvcBookServiceImpl

package com.cdl.springbootmp.book.service.impl;import com.cdl.springbootmp.book.model.MvcBook;
import com.cdl.springbootmp.book.mapper.MvcBookMapper;
import com.cdl.springbootmp.book.service.MvcBookService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;
import java.util.Map;/*** <p>*  服务实现类* </p>** @author cdl* @since 2022-10-31*/
@Service
public class MvcBookServiceImpl extends ServiceImpl<MvcBookMapper, MvcBook> implements MvcBookService {@Autowiredprivate MvcBookMapper bookMapper;public List<Map> queryUserRole(Map map){return bookMapper.queryUserRole(map);}}

MvcBookMapper

package com.cdl.springbootmp.book.mapper;import com.cdl.springbootmp.book.model.MvcBook;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.springframework.stereotype.Repository;import java.util.List;
import java.util.Map;/*** <p>*  Mapper 接口* </p>** @author cdl* @since 2022-10-31*/
@Repository
public interface MvcBookMapper extends BaseMapper<MvcBook> {//多表联查List<Map> queryUserRole(Map map);}

MvcBookController

中加这个方法

 //多表联查 用户账户对应角色的功能  论证mybatisplus一样可以使用mybatis@GetMapping("/userRole")public List<Map> userRole(String uname){Map map = new HashMap();map.put("username",uname);List<Map> maps = bookService.queryUserRole(map);return maps;}

测试：