一、整合Mybatis

配置文件

pom.xml

application.yml

jdbc.properties

generatorConfig.xml

启动类

测试

二、整合Mybatis-plus

Mybatis-plus

新建项目

pom.xml

application.yml

在项目导入mybatis-plus的代码生成的类

完成基本增删改查方法开发

三、Mybatisplus中使用Mybatis实现多表连查的功能

一、整合Mybatis

确保项目启动成功

配置文件

pom.xml

修改mysql版本

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.44</version>
        </dependency>

            <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>

application.yml

mybatis:
    mapper-locations: classpath:mappers/**/*.xml
    type-aliases-package: com.maomao.pringbootmybatis.model
server:
    port: 8082
spring:
    application:
        name: spbootmybatis
    datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost:3306/mybatis_ssm?useUnicode=true&characterEncoding=UTF-8
        password: 123456
        username: root

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis_ssm?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-->
    <classPathEntry location="F:\Maven\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.maomao.spbootmybatis.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.maomao.spbootmybatis.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.maomao.spbootmybatis.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">-->
        <!--<!– 忽略列，不生成bean 字段 –>-->
        <!--<!– <ignoreColumn column="FRED" /> –>-->
        <!--<!– 指定列的java数据类型 –>-->
        <!--<!– <columnOverride column="LONG_VARCHAR_FIELD" jdbcType="VARCHAR" /> –>-->
        <!--</table>-->

        <table schema="" tableName="t_mvc_book" domainObjectName="Book"
               enableCountByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" enableUpdateByExample="false">
        </table>

    </context>
</generatorConfiguration>

启动类

package com.maomao.spbootmybatis;

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.maomao.spbootmybatis.mapper")
//开启对事物的管理
@EnableTransactionManagement
@SpringBootApplication
public class SpbootmybatisApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpbootmybatisApplication.class, args);
    }

}

测试

利用Eolink进行测试

二、整合Mybatis-plus

Mybatis-plus

官网

MyBatis-Plus

①企业中大量使用

②减少*Mapper.xml中的SQL编写

③与若依相比，略为繁琐，但是可移植性极强

新建项目

勾选五个组件：

lombok、web、jdbc、mybatis-plus、MySQL driver

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.maomao</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mybatis plus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>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-core</artifactId>
            <version>3.4.2</version>
            <scope>compile</scope>
        </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.maomao.springbootmp.SpringbootmpApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

application.yml

server:
    port: 8082
spring:
    application:
        name: springbootmp
    datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost:3306/mybatis_ssm?useUnicode=true&characterEncoding=UTF-8
        password: 123456
        username: root
logging:
    level:
        com.maomao.springbootmp: debug
mybatis-plus:
    mapper-locations: classpath:mappers/**/*.xml
    type-aliases-package: com.maomao.springbootmp.book.model

在项目导入mybatis-plus的代码生成的类

copy官网

注意事项：

（1）需要更改代码生成的module名

（2）需要设置父包的位置

（3）要预先创建好mappers的文件夹

MPGenerator.java

package com.maomao.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，就是Springboot01
        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BaseResultMap
        gc.setActiveRecord(false);// 不需要ActiveRecord特性的请改为false
        gc.setEnableCache(false);// XML 二级缓存
        gc.setBaseResultMap(true);// XML ResultMap
        gc.setBaseColumnList(true);// XML columList
        //gc.setSwagger2(true); //实体属性 Swagger2 注解
        gc.setAuthor("maomao");

        // 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/mybatis_ssm?useUnicode=true&characterEncoding=UTF-8");
        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);
        }
//        设置父包
        pc.setParent("com.maomao.springbootmp")
                .setMapper("mapper")
                .setService("service")
                .setController("controller")
                .setEntity("model");
        mpg.setPackageInfo(pc);

        // 4.自定义配置
        InjectionConfig cfg = new InjectionConfig() {
            @Override
            public void initMap() {
                // to do nothing
            }
        };

        // 如果模板引擎是 freemarker
        String 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) {
            @Override
            public 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plus
        strategy.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_user
        strategy.setTablePrefix("t_", "t_sys_");
        //strategy.setTablePrefix(scanner("请输入表前缀"));
        mpg.setStrategy(strategy);
        mpg.setTemplateEngine(new FreemarkerTemplateEngine());
        // 执行
        mpg.execute();
    }
}

运行：

mybatis-plus接口的讲解

（1）basemapper/baseservice都已经封装好了基本的增删改查及基本使用

（2）QueryWrapper的使用，可以构建查询条件，减少配置文件xml的sql编写

完成基本增删改查方法开发

MvcBookController.java

package com.maomao.springbootmp.book.controller;


import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.maomao.springbootmp.book.model.MvcBook;
import com.maomao.springbootmp.book.service.MvcBookService;
import org.springframework.beans.factory.annotation.Autowired;
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;

import java.util.List;

/**
 * <p>
 *  前端控制器
 * </p>
 *
 * @author maomao
 * @since 2022-12-02
 */
@RestController
@RequestMapping("/mp")
public class MvcBookController {
    @Autowired
    private 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){
//        如果使用的是Mybatis，那么我们需要写SQL语句，而MP不需要
        QueryWrapper qw=new QueryWrapper();
        qw.like("bname",book.getBname());
        return bookService.list();
    }


    //    查询单个
    @GetMapping("/get")
    public MvcBook get(MvcBook book){
        return bookService.getById(book.getBid());
    }

    //    增加
    @PutMapping("/add")
    public boolean add(MvcBook book){
        return bookService.save(book);
    }

    //    删除
    @PutMapping("/delete")
    public boolean delete(MvcBook book){
        return bookService.removeById(book.getBid());
    }

    //    修改
    @PutMapping("/update")
    public boolean update(MvcBook book){
        return bookService.saveOrUpdate(book);
    }

}

测试

三、Mybatisplus中使用Mybatis实现多表连查的功能

用户、角色、用户角色中间表连表查询的案例

MvcBookMappper.xml

<?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.maomao.springbootmp.book.mapper.MvcBookMapper">

    <!-- 通用查询映射结果 -->
    <resultMap id="BaseResultMap" type="com.maomao.springbootmp.book.model.MvcBook">
        <id column="bid" property="bid" />
        <result column="bname" property="bname" />
        <result column="price" property="price" />
    </resultMap>

    <!-- 通用查询结果列 -->
    <sql id="Base_Column_List">
        bid, bname, price
    </sql>

    <!--注意mybatisplus中的配置文件默认也是没有生成对应增删改查的SQL语句的，因为mp是顶层接口都封装好了，调用即可-->
    <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 r
        where u.userid = ur.userid and ur.roleid = r.roleid
        <if test="username != null and username != ''">
            and u.username = #{username}
        </if>
    </select>
</mapper>

MvcBookMapper.java

package com.maomao.springbootmp.book.mapper;

import com.maomao.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 maomao
 * @since 2022-12-02
 */
@Repository
public interface MvcBookMapper extends BaseMapper<MvcBook> {

    List<Map> queryUserRole(Map map);
}

MvcBookService.java

package com.maomao.springbootmp.book.service;

import com.maomao.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 maomao
 * @since 2022-12-02
 */
public interface MvcBookService extends IService<MvcBook> {

    List<Map> queryUserRole(Map map);

}

MvcBookServiceImpl.java

package com.maomao.springbootmp.book.service.impl;

import com.maomao.springbootmp.book.model.MvcBook;
import com.maomao.springbootmp.book.mapper.MvcBookMapper;
import com.maomao.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 maomao
 * @since 2022-12-02
 */
@Service
public class MvcBookServiceImpl extends ServiceImpl<MvcBookMapper, MvcBook> implements MvcBookService {

    @Autowired
    private MvcBookMapper bookMapper;
    @Override
    public List<Map> queryUserRole(Map map) {
        return bookMapper.queryUserRole(map);
    }
}

MvcBookController.java

 //多表联查 ，用户姓名对应角色的功能，论证mybatis是一样可以使用mybatis功能
    @GetMapping("/queryUserRole")
    public List<Map> queryUserRole(String uname){
// 前端传了一个zs
        Map map = new HashMap();
        map.put("username",uname);
        return bookService.queryUserRole(map);
    }

用Eolink进行测试