• Spring boot集成Mybatis-Plus,通用Mapper


          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。(摘自mybatis-plus官网)Mybatis虽然已经给我们提供了很大的方便,但它还是有不足之处,MP的存在就是为了稍稍弥补Mybatis的不足。在我们使用Mybatis时会发现,每当要写一个业务逻辑的时候都要在DAO层写一个方法,再对应一个SQL,即使是简单的条件查询、即使仅仅改变了一个条件都要在DAO层新增一个方法,针对这个问题,MP这样一个框架,一种集Mybatis与Hibernate的优点一起的框架。它提供了Hibernate的单表CURD操作的方便同时,又保留了Mybatis的特性。

    创建项目,

    引入依赖:

    <?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.chaoqi</groupId>
        <artifactId>springboot_mybatisplus</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <packaging>jar</packaging>
    
        <name>springboot_mybatisplus</name>
        <description>Demo project for Spring Boot</description>
    
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.0.0.RELEASE</version>
            <relativePath/>
        </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-jdbc</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.2</version>
            </dependency>
    
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <!--添加jsp依赖 -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-tomcat</artifactId>
            </dependency>
            <dependency>
                <groupId>org.apache.tomcat.embed</groupId>
                <artifactId>tomcat-embed-jasper</artifactId>
            </dependency>
            <!-- SpringBoot - MyBatis 逆向工程 -->
            <dependency>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-core</artifactId>
                <version>1.3.2</version>
            </dependency>
    
            <!-- MyBatis 通用 Mapper -->
            <dependency>
                <groupId>tk.mybatis</groupId>
                <artifactId>mapper-spring-boot-starter</artifactId>
                <version>1.1.4</version>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
                <plugin>
                    <groupId>org.mybatis.generator</groupId>
                    <artifactId>mybatis-generator-maven-plugin</artifactId>
                    <version>1.3.2</version>
                    <configuration>
                        <configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
                        <verbose>true</verbose>
                        <overwrite>true</overwrite>
                    </configuration>
                    <executions>
                        <execution>
                            <id>Generate MyBatis Artifacts</id>
                            <goals>
                                <goal>generate</goal>
                            </goals>
                        </execution>
                    </executions>
                    <dependencies>
                        <dependency>
                            <groupId>org.mybatis.generator</groupId>
                            <artifactId>mybatis-generator-core</artifactId>
                            <version>1.3.2</version>
                        </dependency>
                        <dependency>
                            <groupId>tk.mybatis</groupId>
                            <artifactId>mapper</artifactId>
                            <version>3.5.0</version>
                        </dependency>
                    </dependencies>
                </plugin>
    
            </plugins>
        </build>
    
    </project>

    配置配置文件:

    server:
      port: 8080
    
    spring:
      mvc:
        view:
          prefix: /WEB-INF/jsp/
          suffix: .jsp
      datasource:
        url: jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8&useUnicode=true&useSSL=false
        username: root
        password: root
        driver-class-name: com.mysql.jdbc.Driver
    
    mybatis:
      mapper-locations: classpath:mapper/*.xml
      type-aliases-package: com.chaoqi.springboot_mybatisplus.domain

    逆向生成文件:

     创建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>
    
        <properties resource="application.yml"/>
        <classPathEntry location="C:/Users/Administrator/.m2/repository/mysql/mysql-connector-java/5.1.6/mysql-connector-java-5.1.6.jar"/>
        <context id="Mysql" targetRuntime="MyBatis3Simple" defaultModelType="flat">
            <property name="beginningDelimiter" value="`"/>
            <property name="endingDelimiter" value="`"/>
            <property name="javaFileEncoding" value="UTF-8"/>
            <plugin type="tk.mybatis.mapper.generator.MapperPlugin">
                <property name="mappers" value="tk.mybatis.mapper.common.Mapper"/>
            </plugin>
            <!-- 注释 -->
            <commentGenerator>
                <!-- 是否生成注释代时间戳 -->
                <property name="suppressDate" value="true"/>
                <!-- 是否去除自动生成的注释 true:是 : false:否 -->
                <property name="suppressAllComments" value="false"/>
            </commentGenerator>
            <!-- JDBC连接 -->
            <jdbcConnection
                    driverClass="com.mysql.jdbc.Driver"
                    connectionURL="jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8"
                    userId="root"
                    password="root">
            </jdbcConnection>
            <!-- 生成实体类地址 -->
            <javaModelGenerator targetPackage="com.mybatisplus.mybatisplustest.dao.domain" targetProject="src/main/java"/>
            <!-- 生成mapper xml文件 -->
            <sqlMapGenerator targetPackage="mapper" targetProject="src/main/resources"/>
            <!-- 生成mapper xml对应Client-->
            <javaClientGenerator targetPackage="com.mybatisplus.mybatisplustest.dao.mapper" targetProject="src/main/java"
                                 type="XMLMAPPER"/>
            <!-- 配置表信息 -->
            <table tableName="%">
                <!--mysql 配置-->
                <generatedKey column="id" sqlStatement="Mysql"/>
                <!--oracle 配置-->
                <!--<generatedKey column="id" sqlStatement="select SEQ_{1}.nextval from dual" identity="false" type="pre"/>-->
            </table>
        </context>
    </generatorConfiguration>

    需要修改其中的<classPathEntry>中的路径,<jdbcConnection>中的数据库配置,以及下面三个生成路径

    然后找到该文件并运行,根据表生成文件

    如果这里报错,根据报错信息查看是否配置文件有错误

    生成的结构:

    接下来整合MybatisPlus:

    创建Service和Controller,不需要手写SQL语句

    public interface UserInfoService {
    
        public List<UserInfo> getMusicInfo();
    }
    @Service
    public class UserInfoServiceImpl implements UserInfoService {
    
    
        @Autowired
        private UserInfoMapper userInfoMapper;
    
        @Override
        public List<UserInfo> getMusicInfo() {
            List<UserInfo> userInfos = userInfoMapper.selectAll();
            return userInfos;
        }
    }
    @RestController
    public class UserinfoController {
    
        @Autowired
        private UserInfoService userInfoService;
    
        @RequestMapping("/alluser")
        public List<UserInfo> getUserInfo() {
            List<UserInfo> musicInfo1 = userInfoService.getMusicInfo();
            return musicInfo1;
        }
    
    }

    在启动类上配置mapper

    @SpringBootApplication
    @MapperScan("com.mybatisplus.mybatisplustest.dao.mapper")
    public class MybatisplustestApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(MybatisplustestApplication.class, args);
        }
    }

    然后启动测试

    注意:

    //    Caused by: tk.mybatis.mapper.MapperException: id - 该字段@GeneratedValue配置只允许以下几种形式:
    //            1.全部数据库通用的@GeneratedValue(generator="UUID")
    //            2.useGeneratedKeys的@GeneratedValue(generator="JDBC")
    //            3.类似mysql数据库的@GeneratedValue(strategy=GenerationType.IDENTITY[,generator="Mysql"])
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  • 原文地址:https://www.cnblogs.com/jiangwz/p/9393040.html
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