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一、在spring boot中配置mybatis-plus

• 1、创建一个spring boot项目，注意勾选mysql

• 2、在pom.xml文件中添加mybatis-plus的依赖包

  <?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><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>3.1.3</version><relativePath/> </parent><groupId>com.example</groupId><artifactId>spring_mybatis</artifactId><version>0.0.1-SNAPSHOT</version><name>spring_mybatis</name><description>spring_mybatis</description><properties><java.version>17</java.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-devtools</artifactId><scope>runtime</scope><optional>true</optional></dependency><dependency><groupId>com.mysql</groupId><artifactId>mysql-connector-j</artifactId><scope>runtime</scope></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></dependency><!--    mybatis-plus依赖包    --><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.5.3.2</version></dependency><!-- 处理json的 --><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>2.0.40</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-starter</artifactId><version>1.2.19</version></dependency><dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.8.21</version></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId><configuration><excludes><exclude><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></exclude></excludes></configuration></plugin></plugins></build></project>

• 3、创建一个beego的数据库,并且创建一个user的表

  -- ------------------------
  -- 用户表
  -- ------------------------
  DROP TABLE IF EXISTS `user`;
  CREATE TABLE `user` (`id` int(11) NOT NULL PRIMARY KEY AUTO_INCREMENT  COMMENT '主键id',`username` varchar(50) not null  COMMENT '用户名',`password` varchar(100) not null COMMENT '密码',`status` tinyint(4) DEFAULT '1' COMMENT '状态,0表示禁止,1表示正常',`created_at` timestamp(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6) COMMENT '创建时间',`updated_at` timestamp(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6) ON UPDATE CURRENT_TIMESTAMP(6) COMMENT '更新时间',`deleted_at` timestamp(6) NULL DEFAULT NULL COMMENT '软删除时间'
  ) ENGINE=InnoDB  DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin COMMENT = "用户表";
  

• 4、在application.yml中配置mysql连接池及mybatis-plus的配置

  server:port: 9000spring:# 数据库配置datasource:url: jdbc:mysql://localhost:3306/beego?useUnicode=true&characterEncoding=utf8&allowMultiQueries=true&useSSL=false&useAffectedRows=true&serverTimezone=Asia/Shanghaidriver-class-name: com.mysql.cj.jdbc.Driverusername: rootpassword: 123456type: com.alibaba.druid.pool.DruidDataSource#配置mybatis-plus信息
  mybatis-plus:configuration:# 开启下划线转驼峰map-underscore-to-camel-case: trueauto-mapping-behavior: fulllog-impl: org.apache.ibatis.logging.stdout.StdOutImpl# mapping的路径mapper-locations: classpath*:mapper/**/*Mapper.xmlglobal-config:db-config:#主键类型  AUTO:"数据库ID自增", INPUT:"用户输入ID", ID_WORKER:"全局唯一ID (数字类型唯一ID)", UUID:"全局唯一ID UUID";id-type: AUTO# 逻辑删除(软删除)logic-delete-value: NOW()logic-not-delete-value: 'NULL'
  

• 5、在spring boot的入口文件配置要扫描的mapper路径

  package com.example.spring_mybatis;import lombok.extern.slf4j.Slf4j;
  import org.mybatis.spring.annotation.MapperScan;
  import org.springframework.boot.SpringApplication;
  import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication
  @MapperScan(basePackages = {"com.example.spring_mybatis.mapper"})
  @Slf4j
  public class SpringMybatisApplication {public static void main(String[] args) {SpringApplication.run(SpringMybatisApplication.class, args);log.info("服务已经启动localhost:9000");}
  }
  

• 6、简单运行项目,看看是否可以正常运行

二、对mybatis plus一些基本的配置

• 1、统一时间格式

  package com.example.spring_mybatis.config;import cn.hutool.core.date.DatePattern;
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
  import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
  import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
  import com.fasterxml.jackson.datatype.jsr310.deser.LocalTimeDeserializer;
  import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateSerializer;
  import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
  import com.fasterxml.jackson.datatype.jsr310.ser.LocalTimeSerializer;
  import lombok.extern.slf4j.Slf4j;
  import org.springframework.context.annotation.Bean;
  import org.springframework.context.annotation.Configuration;
  import org.springframework.stereotype.Component;import java.time.LocalDate;
  import java.time.LocalDateTime;
  import java.time.LocalTime;
  import java.time.format.DateTimeFormatter;@Component
  @Slf4j
  public class LocalDateTimeFormatConfig {@Beanpublic ObjectMapper objectMapper() {ObjectMapper objectMapper = new ObjectMapper();JavaTimeModule javaTimeModule = new JavaTimeModule();javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer(DateTimeFormatter.ofPattern(DatePattern.NORM_DATETIME_PATTERN)));javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer(DateTimeFormatter.ofPattern(DatePattern.NORM_DATE_PATTERN)));javaTimeModule.addSerializer(LocalTime.class, new LocalTimeSerializer(DateTimeFormatter.ofPattern(DatePattern.NORM_TIME_PATTERN)));javaTimeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern(DatePattern.NORM_DATETIME_PATTERN)));javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern(DatePattern.NORM_DATE_PATTERN)));javaTimeModule.addDeserializer(LocalTime.class, new LocalTimeDeserializer(DateTimeFormatter.ofPattern(DatePattern.NORM_TIME_PATTERN)));objectMapper.registerModule(javaTimeModule);return objectMapper;}
  }
  

• 2、分页器插件配置

  package com.example.spring_mybatis.config;import com.baomidou.mybatisplus.annotation.DbType;
  import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
  import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
  import org.springframework.context.annotation.Bean;
  import org.springframework.context.annotation.Configuration;/*** mybatis-plus分页插件*/
  @Configuration
  public class MybatisPlusConfig {@Beanpublic MybatisPlusInterceptor mybatisPlusInterceptor() {MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));return interceptor;}
  }
  

• 3、元数据配置,比如创建时间、更新时间、获取当前更新人等数据

  package com.example.spring_mybatis.config;import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
  import com.example.spring_mybatis.model.BaseEntity;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.ibatis.reflection.MetaObject;
  import org.springframework.stereotype.Component;import java.time.LocalDateTime;
  import java.util.Date;
  import java.util.Objects;/*** mybatis-plus元数据插件配置(更新时间,不在数据库层面做)*/
  @Component
  @Slf4j
  public class MyMetaObjectHandler implements MetaObjectHandler {/*** 插入时自动填充** @param metaObject*/@Overridepublic void insertFill(MetaObject metaObject) {if (Objects.nonNull(metaObject) && metaObject.getOriginalObject() instanceof BaseEntity) {BaseEntity baseEntity = (BaseEntity) metaObject.getOriginalObject();// 创建时间和更新时间if (Objects.isNull(baseEntity.getCreatedAt())) {baseEntity.setCreatedAt(LocalDateTime.now());}if (Objects.isNull(baseEntity.getUpdatedAt())) {baseEntity.setUpdatedAt(LocalDateTime.now());}}}/*** 更新时自动填充** @param metaObject*/@Overridepublic void updateFill(MetaObject metaObject) {if (Objects.nonNull(metaObject) && metaObject.getOriginalObject() instanceof BaseEntity) {BaseEntity baseEntity = (BaseEntity) metaObject.getOriginalObject();baseEntity.setUpdatedAt(LocalDateTime.now());}}
  }
  

三、手动搭建控制器、服务层、实体类

• 1、最终项目目录结构如下

• 2、手动创建实体类去继承BaseEntity类,在BaseEntity类中书写一些基础字段

  package com.example.spring_mybatis.model;import com.baomidou.mybatisplus.annotation.*;
  import com.fasterxml.jackson.annotation.JsonFormat;
  import com.fasterxml.jackson.annotation.JsonIgnore;
  import lombok.Data;import java.time.LocalDateTime;@Data
  public class BaseEntity {@TableId(value = "id", type = IdType.AUTO)private String id;@TableField(fill = FieldFill.INSERT)@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")private LocalDateTime createdAt;@TableField(fill = FieldFill.INSERT_UPDATE)@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")private LocalDateTime  updatedAt;@TableLogic@JsonIgnoreprivate LocalDateTime  deletedAt;
  }
  

  package com.example.spring_mybatis.model;import com.baomidou.mybatisplus.annotation.*;
  import com.fasterxml.jackson.annotation.JsonFormat;
  import com.fasterxml.jackson.annotation.JsonIgnore;
  import lombok.Data;
  import lombok.EqualsAndHashCode;
  import lombok.experimental.Accessors;import java.time.LocalDateTime;
  import java.util.Date;@Data
  @EqualsAndHashCode(callSuper = true)
  @Accessors(chain = true)
  @TableName("user")
  public class UserEntity extends BaseEntity{/*** 用户名*/private String username;/*** 密码*/private String password;/*** 状态:0是禁止,1是正常*/private Integer status;}
  

• 3、控制器内容书写

  package com.example.spring_mybatis.controller;import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
  import com.example.spring_mybatis.dto.UserDTO;
  import com.example.spring_mybatis.model.UserEntity;
  import com.example.spring_mybatis.service.IUserService;
  import com.example.spring_mybatis.utils.R;
  import lombok.extern.slf4j.Slf4j;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.web.bind.annotation.*;import java.util.List;@RestController
  @RequestMapping("/api/user")
  @Slf4j
  public class UserController {@Autowiredprivate IUserService iUserService;@PostMapping("")public R<String> createUser(@RequestBody UserDTO userDto) {log.info("进入创建用户的控制器");return this.iUserService.createUser(userDto);}@GetMapping()public R<List<UserEntity>> getUser() {List<UserEntity> list = this.iUserService.list();return R.success(list);}@DeleteMapping("/{id}")public R<String> deleteUserById(@PathVariable Long id){System.out.println("接收到参数:"+id);LambdaQueryWrapper<UserEntity> queryWrapper = new LambdaQueryWrapper<>();queryWrapper.eq(UserEntity::getId,id);boolean affected = iUserService.remove(queryWrapper);if (affected) {return R.success("删除成功");} else {return R.error("删除失败");}}
  }

• 4、服务层接口

  package com.example.spring_mybatis.service;import com.baomidou.mybatisplus.extension.service.IService;
  import com.example.spring_mybatis.dto.UserDTO;
  import com.example.spring_mybatis.model.UserEntity;
  import com.example.spring_mybatis.utils.R;public interface IUserService extends IService<UserEntity> {R<String> createUser(UserDTO userDto);
  }
  

• 5、服务层

  package com.example.spring_mybatis.service.impl;import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
  import com.example.spring_mybatis.dto.UserDTO;
  import com.example.spring_mybatis.mapper.UserMapper;
  import com.example.spring_mybatis.model.UserEntity;
  import com.example.spring_mybatis.service.IUserService;
  import com.example.spring_mybatis.utils.R;
  import org.springframework.beans.BeanUtils;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.stereotype.Service;@Service
  public class UserServiceImpl extends ServiceImpl<UserMapper, UserEntity> implements IUserService {@Autowiredprivate UserMapper userMapper;@Overridepublic R<String> createUser(UserDTO userDto) {UserEntity userEntity = new UserEntity();BeanUtils.copyProperties(userDto, userEntity);int insert = this.userMapper.insert(userEntity);if (insert == 1) {return R.success("创建成功");} else {return R.error("创建失败");}}
  }
  

• 6、mapper层的书写

  package com.example.spring_mybatis.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
  import com.example.spring_mybatis.model.UserEntity;
  import org.springframework.stereotype.Repository;@Repository
  public interface UserMapper extends BaseMapper<UserEntity> {
  }

• 7、UserMapper.xml的书写

  <?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.example.spring_mybatis.mapper.UserMapper"><!--  基础配置  --><resultMap id="BaseResultMap" type="com.example.spring_mybatis.model.UserEntity"><result column="id" property="id"/><result column="created_at" property="createdAt"/><result column="updated_at" property="updatedAt"/><result column="deleted_at" property="deletedAt"/><result column="username" property="username"/><result column="password" property="password"/><result column="status" property="status"/></resultMap>
  </mapper>

• 8、运行代码,使用postman调试是否可以创建成功

四、模板生成器的使用

• 1、官方地址

• 2、使用上面的方式要一个一个文件夹去创建比较费力,下面讲解模板生成器的使用

• 3、安装依赖包

  <!--    mybatis-plus代码生成器    -->
  <dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-generator</artifactId><version>3.5.3.1</version>
  </dependency>
  <!--    代码生成器的模板    -->
  <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-freemarker</artifactId>
  </dependency>
  

• 4、创建一个CodeGenerator的文件

  package com.example.spring_mybatis;import com.baomidou.mybatisplus.annotation.IdType;
  import com.baomidou.mybatisplus.core.exceptions.MybatisPlusException;
  import com.baomidou.mybatisplus.core.toolkit.StringUtils;
  import com.baomidou.mybatisplus.generator.AutoGenerator;
  import com.baomidou.mybatisplus.generator.FastAutoGenerator;
  import com.baomidou.mybatisplus.generator.config.*;
  import com.baomidou.mybatisplus.generator.config.builder.CustomFile;
  import com.baomidou.mybatisplus.generator.config.rules.DateType;
  import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
  import com.baomidou.mybatisplus.generator.engine.FreemarkerTemplateEngine;
  import com.example.spring_mybatis.model.BaseEntity;import java.text.MessageFormat;
  import java.util.*;public class CodeGenerator {private final static String DB_USERNAME = "root";private final static String DB_HOST = "localhost";private final static String DB_PORT = "3306";private final static String DB_PASSWORD = "123456";private final static String DB_DATABASE = "beego";private final static String PROJECT_PATH = "com/example/spring_mybatis";
  //    private final static String PROJECT_PATH = System.getProperty("user.dir");public static void main(String[] args) {System.out.println(System.getProperty("user.dir"));// 数据源配置FastAutoGenerator fastAutoGenerator = FastAutoGenerator.create(MessageFormat.format("jdbc:mysql://{0}:{1}/{2}?serverTimezone=GMT%2B8", DB_HOST, DB_PORT, DB_DATABASE), DB_USERNAME, DB_PASSWORD)// 1.全局配置.globalConfig(builder -> {builder.author("水痕")        // 设置作者
  //                            .enableSwagger()        // 开启 swagger 模式 默认值:false.disableOpenDir()       // 禁止打开输出目录 默认值:true.commentDate("yyyy-MM-dd HH:mm:ss") // 注释日期.fileOverride() // 覆盖之前的文件.dateType(DateType.ONLY_DATE)   //定义生成的实体类中日期类型 DateType.ONLY_DATE 默认值: DateType.TIME_PACK.outputDir(System.getProperty("user.dir") + "/src/main/java"); // 指定输出目录})// 2.包配置.packageConfig(builder -> {builder.parent(PROJECT_PATH.replace("/", ".")) // 父包模块名.pathInfo(getPathInfo()).controller("controller")   //Controller 包名 默认值:controller.entity("model")           //Entity 包名 默认值:entity.service("service")         //Service 包名 默认值:service.mapper("mapper")           //Mapper 包名 默认值:mapper// .other("model")//.moduleName("xxx")        // 设置父包模块名 默认值:无.pathInfo(Collections.singletonMap(OutputFile.xml, System.getProperty("user.dir") + "/src/main/resources/mapper")); // 设置mapperXml生成路径//默认存放在mapper的xml下})
  //                .injectionConfig(consumer -> {
  //                    // Map<String, String> customFile = new HashMap<>();
  //                    // DTO 下面的key会作为类名后缀，进而生成新类
                      customFile.put("DTO.java", "templates/other/dto.java.vm");
                      customFile.put("VO.java", "templates/other/vo.java.vm");
                      consumer.customFile(customFile);
  //                    String basePath = System.getProperty("user.dir");
  //                    List<CustomFile> customFiles = new ArrayList<>();
  //                    customFiles.add(new CustomFile.Builder().fileName("DTO.java")
  //                            .templatePath("templates/other/dto.java.vm")
  //                            .filePath(basePath+"/src/main/java/"+PROJECT_PATH+"/dto").build());
  //                    customFiles.add(new CustomFile.Builder().fileName("VO.java")
  //                            .templatePath("templates/other/vo.java.vm")
  //                            .filePath(basePath+"/src/main/java/"+PROJECT_PATH+"/vo").build());
  //                    consumer.customFile(customFiles);
  //
  //                })// 策略配置.strategyConfig(builder -> {builder.addInclude(scanner("表名，多个英文逗号分割").split(","))//service策略配置.serviceBuilder().formatServiceFileName("I%sService").formatServiceImplFileName("%sServiceImpl")// 实体类策略配置.entityBuilder().formatFileName("%sEntity")
  //                            .idType(IdType.ASSIGN_ID)//主键策略  雪花算法自动生成的id
  //                            .addTableFills(new Column("created_at", FieldFill.INSERT)) // 自动填充配置
  //                            .addTableFills(new Property("updated_at", FieldFill.INSERT_UPDATE)).enableLombok() //开启lombok
  //                            .logicDeleteColumnName("deleted_at")// 说明逻辑删除是哪个字段
  //                             .formatFileName("%sEntity").superClass(BaseEntity.class).addSuperEntityColumns("id", "created_at", "updated_at", "deleted_at") // 公共字段不需要抽取.enableTableFieldAnnotation()// 属性加上注解说明// 关于控制器的.controllerBuilder() //controller 策略配置.formatFileName("%sController").enableRestStyle() // 开启RestController注解// 关于mapper的.mapperBuilder()// mapper策略配置.formatMapperFileName("%sMapper")
  //                            .enableMapperAnnotation()//@mapper注解开启.formatXmlFileName("%sMapper");}).templateEngine(new FreemarkerTemplateEngine());// 使用Freemarker引擎模板，默认的是Velocity引擎模板
  //fastAutoGenerator.execute();System.out.println("生成模板成功");}private 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);if (scanner.hasNext()) {String ipt = scanner.next();if (StringUtils.isNotEmpty(ipt)) {return ipt;}}throw new MybatisPlusException("请输入正确的" + tip + "！");}/*** 配置生成路径** @return*/private static Map<OutputFile, String> getPathInfo() {Map<OutputFile, String> pathInfo = new HashMap<>();String path = "/src/main/java/" + PROJECT_PATH;pathInfo.put(OutputFile.entity, System.getProperty("user.dir") + path + "/model");pathInfo.put(OutputFile.mapper, System.getProperty("user.dir") + path + "/mapper");pathInfo.put(OutputFile.service, System.getProperty("user.dir") + path + "/service");pathInfo.put(OutputFile.serviceImpl, System.getProperty("user.dir") + path + "/service/impl");pathInfo.put(OutputFile.controller, System.getProperty("user.dir") + path + "/controller");pathInfo.put(OutputFile.xml, System.getProperty("user.dir") + "/src/main/resources/mapper");return pathInfo;}
  }
  

• 5、运行文件输入表名,一件生成上面的代码文件

五、自定义模板来实现简单的增删改查操作

• 1、导入依赖包

  <!--   数据校验     -->
  <dependency><groupId>org.hibernate.validator</groupId><artifactId>hibernate-validator</artifactId>
  </dependency>
  <!--    mybatis-plus代码生成器    -->
  <dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-generator</artifactId><version>3.5.3.1</version>
  </dependency>
  <!-- 自动生成模板需要 -->
  <dependency><groupId>org.apache.velocity</groupId><artifactId>velocity-engine-core</artifactId><version>2.3</version>
  </dependency>
  <!--    代码生成器的模板    -->
  <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-freemarker</artifactId>
  </dependency>
  

• 2、直接参考代码,代码见