Springboot整合mybatisplus实战

Springboot整合mybatisplus，纯后端，验证结果是通过postman调用的，记录一下

1、建表语句以及初始化数据脚本

CREATE TABLE `tbl_book` (
  `id` int NOT NULL AUTO_INCREMENT,
  `type` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
  `name` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
  `description` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=10014 DEFAULT CHARSET=utf8

INSERT INTO `tbl_book` VALUES (10000, '计算机理论', 'Java编程思想（第4版）', 'Java学习经典,殿堂级著作！赢得了全球程序员的广泛赞誉。');
INSERT INTO `tbl_book` VALUES (10001, '计算机理论', '计算机组成原理', '资深的计算机体系结构教育家Alan Clements博士编写，涵盖计算机系统的组成和体系结构的基本概念、指令系统以及处理器实现等涉及计算机组成原理课程的内容。');
INSERT INTO `tbl_book` VALUES (10002, '程序设计', 'C++ Primer Plus 第6版 中文版', 'C++程序设计经典教程，畅销30年的C++大百科全书全新升级，经典C++入门教程十年新版再现\')');
INSERT INTO `tbl_book` VALUES (10003, '程序设计', 'RocketMQ技术内幕：RocketMQ架构设计与实现原理（第2版）', '畅销书升级，RocketMQ创始人高度评价，深入源码分析技术架构和实现原理，打造高性能、高可用、高吞吐量、低延迟RocketMQ');
INSERT INTO `tbl_book` VALUES (10004, '程序设计', ' 深入理解Java虚拟机：JVM高级特性与实践（第3版）', '周志明虚拟机新作，第3版新增内容近50%，5个维度全面剖析JVM，大厂面试知识点全覆盖。与 Java编程思想、Effective Java、Java核心技术 堪称：Java四大名著');
INSERT INTO `tbl_book` VALUES (10005, '历史', '见识城邦·人类简史：从动物到上帝（新版）', '以色列新锐历史学家尤瓦尔·赫拉利代表作，第十届文津图书奖获奖作品');
INSERT INTO `tbl_book` VALUES (10006, '历史', '中国通史', '吕思勉先生写给普通读者的中国通史入门书，用白话文写成的中国通史，把历史从“帝王的家谱”转变为人类的进化史');
INSERT INTO `tbl_book` VALUES (10007, '哲学', '理想国（柏拉图代表作）', '奠定西方哲学史的源流之作。2021新译本，以斯灵斯校勘本为底本，遵照“字对字”的原则，从古希腊原文直译，兼顾准确性和语言通顺性，助你读懂理想国。');
INSERT INTO `tbl_book` VALUES (10008, '哲学', '苏格拉底的申辩', '《柏拉图注疏集:苏格拉底的申辩》记述的是公元前399年，一个叫莫勒图斯的年轻人在雅典状告哲学家苏格拉底，说他不信城邦诸神，引进新的精灵之事，败坏青年。 于是，苏格拉底被传讯，在500人组成的陪审团面前作了著名的申辩。');
INSERT INTO `tbl_book` VALUES (10009, '文学', '鲁迅全集', '大师全集，完整收录，鲁迅毕生之心血尽归于此。\r\n\r\n　　鲁迅是中国20世纪的文学家、思想家、革命家，中国近代文学巨匠。他早年留学于日本，后来弃医从文，他用笔耕不辍的文字为新一代青年们指引方向，在国内外思想文化领域有着极高的声誉。');
INSERT INTO `tbl_book` VALUES (10010, '文学', '人间清醒', '茅盾文学奖获得者梁晓声2021全新力作');
INSERT INTO `tbl_book` VALUES (10011, '经济', '八次危机：中国的真实经验1949-2009', '著名“三农”专家温铁军，用经济的独特视角，重新审视中国的1949-2009，历史给我了我们怎样的真实经验？');

2、项目目录

 3、pom文件

<?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>2.1.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>springboot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>8</java.version>
    </properties>

    <dependencies>
        <!--web-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--mysql-connector-->
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.20</version>
        </dependency>

        <!--lombok-->
        <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-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.1.1</version>
        </dependency>
        <!--druid-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.2.6</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>

4、application文件

spring:
  datasource:
    druid:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/myproject?serverTimezone=UTC
      username: root
      password: root
mybatis-plus:
  global-config:
    db-config:
      table-prefix: tbl_
      id-type: auto
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl  #开启MP运行日志信息

5、PO类以及VO类

package com.example.po;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Book {
    private Integer id;
    private String type;
    private String name;
    private String description;
}

package com.example.vo;
/**
 * 供页面显示使用的类
 */

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;


@Data
@AllArgsConstructor
@NoArgsConstructor
public class BookVo {
    private String type;
    private String name;
    private String description;
}

6、Dao层

package com.example.dao;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.po.Book;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Component;

@Mapper
@Component
public interface BookDao extends BaseMapper<Book> {
}

7、service以及实现类

package com.example.service;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.IService;
import com.example.po.Book;

/**
 * 基于 mybatisplus 实现CRUD快速开发
 */
public interface IBookService extends IService<Book> {
    IPage<Book> getPage(Integer currentPage,Integer pageSize);
    IPage<Book> getPage(Integer currentPage,Integer pageSize,Book book);
}

package com.example.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.dao.BookDao;
import com.example.po.Book;
import com.example.service.IBookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;

@Service
public class IBookServiceImpl extends ServiceImpl<BookDao, Book> implements IBookService {
    @Autowired
    private BookDao bookDao;

    @Override
    public IPage<Book> getPage(Integer currentPage, Integer pageSize) {
        Page<Book> page = new Page<>(currentPage,pageSize);
        bookDao.selectPage(page,null);
        return page;
    }

    @Override
    public IPage<Book> getPage(Integer currentPage, Integer pageSize, Book book) {
        LambdaQueryWrapper<Book> queryWrapper = new LambdaQueryWrapper<Book>();
        queryWrapper.like(!StringUtils.isEmpty(book.getType()),Book::getType,book.getType());
        queryWrapper.like(!StringUtils.isEmpty(book.getName()),Book::getName,book.getName());
        queryWrapper.like(!StringUtils.isEmpty(book.getDescription()),Book::getDescription,book.getDescription());
        Page<Book> page = new Page<>(currentPage,pageSize);
        bookDao.selectPage(page,queryWrapper);
        return page;
    }
}

8、controller层

package com.example.controller;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.example.global.PlatErrorCodeEnum;
import com.example.po.Book;
import com.example.global.Response;
import com.example.global.ResponseBuilder;
import com.example.service.IBookService;
import com.example.vo.BookVo;
import org.springframework.beans.BeanUtils;
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.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;
import java.util.stream.Collectors;

@RestController
@RequestMapping("/books")
public class BookController {
    @Autowired
    private IBookService bookService;

    //查询所有数据
    @GetMapping
    public Response<List<BookVo>> getBooks(){
        List<BookVo> bookList = bookService.list().stream().map(po -> {
            BookVo vo = new BookVo();
            //将两个字段相同的对象进行属性值的复制
            BeanUtils.copyProperties(po, vo);
            return vo;
        }).collect(Collectors.toList());
        return ResponseBuilder.buildNormalResponse(bookList);


    }

    //添加数据
    @PostMapping("/save")
    public Response<Boolean> saveBook(@RequestBody Book book){
        Boolean flag = bookService.save(book);
        return flag == true ? ResponseBuilder.buildNormalResponse() : ResponseBuilder.buildErrorResponse(PlatErrorCodeEnum.ADD_DATA_FAILED);
    }

    @PutMapping("/update")
    public Response<Boolean> updateBook(@RequestBody Book book){
        boolean flag = bookService.updateById(book);
        return flag == true ? ResponseBuilder.buildNormalResponse() : ResponseBuilder.buildErrorResponse(PlatErrorCodeEnum.UPDATE_DATA_FAILED);
    }
    //查询单个数据
    @GetMapping("{id}")
    public Response<BookVo> getBookById(@PathVariable Integer id){
        Book book = bookService.getById(id);
        BookVo vo = new BookVo();
        BeanUtils.copyProperties(book,vo);
        return ResponseBuilder.buildNormalResponse(vo);
    }
    //删除单个数据
    @DeleteMapping("{id}")
    public Response<Boolean> deleteBook(@PathVariable Integer id){
        boolean flag = bookService.removeById(id);
        return flag == true ? ResponseBuilder.buildNormalResponse() : ResponseBuilder.buildErrorResponse(PlatErrorCodeEnum.DELETE_DATA_FAILED);
    }

    //分页查询数据
    @GetMapping("{currentPage}/{pageSize}")
    public Response<List<BookVo>> getBooksByPage(@PathVariable Integer currentPage,@PathVariable Integer pageSize){
        IPage<Book> page = bookService.getPage(currentPage,pageSize);
        //避免查出来所有的数据，增加一个vo类，只展示需要的字段
        List<BookVo> bookVos = page.getRecords().stream().map(po -> {
            BookVo vo = new BookVo();
            //将两个字段相同的对象进行属性值的复制
            BeanUtils.copyProperties(po, vo);
            return vo;
        }).collect(Collectors.toList());
        return ResponseBuilder.buildNormalResponse(bookVos);
    }

}

9、为了给前端返回统一的值，再加一些优化

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package com.example.global;

public enum PlatErrorCodeEnum {

	ADD_DATA_FAILED("10000", "添加数据失败"),
    UPDATE_DATA_FAILED("10001", "更新数据失败"),
    DELETE_DATA_FAILED("10001", "删除数据失败"),



    ;

    public static final String ERROR_CODE="000";

    private String code;
    private String message;

    PlatErrorCodeEnum(String code, String message) {
        this.code = code;
        this.message = message;
    }

	public String getCode() {
		return code;
	}

	public String getMessage() {
		return message;
	}

}

package com.example.global;

import lombok.Data;
import lombok.ToString;

import java.io.Serializable;

@Data
@ToString(callSuper = true)
public class Response<T> implements Serializable {

	private static final long serialVersionUID = -2644259941898334897L;

	private String returnCode;
	private String returnMsg;
	private T returnData;

	public Response(){

	}

	public Response(String returnCode){
		this.returnCode = returnCode;
	}

	public Response(String returnCode, String returnMsg){
		this.returnCode = returnCode;
		this.returnMsg = returnMsg;
	}

	public Response(String returnCode, String returnMsg, T returnData){
		this.returnCode = returnCode;
		this.returnMsg = returnMsg;
		this.returnData = returnData;
	}

	public T getReturnData() {
		return returnData;
	}

	public Response<T> setReturnData(T returnData) {
		this.returnData = returnData;
		return this;
	}
}

package com.example.global;


/**
 * 构造响应结果
 */
public final class ResponseBuilder {
	/**
	 * 返回成功.
	 */
	public static final String RESPONSE_OK = "0000";
	public static final String RESPONSE_MESSAGE = "响应成功";
	
	/**
	 * 构造一个失败响应
	 */
	public static <T> Response<T> buildErrorResponse(PlatErrorCodeEnum enums) {
		Response<T> entity = new Response<>();
		entity.setReturnCode(String.valueOf(enums.getCode()));
		entity.setReturnMsg(enums.getMessage());
		return entity;
	}

	/**
	 * 构造一个失败响应
	 */
	public static <T> Response<T> buildErrorResponse(String error, String message) {
		Response<T> entity = new Response<>();
		entity.setReturnCode(error);
		entity.setReturnMsg(message);
		return entity;
	}
	
	/**
	 * 构造一个正常的没有返回数据的响应
	 */
	public static <T> Response<T> buildNormalResponse() {
		return new Response<T>(RESPONSE_OK, RESPONSE_MESSAGE);
	}

	/**
	 * 构造一个正常的有返回数据的响应
	 * @param returnData
	 * @param <T>
	 * @return
	 */
	public static <T> Response<T> buildNormalResponse(T returnData) {
		Response<T> entity = buildNormalResponse();
		entity.setReturnData(returnData);
		return entity;
	}

}

10、mybatisplus分页插件配置

package com.example.config;

/**
 * 配置mybatisplus分页插件
 */

import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@MapperScan("com.example.dao")
public class MyBatisPlusConf {
    @Bean
    public PaginationInterceptor mybatisPlusInterceptor(){
        //创建拦截器 SpringBoot 低版本用 PaginationInterceptor 高版本用 MybatisPlusInterceptor
        PaginationInterceptor interceptor = new PaginationInterceptor();
        return interceptor;

    }

}