基于SpringBoot+Mybatis-Plus的快速入门案例

图书管理系统源码已上传Gitee 源码地址

参考视频 : 黑马程序员SpringBoot

1. 技术栈和环境配置

SpringBoot 2.6.7
Mybatis-Plus 3.4.3
Lombok 1.18
mysql 5.6
JDK 8

2.案例效果演示

2.1添加书籍
2.2 删除书籍
2.3 修改书籍
2.4 按条件查询书籍
2.5分页

3.案例分析

3.1实体类

使用Lombok快速制作实体类

@Data
//标注sql数据表名称
@TableName("t_book")
public class Books {

    private Integer id;
    private String type;
    private String name;
    private String description;
    
}

3.2数据层

整合MybatisPlus

application.yml文件

#端口号
server:
  port: 80

#数据源
spring:
  datasource:
    druid:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/db4?serverTimezone=UTC
      username: root
      password: 

#mybatis-plus 使用数据库自增算法
mybatis-plus:
  global-config:
    db-config:
      id-type: auto
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

#开启MP日志并设置输出方式为标准输出(输出控制台) 用于测试

配置MP的分页拦截器

@Configuration
public class MPConfig {
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor(){
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor());

        return interceptor;
    }

}

MySQL数据表——t_book

CREATE TABLE t_book(
id INT NOT NULL AUTO_INCREMENT,
TYPE VARCHAR(20),
NAME VARCHAR(20),
description VARCHAR(20),
PRIMARY KEY (id)
)ENGINE=INNODB  DEFAULT CHARSET=utf8;

3.3业务层/服务层

基于MyBatisPlus进行增量开发

IBookService接口类

注：此接口继承MybatisPlus提供的IService接口，默认实现了许多业务操作

public interface IBookService extends IService<Books> {

  boolean saveBook(Books books);

  boolean modify(Books books);

  boolean delete(Integer id);

  IPage<Books> getPage(int currentPage, int pageSize);

  IPage<Books> getPage(int currentPage, int pageSize,Books books);

}

BookServiceImpl实现类

注：此类继承ServiceImpl<BookDao,Books>类，参数为接口和实体类，代表映射关系

@Service
public class BookServiceImpl extends ServiceImpl<BookDao,Books> implements IBookService {

    @Autowired
    private BookDao bookDao;

    @Override
    public boolean saveBook(Books books) {
        return bookDao.insert(books) > 0;
    }

    @Override
    public boolean modify(Books books) {
        return bookDao.updateById(books) > 0;
    }

    @Override
    public boolean delete(Integer id) {
        return  bookDao.deleteById(id) > 0;
    }

    @Override
    public IPage<Books> getPage(int currentPage, int pageSize) {
       IPage page = new Page(currentPage,pageSize);

       bookDao.selectPage(page,null);
       return page;
    }

    @Override
    public IPage<Books> getPage(int currentPage, int pageSize, Books books) {
        LambdaQueryWrapper<Books> lqw = new LambdaQueryWrapper<>();
        lqw.like(Strings.isNotEmpty(books.getType()), Books::getType,books.getType());
        lqw.like(Strings.isNotEmpty(books.getName()), Books::getName,books.getName());
        lqw.like(Strings.isNotEmpty(books.getDescription()), Books::getDescription,books.getDescription());
        IPage page = new Page(currentPage,pageSize);

        bookDao.selectPage(page,lqw);
        return page;

    }
}

3.4表现层/控制层

基于Restful风格

BookController类

@RestController
@RequestMapping("/books")
public class BookController {

    @Autowired
    private IBookService bookService;

    @GetMapping
    public ResultMessage getAll() {
        return new ResultMessage(true,bookService.list());
    }

    @PostMapping
    public ResultMessage save(@RequestBody Books books) {
     return new ResultMessage(bookService.saveBook(books));

    }

    @DeleteMapping("{id}")
    public ResultMessage delete(@PathVariable Integer id) {
        return new ResultMessage(bookService.delete(id));
    }

    @PutMapping
    public ResultMessage update(@RequestBody Books books) {
        return  new ResultMessage(bookService.modify(books));
    }

    @GetMapping("{id}")
    public ResultMessage getById(@PathVariable Integer id) {
        //true表示查询到数据了 可能为空
        return new ResultMessage(true,bookService.getById(id));
    }

    /**
     * 分页  条件查询
     * @param currentPage
     * @param pageSize
     * @param books
     * @return
     */

    @GetMapping("{currentPage}/{pageSize}")
    public ResultMessage getPage(@PathVariable int currentPage, @PathVariable int pageSize, Books books) {
          IPage<Books> page = bookService.getPage(currentPage, pageSize,books);
          //解决删除某页唯一一条数据时，出现空页面的问题
          if (currentPage > page.getPages()){
              page = bookService.getPage((int) page.getPages(),pageSize,books);
          }
        return new ResultMessage(true, page);
    }

}

表现层消息一致性处理，前后端数据协议

ResultMessage类，消息统一处理

@Data
public class ResultMessage {

    private Boolean flag;
    private Object data;

    private String message;

    public ResultMessage(){

    }
    public ResultMessage(Boolean flag){
        this.flag = flag;
    }

    public ResultMessage(Boolean flag, Object data){
        this.flag = flag;
        this.data = data;
    }


    public ResultMessage(String message){
        this.flag = flag;
        this.message = message;
    }

    public ResultMessage(Boolean flag, String message){
        this.flag = flag;
        this.message = message;
    }
}

异常处理

@RestControllerAdvice
public class ExceptionAdvice {

    //拦截异常
    @ExceptionHandler
    public ResultMessage doException(Exception e){
        e.printStackTrace();
        return new ResultMessage("服务器故障,稍后再试");
    }

}

3.5页面开发

基于VUE+ElementUI

页面数据处理、页面消息处理

books.html （部分代码）

<script>
    var vue = new Vue({
        el: '#app',
        data: {
            dataList: [],//当前页要展示的列表数据
            dialogFormVisible: false,//添加表单是否可见
            dialogFormVisible4Edit: false,//编辑表单是否可见
            formData: {},//表单数据
            rules: {//校验规则
                type: [{required: true, message: '图书类别为必填项', trigger: 'blur'}],
                name: [{required: true, message: '图书名称为必填项', trigger: 'blur'}]
            },
            pagination: {   //分页相关模型数据
                currentPage: 1,   //当前页码
                pageSize: 10,   //每页显示的记录数
                total: 0,  //总记录数
                type:"",
                name:"",
                description:""
            }
        },

        //钩子函数，VUE对象初始化完成后自动执行
        created() {
            this.getAll();
        }
         }) 
   </script>