❤️轻松带你实现SpringBoot+Mybatis对数据库的增删改查（最详细的讲解，拿来即用）❤️

野性酷女 2022-09-13 08:48 43阅读 0赞

# 一、项目目录 #

![image-20210928134306510][]

# 二、添加依赖 #

首先要新建一个SpringBoot项目，要选择web的项目。然后初始化完项目后，我们在pom.xml中添加需要的依赖。

把你的配置下的依赖换成我这个。

<dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.2.0</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.1.9</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>io.springfox</groupId>
                <artifactId>springfox-boot-starter</artifactId>
                <version>3.0.0</version>
            </dependency>
        </dependencies>
    
      <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
            <resources>
                <resource>
                    <directory>src/main/java</directory>
                    <includes>
                        <include>**/*.xml</include>
                    </includes>
                </resource>
            </resources>
        </build>

# 三、代码编写 #

总的流程是建立数据库 -> 连接数据库 -> 创建对象类 -> 创建业务接口 -> 业务实现类 -> 数据库接口类 -> xml数据库操作 -> 接口类

## 1、创建数据库 ##

创建一个数据库为book

Create database book;

创建表名也暂为book吧

DROP TABLE IF EXISTS `book`;
    CREATE TABLE `book` (
      `id` int NOT NULL AUTO_INCREMENT,
      `name_` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
      `author` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

同时插入一点数据吧

INSERT INTO `book` VALUES ('1', '121', '张三');
    INSERT INTO `book` VALUES ('3', 'ewew', '小王');
    INSERT INTO `book` VALUES ('4', 'ewew', '小王1');

到此数据库准备完毕，接下来我们将项目与数据库配置连接。

## 2、配置连接 ##

打开项目，找到项目下的resources文件夹，然后就会看到application.properties文件，我这里改为了yaml文件作为配置文件。

spring:
      datasource:
        url: jdbc:mysql://localhost:3306/book?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
        username: root   //换成你的用户名
        password: 123456 //换成你的密码
        driver-class-name: com.mysql.cj.jdbc.Driver

## 3、创建对象类 ##

在model的包下面，我们创建一个实体类为`Book.java`

因为我们引入了Lombok依赖，所有只要加一个@Data注解就不用写get/set方法了。节省代码量

package com.mjc.book.model;
    
    import lombok.Data;
    
    /** * 实体类，对应数据库表 * @author admin */
    @Data  
    public class Book { 
        private int id;
        private String bookName;
        private String author;
    
    }

## 4、创建业务接口 ##

在包service下面增加一个`BookService.java`类，主要放业务的接口，可供controller层调用。

package com.mjc.book.service;
    
    import com.mjc.book.model.Book;
    
    import java.util.List;
    
    /** * controller层调用业务层 * @author admin */
    public interface BookService { 
    
        /** * 查询书 * @return */
        List<Book> findAll();
    
        /** * 添加书 * @param book */
        void creatBook(Book book);
    
        /** * 更新书 * @param book */
        void updateBook(Book book);
    
        /** * 删除书 * @param id */
        void deleteBook(int id);
    
    }

## 5、业务实现类 ##

在service包里再新建一个Impl包，主要放业务实现类，增加一个`BookServiceImpl.java`类，继承service接口。

package com.mjc.book.service.Impl;
    
    import com.mjc.book.mapper.BookMapper;
    import com.mjc.book.model.Book;
    import com.mjc.book.service.BookService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    import java.util.List;
    
    /** * 业务实现层 * @author admin */
    @Service
    public class BookServiceImpl implements BookService { 
    
        @Autowired
        BookMapper bookMapper;
    
        @Override
        public List<Book> findAll() { 
            return bookMapper.findAll();
        }
    
        @Override
        public void creatBook(Book book) { 
            bookMapper.insert(book);
        }
    
        @Override
        public void updateBook(Book book) { 
            bookMapper.update(book);
        }
    
        @Override
        public void deleteBook(int id) { 
            bookMapper.delete(id);
        }
    
    }

## 6、 数据库接口类 ##

在mapper包下增加一个接口类`BookMapper.java` 类

package com.mjc.book.mapper;
    
    import com.mjc.book.model.Book;
    import org.apache.ibatis.annotations.Mapper;
    
    import java.util.List;
    
    /** * 数据库查询接口mapper相当于dao层 * @author admin */
    @Mapper
    public interface BookMapper { 
    
        /** * 查询全部图书 * @return */
        List<Book> findAll();
    
        /** * 添加图书 * @param book */
        void insert(Book book);
    
        /** * 更新图书 * @param book */
        void update(Book book);
    
        /** * 删除书 * @param id * @return */
        int delete(int id);
    
    }

## 7、xml数据库操作 ##

同样，在mapper包下增加一个xml配置`BookMapper.xml` , BookMapper接口的方法就是xml中增删改查对应的id。

<?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.mjc.book.mapper.BookMapper">
        <resultMap id="BaseResultMap" type="com.mjc.book.model.Book">
            <result column="id" jdbcType="INTEGER" property="id"/>
            <result column="name_" jdbcType="VARCHAR" property="bookName"/>
            <result column="author" jdbcType="VARCHAR" property="author"/>
        </resultMap>
    
        <select id="findAll" resultMap="BaseResultMap">
            select * from book;
        </select>
    
        <insert id="insert" parameterType="com.mjc.book.model.Book" useGeneratedKeys="true" keyProperty="id">
            INSERT INTO book (name_, author)
            VALUES(#{bookName}, #{author})
        </insert>
    
        <update id="update" parameterType="com.mjc.book.model.Book">
            update book
            <set>
                name_ = #{bookName},
                author = #{author}
            </set>
            WHERE id = #{id}
        </update>
    
        <delete id="delete" parameterType="java.lang.Integer">
            delete from book where id = #{id, jdbcType=INTEGER}
        </delete>
    
    </mapper>

## 8、接口类 ##

在写接口类之前，我们要先写一个返回类，对返回的格式进行统一的封装。在util包中新建一个`Result.java`

package com.mjc.book.util;
    
    import lombok.Data;
    
    import java.io.Serializable;
    
    /** * 统一返回格式 */
    @Data
    public class Result implements Serializable { 
    
        //响应码
        private int code;
    
        private Object obj;
    
        public Result(int code) { 
            this.code = code;
        }
    
        public Result() { 
    
        }
    
        public Result success(int code, Object object){ 
           Result result = new Result();
               result.setCode(code);
               result.setObj(object);
               return result;
        }
    
        public int getCode() { 
            return code;
        }
    
        public void setCode(int code) { 
            this.code = code;
        }
    
    }

然后再新建一个controller包，在包中新建一个`controller.java`类。

package com.mjc.book.controller;
    
    import com.mjc.book.model.Book;
    import com.mjc.book.service.BookService;
    import com.mjc.book.util.Result;
    import io.swagger.annotations.Api;
    import io.swagger.annotations.ApiImplicitParam;
    import io.swagger.annotations.ApiImplicitParams;
    import io.swagger.annotations.ApiOperation;
    import org.springframework.beans.factory.annotation.Autowired;
    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.RequestBody;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.ResponseBody;
    import org.springframework.web.bind.annotation.RestController;
    
    import java.util.List;
    
    /** * 接口层，供前端调用 * @author admin */
    @Api(tags = "图书管理" )
    @RestController
    @RequestMapping(value = "/book")
    public class BookController { 
    
        @Autowired
        BookService bookService;
    
        /** * 获取所有的书 * @return */
        @ApiOperation(value = "获取所有的书", notes = "")
        @GetMapping(value = "/list")
        public Result bookList(){ 
            List<Book> all = bookService.findAll();
            return new Result().success(200, all);
        }
    
        /** * 添加图书 * @param book * @return */
        @ApiOperation(value = "添加图书", notes = "")
        @PostMapping(value = "/save")
        public Result bookSave(@RequestBody  Book book){ 
            bookService.creatBook(book);
            return new Result().success(200, "成功");
        }
    
        /** * 更新图书 * @param book * @return */
        @ApiOperation(value = "更新图书", notes = "")
        @PostMapping(value = "/update")
        public Result bookUpdate(@RequestBody Book book){ 
            bookService.updateBook(book);
            return new Result().success(200, "成功");
        }
    
        /** * 删除图书 * @param id * @return */
        @ApiOperation(value = "删除图书", notes = "")
        @PostMapping(value = "/delete/{id}")
        public Result bookDelete(@PathVariable(value = "id") int id){ 
            bookService.deleteBook(id);
            return new Result().success(200, "成功");
        }
        
    }

## 9、接入Swagger ##

我这里引入了Swagger接口文档，依赖已经在前面添加了，现在你要在启动类上加一个注解即可。

package com.mjc.book;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import springfox.documentation.oas.annotations.EnableOpenApi;
    
    @EnableOpenApi
    @SpringBootApplication
    public class BookApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(BookApplication.class, args);
        }
    
    }

**源码我已上传到gitee上，地址为：https://gitee.com/xyhwh/book-demo**

[image-20210928134306510]: /images/20220828/cfccdba512bb4b41aab418e93ce926d2.png