开启掘金成长之旅！这是我参与「掘金日新计划 · 2 月更文挑战」的第 7 天，点击查看活动详情
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。
把你文件中的dependencies下的包都替换成我这个。
<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>
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
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。
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
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;
}
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);
}
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);
}
}
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);
}
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>
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");
}
}
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);
}
}
