這篇文章主要介紹了教你如何寫springboot接口,Spring?Boot是由Pivotal團(tuán)隊提供的全新框架，其設(shè)計目的是用來簡化新Spring應(yīng)用的初始搭建以及開發(fā)過程。該框架使用了特定的方式來進(jìn)行配置，從而使開發(fā)人員不再需要定義樣板化的配置,需要的朋友可以參考y一下

首先要明白數(shù)據(jù)的流通方向：

數(shù)據(jù)的觸發(fā)是前端請求后端引起的，遵循傳統(tǒng)的mvc規(guī)范的話我們需要pojo mapper service controller 四個層次，Pojo 是于數(shù)據(jù)庫中字段直接對應(yīng)的

在線搭建一個springboot項目

https://start.spring.io/

其中需要加入的四個依賴

點擊確定把沒有用的文件刪除最后保留一下兩個：

開始編寫接口實現(xiàn)

pon.xml

<?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>2.6.2</version>
?? ??? ?<relativePath/> <!-- lookup parent from repository -->
?? ?</parent>
?? ?<groupId>com.example</groupId>
?? ?<artifactId>demo</artifactId>
?? ?<version>0.0.1-SNAPSHOT</version>
?? ?<name>demo</name>
?? ?<description>Demo project for Spring Boot</description>
?? ?<properties>
?? ??? ?<java.version>1.8</java.version>
?? ?</properties>
?? ?<dependencies>
?? ??? ?<dependency>
?? ??? ??? ?<groupId>org.springframework.boot</groupId>
?? ??? ??? ?<artifactId>spring-boot-starter-web</artifactId>
?? ??? ?</dependency>
?? ??? ?<dependency>
?? ??? ??? ?<groupId>org.mybatis.spring.boot</groupId>
?? ??? ??? ?<artifactId>mybatis-spring-boot-starter</artifactId>
?? ??? ??? ?<version>2.2.1</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>org.springframework.boot</groupId>
?? ??? ??? ?<artifactId>spring-boot-starter-test</artifactId>
?? ??? ??? ?<scope>test</scope>
?? ??? ?</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>

application.yml

spring:
? datasource:
? ? driver-class-name: com.mysql.cj.jdbc.Driver
? ? url: jdbc:mysql://localhost:3306/test?useUnicode=true&useSSL=false&characterEncoding=utf8&serverTimezone=Asia/Shanghai
? ? username: root
? ? password: 123456
server:
? port: 8001

持久層：

package com.example.demo.entity;

import lombok.Data;

@Data
public class User {
? ? private Integer id;
? ? private String name;
? ? private String address;
? ? private Integer age;
? ? private String sex;
? ? private String phone;

}

這里我們引入了 lombok 不需要寫get和set方法簡化代碼

<dependency>
? ? <groupId>org.projectlombok</groupId>
? ? <artifactId>lombok</artifactId>
? ? <version>1.16.10</version>
? ? <scope>provided</scope>
</dependency>

mapper層

package com.example.demo.mapper;

import com.example.demo.entity.User;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;

import java.util.List;

public interface UserMapper {

? ? @Select("select * from user")
? ? List<User> findAll();

? ? @Update("INSERT INTO `user` (`name`, `address`, `age`, `sex`, `phone`) VALUES (#{name},#{address},#{age},#{sex},#{phone});")
? ? @Transactional
? ? void save(User user);


? ? @Update("update user set name=#{name} , address=#{address}, age=#{age}, sex=#{sex},phone=#{phone} where id =#{id}")
? ? @Transactional
? ? void updateById(User user);


? ? @Delete("delete from user where id =#{id}")
? ? @Transactional
? ? void deleteById(Long id);

? ? @Select("select * from user where id =#{id}")
? ? User findById(Long id);


? ? @Select("select * from user limit #{offset},#{pageSize}")
? ? List<User> findByPage(Integer offset, Integer pageSize);

? ? @Select("select count(id) from user")
? ? Integer countUser();
}

controller

package com.example.demo.controller;

import com.example.demo.entity.User;
import com.example.demo.mapper.UserMapper;
import com.example.demo.vo.Page;
import org.apache.ibatis.annotations.Delete;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;
import java.util.List;

@RestController
@RequestMapping("/user")
public class UserController {
? ??
? ? @Resource
? ? UserMapper userMapper;
? ? @GetMapping
? ? public List<User> getUser() {
? ? ? ? return userMapper.findAll();
? ? }

? ? @PostMapping
? ? public String addUser(@RequestBody User user){
? ? ? ? //把前端傳過來的數(shù)據(jù)轉(zhuǎn)化為user實體類的對象插入到數(shù)據(jù)庫中
? ? ? ? userMapper.save(user);
? ? ? ? return "success";


? ? }
? ? @PutMapping
? ? public String updateUser(@RequestBody User user){
? ? ? ? userMapper.updateById(user);
? ? ? ? return "success";
? ? }

? ? @DeleteMapping("/{id}") ?//一一對相應(yīng)的關(guān)系
? ? public String deleteUser(@PathVariable("id") Long id){
? ? ? ? //注解是循序json回傳帶有id
? ? ? ? userMapper.deleteById(id);
? ? ? ? return "success";
? ? }
? ? @GetMapping("/{id}") ?//把返回的結(jié)果 返回出來 包裝成一個user對象
? ? public User findById(@PathVariable("id") Long id){
? ? ? ? //注解是循序json回傳帶有id
? ? ? ? return userMapper.findById(id);
? ? }

? ? @GetMapping("/page")
? ? public Page<User> findByPage(@RequestParam(defaultValue = "1") Integer pageNum,
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?@RequestParam(defaultValue = "10") Integer pageSize) {
? ? ? ? Integer offset = (pageNum - 1) * pageSize;
? ? ? ? List<User> userData = userMapper.findByPage(offset, pageSize);
? ? ? ? Page<User> page = new Page<>();
? ? ? ? page.setData(userData);

? ? ? ? Integer total = userMapper.countUser();
? ? ? ? page.setTotal(total);
? ? ? ? page.setPageNum(pageNum);
? ? ? ? page.setPageSize(pageSize);
? ? ? ? return page;
? ? }

}