Spring_Boot 简单例子

 第一步创建项目：

 创建项目地址：https://start.spring.io/

 接下来就下载到本地了 跟着加压

接着用idea打开：等待资源下载完成

我写了个简单的：增删改查

项目结构：

dao层:

package com.nf147.demo.dao;

import com.nf147.demo.entity.News;
import org.springframework.data.jpa.repository.JpaRepository;


public interface NewsMapper extends JpaRepository<News,Integer> {  //第一个参数是实体类，第二个是id的类型

}

entity层:

package com.nf147.demo.entity;

import javax.persistence.*;

@Entity
@Table(name = "news") //表名
public class News {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)  //标明该字段是自动增长
    private int id;
    private String title;
    private String body;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getBody() {
        return body;
    }

    public void setBody(String body) {
        this.body = body;
    }
}

service层：

package com.nf147.demo.service;

import com.nf147.demo.entity.News;

import java.util.List;

public interface NewsService {
    List<News> listAll();
    void add (News news);
    void del (int id);
    void update(News news);
}

实现服务接口：

package com.nf147.demo.service;


import com.nf147.demo.dao.NewsMapper;
import com.nf147.demo.entity.News;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class NewsServiceImp implements NewsService {

    @Autowired
    private NewsMapper newsMapper;


    @Override
    @Cacheable("listNews")
    public List<News> listAll() {
        return newsMapper.findAll();
    }

    @Override
    public void add(News news) {
        newsMapper.save(news);

    }

    @Override
    public void del(int id) {
        newsMapper.deleteById(id);
    }

    @Override
    public void update(News news) {
        newsMapper.save(news);
    }
}

controller层：

package com.nf147.demo.controller;

import com.nf147.demo.entity.News;
import com.nf147.demo.service.NewsServiceImp;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController

public class NewsController {

    @Autowired
    private NewsServiceImp newsServiceImp;

    //查询
    @RequestMapping(value = "/listNews", method = RequestMethod.GET)
    public List<News> getNews() {
        return newsServiceImp.listAll();
    }

    //添加 http://localhost:8082/listNewsAdd?title=标题&body=随便给的内容
    @RequestMapping(value = "/listNewsAdd", method = RequestMethod.GET)
    public void add(News news) {
        newsServiceImp.add(news);
    }

    //删除
    //地址栏写法 http://localhost:8082/listNewsdel?id=7
    @RequestMapping(value = "/listNewsdel", method = RequestMethod.GET)
    public void del(int id) {
        newsServiceImp.del(id);
    }

    //修改
    //地址栏写法  http://localhost:8082/listNewsupdate?id=6&title=好好&body=学习
    @RequestMapping(value = "/listNewsupdate", method = RequestMethod.GET)
    public void del(News news) {
        newsServiceImp.update(news);
    }

}

测试：

项目下载地址：https://github.com/nongzihong/Spring_Boot