Spring Data Jpa操作数据库及其查询操作实现

初始化工程的目录结构：

1、链接数据库的方法

          配置application.yml文件即可；内容如下：

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/library
    username: root
    password: root
  jpa:
    hibernate:
      ddl-auto: update #使用create可以自动创建一个表，且每次运行都会重新创建。所以第一次运行用create，后面就要改成update
    show-sql: true #让sql语句在控制台中打印出来，方便我们调试

server:
  port: 8088

2、spring data jpa 查询数据库

1、创建实体类：

package com.supermu.springboot.entity;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
public class Book {
    @Id
    @GeneratedValue
    private Integer id;

    private String name;

    private String author;

    private String publish;

    private Integer pages;

    private Float price;

    private Integer bookcaseid;

    private Integer abled;

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getPublish() {
        return publish;
    }

    public void setPublish(String publish) {
        this.publish = publish;
    }

    public Integer getPages() {
        return pages;
    }

    public void setPages(Integer pages) {
        this.pages = pages;
    }

    public Float getPrice() {
        return price;
    }

    public void setPrice(Float price) {
        this.price = price;
    }

    public Integer getBookcaseid() {
        return bookcaseid;
    }

    public void setBookcaseid(Integer bookcaseid) {
        this.bookcaseid = bookcaseid;
    }

    public Integer getAbled() {
        return abled;
    }

    public void setAbled(Integer abled) {
        this.abled = abled;
    }
}

2、创建实体操作的repository

package com.supermu.springboot.repository;

import com.supermu.springboot.entity.Book;
import org.springframework.data.jpa.repository.JpaRepository;

import java.util.List;

public interface BookRepository extends JpaRepository<Book, Integer> {

    List<Book> findByName(String name);

    List<Book> findByNameAndAuthor(String name, String author);
}

3、创建逻辑层service

package com.supermu.springboot.service;

import com.supermu.springboot.entity.Book;

import java.util.List;

public interface BookService {
    public List<Book> findAll();

    public List<Book> findByName(String name);

    List<Book> findByNameAndAuthor(String name, String author);
}

package com.supermu.springboot.service.impl;

import com.supermu.springboot.entity.Book;
import com.supermu.springboot.repository.BookRepository;
import com.supermu.springboot.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service("bookService")
public class BookServiceImpl implements BookService {

    @Autowired
    private BookRepository bookRepository;

    @Override
    public List<Book> findAll() {
        return bookRepository.findAll();
    }

    @Override
    public List<Book> findByName(String name) {
        return bookRepository.findByName(name);
    }

    @Override
    public List<Book> findByNameAndAuthor(String name, String author) {
        return bookRepository.findByNameAndAuthor(name, author);
    }
}

4、实现控制层

package com.supermu.springboot.controller;

import com.supermu.springboot.entity.Book;
import com.supermu.springboot.repository.BookRepository;
import com.supermu.springboot.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;
import java.util.Optional;

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

    @Autowired
    private BookRepository bookRepository;

    @Autowired
    private BookService bookService;

    @GetMapping("/list")
    public List<Book> list() {
        return bookRepository.findAll();
    }

    @GetMapping("/id")
    public Optional<Book> getid(@RequestParam("id") Integer id) {
        return bookRepository.findById(id);
    }

    @GetMapping("/name")
    public List<Book> getByName(@RequestParam("name") String name) {
        return bookService.findByName(name);
    }

    @GetMapping("/two")
    public List<Book> getByNameAndAuthor(@RequestParam("name") String name, @RequestParam("author") String author) {
        return bookService.findByNameAndAuthor(name, author);
    }
}

5、接口测试：http://127.0.0.1:8088/book/two?name=%E6%88%91%E4%BB%AC%E4%BB%A8&author=%E6%9D%A8%E7%BB%9B