本文共 7608 字，大约阅读时间需要 25 分钟。

SpringBoot整合JPA

创建工程并导入依赖

   
       
    
     4.0.0
        
    
     pers.zhang
        
    
     springboot_jpa
        
    
     1.0-SNAPSHOT
        
            
     
      org.springframework.boot
             
     
      spring-boot-starter-parent
             
     
      1.5.9.RELEASE
             
      
         
        
            
                 
      
       org.springframework.boot
                  
      
       spring-boot-starter-web
              
             
                 
      
       org.springframework.boot
                  
      
       spring-boot-starter-data-jpa
              
             
             
                 
      
       mysql
                  
      
       mysql-connector-java
                  
      
       runtime
              
             
             
                 
      
       com.alibaba
                  
      
       druid
                  
      
       1.1.9
              
         
    
   

配置文件

spring:  datasource:    type: com.alibaba.druid.pool.DruidDataSource    url: jdbc:mysql:///chapter05    username: root    password: 123456  jpa:    show-sql: true #是否打印sql    database: mysql #JPA对应的数据库    hibernate:      ddl-auto: update #无表创建表

实体类

package pers.zhang.entity;import javax.persistence.*;/** * @author zhang * @date 2019/12/18 - 21:59 *//** * @Entity 表示该类是一个实体类，在项目启动时会根据该类自动生成一张表，表的名称即@Entity注解中name的值，如果不配置name，默认表名为类名。 * * 所有的实体类都要有主键，@Id注解表示该属性是一个主键，@GeneratedValue注解表示主键自动生成，strategy表示主键的生成策略。 * * 默认情况下，生成的表中字段名称就是实体类中的属性名称，通过@Column注解可以定制生成的字段名，name可以表示该属性对应的数据表中字段的名称， * nullable表示该字段是否非空 * * @Transient 注解表示在生成数据库中的表时，该属性被忽略，即不生成对应的字段。 */@Entity(name = "t_book")public class Book {
       @Id    @GeneratedValue(strategy = GenerationType.IDENTITY)    private Integer id;    @Column(name = "book_name", nullable = false)//nullable是否非空    private String name;    private String author;    private Float price;    @Transient    private String description;    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 Float getPrice() {
           return price;    }    public void setPrice(Float price) {
           this.price = price;    }    public String getDescription() {
           return description;    }    public void setDescription(String description) {
           this.description = description;    }    @Override    public String toString() {
           return "Book{" +                "id=" + id +                ", name='" + name + '\'' +                ", author='" + author + '\'' +                ", price=" + price +                ", description='" + description + '\'' +                '}';    }}

Service

package pers.zhang.service;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.data.domain.Page;import org.springframework.data.domain.Pageable;import org.springframework.stereotype.Service;import pers.zhang.dao.BookDao;import pers.zhang.entity.Book;import java.util.List;/** * @author zhang * @date 2019/12/18 - 22:18 */@Servicepublic class BookService {
       @Autowired    BookDao bookDao;    public void addBook(Book book){
           bookDao.save(book);    }    public Page
   
     getBooksByPage(Pageable pageable){
           return bookDao.findAll(pageable);    }    public List
    
      getBooksByAuthorStartingWith(String author){
           return bookDao.getBooksByAuthorStartingWith(author);    }    public List
     
       getBooksByPriceGreaterThan(Float price){
           return bookDao.getBooksByPriceGreaterThan(price);    }    public Book getMaxIdBook(){
           return bookDao.getMaxIdBook();    }    public List
      
        getBookByIdAndAuthor(String author, Integer id){
           return bookDao.getBookByIdAndAuthor(author, id);    }    public List
       
         getBooksByIdandName(String name, Integer id){
           return bookDao.getBooksByIdAndName(name, id);    }}
       
      
     
    
   

Controller

package pers.zhang.controller;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.data.domain.Page;import org.springframework.data.domain.PageRequest;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.GetMapping;import pers.zhang.entity.Book;import pers.zhang.service.BookService;import java.util.List;/** * @author zhang * @date 2019/12/18 - 22:25 */@Controllerpublic class BookController {
       @Autowired    BookService bookService;    @GetMapping("/findAll")    public void findAll(){
           PageRequest pageRequest = new PageRequest(2, 3);        Page
   
     page = bookService.getBooksByPage(pageRequest);        System.out.println("总页数：" + page.getTotalPages());        System.out.println("总记录数：" + page.getTotalElements());        System.out.println("查询记录：" + page.getContent());        System.out.println("当前页数：" + (page.getNumber() + 1));        System.out.println("当前页记录数：" + page.getNumberOfElements());        System.out.println("每页记录数：" + page.getSize());    }    @GetMapping("/search")    public void search(){
           List
    
      bs1 = bookService.getBookByIdAndAuthor("鲁迅", 7);        List
     
       bs2 = bookService.getBooksByAuthorStartingWith("吴");        List
      
        bs3 = bookService.getBooksByIdandName("西", 8);        List
       
         bs4 = bookService.getBooksByPriceGreaterThan(30f);        Book b = bookService.getMaxIdBook();        System.out.println("bs1：" + bs1);        System.out.println("bs2:" + bs2);        System.out.println("bs3:" + bs3);        System.out.println("bs4:" + bs4);        System.out.println("b:" + b);    }    @GetMapping("/save")    public void save(){
           Book book = new Book();        book.setAuthor("鲁迅");        book.setName("呐喊");        book.setPrice(23f);        bookService.addBook(book);    }}
       
      
     
    
   

测试

访问前表数据如下

访问http://localhost:8080/findAll

Hibernate: select book0_.id as id1_0_, book0_.author as author2_0_, book0_.book_name as book_nam3_0_, book0_.price as price4_0_ from t_book book0_ limit ?, ?总页数：3总记录数：7查询记录：[Book{id=7, name='故事新编', author='鲁迅', price=22.0, description='null'}]当前页数：3当前页记录数：1每页记录数：3

访问http://localhost:8080/save

Hibernate: insert into t_book (author, book_name, price) values (?, ?, ?)

数据表变为：

访问http://localhost:8080/search

Hibernate: select book0_.id as id1_0_, book0_.author as author2_0_, book0_.book_name as book_nam3_0_, book0_.price as price4_0_ from t_book book0_ where book0_.id>? and book0_.author=?Hibernate: select book0_.id as id1_0_, book0_.author as author2_0_, book0_.book_name as book_nam3_0_, book0_.price as price4_0_ from t_book book0_ where book0_.author like ?Hibernate: select book0_.id as id1_0_, book0_.author as author2_0_, book0_.book_name as book_nam3_0_, book0_.price as price4_0_ from t_book book0_ where book0_.id
   ?Hibernate: select * from t_book where id = (select max(id) from t_book)bs1：[Book{id=8, name='呐喊', author='鲁迅', price=23.0, description='null'}]bs2:[Book{id=3, name='西游记', author='吴承恩', price=29.0, description='null'}]bs3:[Book{id=3, name='西游记', author='吴承恩', price=29.0, description='null'}]bs4:[Book{id=2, name='红楼梦', author='曹雪芹', price=35.0, description='null'}, Book{id=5, name='宋词选注', author='钱钟书', price=33.0, description='null'}]b:Book{id=8, name='呐喊', author='鲁迅', price=23.0, description='null'}

转载地址：http://xzpqb.baihongyu.com/