PagingAndSortingRepository接口访问数据

小鱼儿 2022-05-10 08:10 210阅读 0赞

**PagingAndSortingRepository继承自CrudRepository接口，所以除了拥有CrudRepository的功能之外，还增加了排序和分页查询的功能。**

**创建持久化类**

程序清单：/jpa/src/main/java/com/dwx/bean/Book.java

package com.dwx.bean;
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
    import javax.persistence.Table;
    @Entity
    @Table(name="t_book")
    public class Book {
    	@Id
    	@GeneratedValue(strategy = GenerationType.IDENTITY)
    	private Integer bookId;			//图书编号
    	private String bookName;		//图书名称
    	private String category;		//类别
    	private String author;			//作者
    	private String press;			//出版社
    	private Double price;			//价格
    	public Integer getBookId() {
    		return bookId;
    	}
    	public void setBookId(Integer bookId) {
    		this.bookId = bookId;
    	}
    	public String getBookName() {
    		return bookName;
    	}
    	public void setBookName(String bookName) {
    		this.bookName = bookName;
    	}
    	public String getCategory() {
    		return category;
    	}
    	public void setCategory(String category) {
    		this.category = category;
    	}
    	public String getAuthor() {
    		return author;
    	}
    	public void setAuthor(String author) {
    		this.author = author;
    	}
    	public String getPress() {
    		return press;
    	}
    	public void setPress(String press) {
    		this.press = press;
    	}
    	public Double getPrice() {
    		return price;
    	}
    	public void setPrice(Double price) {
    		this.price = price;
    	}
    }

**定义数据访问接口**

程序清单：/jpa/src/main/java/com/dwx/repository/BookRepository.java

package com.dwx.repository;
    import org.springframework.data.repository.PagingAndSortingRepository;
    import com.dwx.bean.Book;
    public interface BookRepository extends PagingAndSortingRepository<Book, Integer> {
    
    }

**定义业务层类**

程序清单：/jpa/src/main/java/com/dwx/service/BookService.java

package com.dwx.service;
    import javax.annotation.Resource;
    import org.springframework.data.domain.Page;
    import org.springframework.data.domain.Pageable;
    import org.springframework.data.domain.Sort;
    import org.springframework.stereotype.Service;
    import com.dwx.bean.Book;
    import com.dwx.repository.BookRepository;
    @Service
    public class BookService {
    	@Resource
    	private BookRepository bookRepository;
    	
    	public Iterable<Book> findAllSort(Sort sort){
    		return bookRepository.findAll(sort);
    	}
    	
    	public Page<Book> findAll(Pageable page){
    		return bookRepository.findAll(page);
    	}
    }

**定义控制器类**

程序清单：/jpa/src/main/java/com/dwx/controller/BookController.java

package com.dwx.controller;
    import java.util.List;
    import javax.annotation.Resource;
    import org.springframework.data.domain.Page;
    import org.springframework.data.domain.PageRequest;
    import org.springframework.data.domain.Pageable;
    import org.springframework.data.domain.Sort;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import com.dwx.bean.Book;
    import com.dwx.service.BookService;
    @RestController
    public class BookController {
    	@Resource
    	private BookService bookService;
    	
    	@RequestMapping("/sort")
    	public Iterable<Book> sortBook(){
    		Sort sort=new Sort(Sort.Direction.DESC,"bookId");
    		Iterable<Book> bookSort=bookService.findAllSort(sort);
    		return bookSort;
    	}
    	
    	@RequestMapping("/pager")
    	public List<Book> sortPagerBook(int pageIndex){
    		Sort sort=new Sort(Sort.Direction.DESC,"bookId");
    		Pageable page=PageRequest.of(pageIndex-1, 2,sort);
    		Page<Book> bookDatas=bookService.findAll(page);
    		List<Book> books=bookDatas.getContent();
    		return books;
    	}
    }

**测试应用**

启动Spring Boot项目，访问以下地址：[http://localhost:8080/sort][http_localhost_8080_sort]

![70][]

测试分页查询第一页，访问以下地址：[http://localhost:8080/pager?pageIndex=1][http_localhost_8080_pager_pageIndex_1]

![70 1][]

[http_localhost_8080_sort]: http://localhost:8080/sort
[70]: /images/20220510/2598867f54cb4b93ac6ffd3772b9d399.png
[http_localhost_8080_pager_pageIndex_1]: http://localhost:8080/pager?pageIndex=1
[70 1]: /images/20220510/9d2c88fdaa924a1c8caecd2c75bd7521.png