Spring Boot利用Spring Data JPA实现排序与分页查询实战(附源码，超详细）

ゝ一纸荒年。 2023-09-30 16:12 12阅读 0赞

**在实际开发场景中，排序与分页查询是必须的，幸运的是Spring Data JPA充分考虑了排序与分页查询的场景，为我们提供Sort类 Page接口 Pageable接口 下面通过一个实战来阐明**

## 1：创建持久化实体类 ##

创建名为com.ch.ch6\_4.entity的包 并在该包中创建名为Article和Author的持久化实体类

代码如下

Article

package com.ch.ch6_2.entity;
    import java.io.Serializable;
    import javax.persistence.Basic;
    import javax.persistence.CascadeType;
    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.FetchType;
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
    import javax.persistence.JoinColumn;
    import javax.persistence.Lob;
    import javax.persistence.ManyToOne;
    import javax.persistence.Table;
    import javax.validation.constraints.NotEmpty;
    import javax.validation.constraints.Size;
    import com.fasterxml.jackson.annotation.JsonIgnore;
    import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
    @Entity
    @Table(name = "article_table")
    @JsonIgnoreProperties(value = { "hibernateLazyInitializer"})
    public class Article  implements Serializable{
    	private static final long serialVersionUID = 1L;
    	@Id
    	@GeneratedValue(strategy = GenerationType.IDENTITY)
    	private int id;
    	//标题
    	@NotEmpty(message = "标题不能为空")
        @Size(min = 2, max = 50)
        @Column(nullable = false, length = 50) 
        private String title;
    	//文章内容
        @Lob  //大对象，映射 为MySQL的Long文本类型
        @Basic(fetch = FetchType.LAZY) 
        @NotEmpty(message = "内容不能为空")
        @Size(min = 2)
        @Column(nullable = false) 
        private String content;
        //所属作者，文章与作者是多对一的关系
        @ManyToOne(cascade={CascadeType.MERGE,CascadeType.REFRESH},optional=false)
        //可选属性optional=false,表示author不能为空。删除文章，不影响用户
        @JoinColumn(name="id_author_id")//设置在article表中的关联字段(外键)
        @JsonIgnore
        private Author author;
    	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 getContent() {
    		return content;
    	}
    	public void setContent(String content) {
    		this.content = content;
    	}
    	public Author getAuthor() {
    		return author;
    	}
    	public void setAuthor(Author author) {
    		this.author = author;
    	}
    }

Author

package com.ch.ch6_2.entity;
    import java.io.Serializable;
    import java.util.List;
    import javax.persistence.CascadeType;
    import javax.persistence.Entity;
    import javax.persistence.FetchType;
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
    import javax.persistence.OneToMany;
    import javax.persistence.Table;
    import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
    @Entity
    @Table(name = "author_table")
    @JsonIgnoreProperties(value = { "hibernateLazyInitializer"})
    public class Author implements Serializable{
    	private static final long serialVersionUID = 1L;
    	@Id
    	@GeneratedValue(strategy = GenerationType.IDENTITY)
    	private int id;
    	//作者名
    	private String aname;
    	//文章列表，作者与文章是一对多的关系
        @OneToMany(
        		mappedBy = "author",
        		cascade=CascadeType.ALL,
        		targetEntity = Article.class, 
        		fetch=FetchType.LAZY
        		)
        private List<Article> articleList;
    	public int getId() {
    		return id;
    	}
    	public void setId(int id) {
    		this.id = id;
    	}
    	public String getAname() {
    		return aname;
    	}
    	public void setAname(String aname) {
    		this.aname = aname;
    	}
    	public List<Article> getArticleList() {
    		return articleList;
    	}
    	public void setArticleList(List<Article> articleList) {
    		this.articleList = articleList;
    	}
    }

## 2：创建数据访问层 ##

创建名为com.ch.ch6\_4repository的包 并在该包中创建名为AuthorRepository的接口

package com.ch.ch6_2.repository;
    import org.springframework.data.jpa.repository.JpaRepository;
    import org.springframework.data.jpa.repository.Query;
    
    import com.ch.ch6_2.entity.Author;
    public interface AuthorRepository extends JpaRepository<Author, Integer>{
    	/**
    	 * 根据文章标题包含的内容，查询作者（关联查询）
    	 * 相当于JPQL语句：select a from Author a  inner join  a.articleList t where t.title like %?1%
    	 */
    	public Author findByArticleList_titleContaining(String title);
    	/**
    	 * 根据文章标题包含的内容，查询作者（关联查询）
    	 */
    	@Query("select a from Author a  inner join  a.articleList t where t.title like %?1%" )
    	public Author findAuthorByArticleListtitleContaining(String title);
    }

## 3：创建业务层 ##

创建名为com.ch.ch6\_4.service的包 并在该包中创建名为ArticleAndAuthorService的接口和接口实现类ArticleAndAuthorServiceImpl

接口

package com.ch.ch6_2.service;
    import java.util.List;
    import com.ch.ch6_2.entity.Article;
    import com.ch.ch6_2.entity.Author;
    public interface AuthorAndArticleService {
    	public void saveAll();
    	public List<Article> findByAuthor_id(Integer id);
    	public List<Article> findByAuthor_aname(String aname);
    	public Author findByArticleList_titleContaining(String title);
    	public Author findAuthorByArticleListtitleContaining(String title);
    }

接口实现类

package com.ch.ch6_2.service;
    import java.util.ArrayList;
    import java.util.List;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    import com.ch.ch6_2.entity.Article;
    import com.ch.ch6_2.entity.Author;
    import com.ch.ch6_2.repository.ArticleRepository;
    import com.ch.ch6_2.repository.AuthorRepository;
    @Service
    public class AuthorAndArticleServiceImpl implements AuthorAndArticleService{
    	@Autowired
    	private AuthorRepository authorRepository;
    	@Autowired
    	private ArticleRepository articleRepository;
    	@Override
    	public void saveAll() {
    		//保存作者（先保存一的一端）
    		Author a1 = new Author();
    		a1.setAname("陈恒1");
    		Author a2 = new Author();
    		a2.setAname("陈恒2");
    		ArrayList<Author> allAuthor = new ArrayList<Author>();
    		allAuthor.add(a1);
    		allAuthor.add(a2);
    		authorRepository.saveAll(allAuthor);
    		//保存文章
    		Article at1 = new Article();
    		at1.setTitle("JPA的一对多111");
    		at1.setContent("其实一对多映射关系很常见111。");
    		//设置关系
    		at1.setAuthor(a1);
    		Article at2 = new Article();
    		at2.setTitle("JPA的一对多222");
    		at2.setContent("其实一对多映射关系很常见222。");
    		//设置关系
    		at2.setAuthor(a1);//文章2与文章1作者相同
    		Article at3 = new Article();
    		at3.setTitle("JPA的一对多333");
    		at3.setContent("其实一对多映射关系很常见333。");
    		//设置关系
    		at3.setAuthor(a2);
    		Article at4 = new Article();
    		at4.setTitle("JPA的一对多444");
    		at4.setContent("其实一对多映射关系很常见444。");
    		//设置关系
    		at4.setAuthor(a2);//文章3与文章4作者相同
    		ArrayList<Article> allAt = new ArrayList<Article>();
    		allAt.add(at1);
    		allAt.add(at2);
    		allAt.add(at3);
    		allAt.add(at4);
    		a
    	public Author findByArticleList_titleContaining(String title) {
    		return authorRepository.findByArticleList_titleContaining(title);
    	}
    	@Override
    	public Author findAuthorByArticleListtitleContaining(String title) {
    		return authorRepository.findAuthorByArticleListtitleContaining(title);
    	}
    	
    
    }

## 4：创建控制器类 ##

创建名为com.ch,ch6\_4.controller的包 并在该包中创建名为TestSortAndPage的控制器类

package com.ch.ch6_4.controller;
    import java.util.List;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.Model;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;
    import com.ch.ch6_4.entity.Author;
    import com.ch.ch6_4.service.ArticleAndAuthorService;
    @Controller
    public class TestSortAndPage {
    	@Autowired 
    	private ArticleAndAuthorService articleAndAuthorService;
    	@RequestMapping("/findByAnameContaining")
    	@ResponseBody
    	public List<Author> findByAnameContaining(String aname, String sortColum){
    		return articleAndAuthorService.findByAnameContaining(aname, sortColum);
    	}
    	@RequestMapping("/findAllAuthorByPage")
    	/**
    	 * @param page第几页
    	 */
    	public String findAllAuthorByPage(Integer page, Model model){
    		return articleAndAuthorService.findAllAuthorByPage(page, model);
    	}
    }

## 5：创建View视图页面 ##

创建index.html页面 部分代码如下

<!DOCTYPE html>
    <html xmlns:th="http://www.thymeleaf.org">
    <head>
    <meta charset="UTF-8">
    <title>显示分页查询结果</title>
    <link rel="stylesheet" th:href="@{css/bootstrap.min.css}" />
    <link rel="stylesheet" th:href="@{css/bootstrap-theme.min.css}" />
    </head>
    <body>
    	<div class="panel panel-primary">
    		<div class="panel-heading">
    			<h3 class="panel-title">Spring Data JPA分页查询</h3>
    		</div>
    
    							</tr>
    							<tr>
    							<td colspan="2" align="right">
    								<ul class="pagination">
    									<li><a>第<span th:text="${page}"></span>页</a></li>
    									<li><a>共<span th:text="${totalPage}"></span>页</a></li>
    									<li><a>共<span th:text="${totalCount}"></span>条</a></li>
    									<li>
    									<a th:href="@{findAllAuthorByPage(page=${page-1})}" th:if="${page != 1}">上一页</a>
    									</li>
    									<li><a th:href="@{findAllAuthorByPage(page=${page+1})}" th:if="${page != totalPage}">下一页</a>
    									</li>
    								</ul>
    							</td>
    						</tr>
    						</tbody>
    					</table>
    				</div>
    			</div>
    		</div>
    	</div>
    </body>
    </html>

## 6：运行主类 效果如下 ##

![4a72ef60e30948938cd827f7ab237ae6.png][]

[4a72ef60e30948938cd827f7ab237ae6.png]: https://img-blog.csdnimg.cn/4a72ef60e30948938cd827f7ab237ae6.png