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Spring Data JPA實現(xiàn)排序與分頁查詢超詳細(xì)流程講解

更新時間：2022年10月28日 10:01:32 作者：showswoller

在介紹Spring Data JPA的時候，我們首先認(rèn)識下Hibernate。Hibernate是數(shù)據(jù)訪問解決技術(shù)的絕對霸主，使用O/R映射技術(shù)實現(xiàn)數(shù)據(jù)訪問，O/R映射即將領(lǐng)域模型類和數(shù)據(jù)庫的表進(jìn)行映射，通過程序操作對象而實現(xiàn)表數(shù)據(jù)操作的能力，讓數(shù)據(jù)訪問操作無須關(guān)注數(shù)據(jù)庫相關(guān)的技術(shù)

前言

在實際開發(fā)場景中，排序與分頁查詢是必須的，幸運的是Spring Data JPA充分考慮了排序與分頁查詢的場景，為我們提供Sort類 Page接口 Pageable接口下面通過一個實戰(zhàn)來闡明

1、創(chuàng)建持久化實體類

創(chuàng)建名為com.ch.ch6_4.entity的包并在該包中創(chuàng)建名為Article和Author的持久化實體類

代碼如下

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;
	//標(biāo)題
	@NotEmpty(message = "標(biāo)題不能為空")
    @Size(min = 2, max = 50)
    @Column(nullable = false, length = 50) 
    private String title;
	//文章內(nèi)容
    @Lob  //大對象，映射 為MySQL的Long文本類型
    @Basic(fetch = FetchType.LAZY) 
    @NotEmpty(message = "內(nèi)容不能為空")
    @Size(min = 2)
    @Column(nullable = false) 
    private String content;
    //所屬作者，文章與作者是多對一的關(guān)系
    @ManyToOne(cascade={CascadeType.MERGE,CascadeType.REFRESH},optional=false)
    //可選屬性optional=false,表示author不能為空。刪除文章，不影響用戶
    @JoinColumn(name="id_author_id")//設(shè)置在article表中的關(guān)聯(lián)字段(外鍵)
    @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，作者與文章是一對多的關(guān)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、創(chuàng)建數(shù)據(jù)訪問層

創(chuàng)建名為com.ch.ch6_4repository的包并在該包中創(chuàng)建名為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>{
	/**
	 * 根據(jù)文章標(biāo)題包含的內(nèi)容，查詢作者（關(guān)聯(lián)查詢）
	 * 相當(dāng)于JPQL語句：select a from Author a  inner join  a.articleList t where t.title like %?1%
	 */
	public Author findByArticleList_titleContaining(String title);
	/**
	 * 根據(jù)文章標(biāo)題包含的內(nèi)容，查詢作者（關(guān)聯(lián)查詢）
	 */
	@Query("select a from Author a  inner join  a.articleList t where t.title like %?1%" )
	public Author findAuthorByArticleListtitleContaining(String title);
}

3、創(chuàng)建業(yè)務(wù)層

創(chuàng)建名為com.ch.ch6_4.service的包并在該包中創(chuàng)建名為ArticleAndAuthorService的接口和接口實現(xiàn)類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);
}

接口實現(xiàn)類

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("陳恒1");
		Author a2 = new Author();
		a2.setAname("陳恒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的一對多111");
		at1.setContent("其實一對多映射關(guān)系很常見111。");
		//設(shè)置關(guān)系
		at1.setAuthor(a1);
		Article at2 = new Article();
		at2.setTitle("JPA的一對多222");
		at2.setContent("其實一對多映射關(guān)系很常見222。");
		//設(shè)置關(guān)系
		at2.setAuthor(a1);//文章2與文章1作者相同
		Article at3 = new Article();
		at3.setTitle("JPA的一對多333");
		at3.setContent("其實一對多映射關(guān)系很常見333。");
		//設(shè)置關(guān)系
		at3.setAuthor(a2);
		Article at4 = new Article();
		at4.setTitle("JPA的一對多444");
		at4.setContent("其實一對多映射關(guān)系很常見444。");
		//設(shè)置關(guān)系
		at4.setAuthor(a2);//文章3與文章4作者相同
		ArrayList<Article> allAt = new ArrayList<Article>();
		allAt.add(at1);
		allAt.add(at2);
		allAt.add(at3);
		allAt.add(at4);
	public Author findByArticleList_titleContaining(String title) {
		return authorRepository.findByArticleList_titleContaining(title);
	}
	@Override
	public Author findAuthorByArticleListtitleContaining(String title) {
		return authorRepository.findAuthorByArticleListtitleContaining(title);
	}
}

4、創(chuàng)建控制器類

創(chuàng)建名為com.ch,ch6_4.controller的包并在該包中創(chuàng)建名為TestSortAndPage的控制器類

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第幾頁
	 */
	public String findAllAuthorByPage(Integer page, Model model){
		return articleAndAuthorService.findAllAuthorByPage(page, model);
	}
}

5、創(chuàng)建View視圖頁面

創(chuàng)建index.html頁面部分代碼如下

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>顯示分頁查詢結(jié)果</title>
<link rel="stylesheet" th:href="@{css/bootstrap.min.css}" rel="external nofollow"  />
<link rel="stylesheet" th:href="@{css/bootstrap-theme.min.css}" rel="external nofollow"  />
</head>
<body>
	<div class="panel panel-primary">
		<div class="panel-heading">
			<h3 class="panel-title">Spring Data JPA分頁查詢</h3>
		</div>
							</tr>
							<tr>
							<td colspan="2" align="right">
								<ul class="pagination">
									<li><a>第<span th:text="${page}"></span>頁</a></li>
									<li><a>共<span th:text="${totalPage}"></span>頁</a></li>
									<li><a>共<span th:text="${totalCount}"></span>條</a></li>
									<li>
									<a th:href="@{findAllAuthorByPage(page=${page-1})}" rel="external nofollow"  th:if="${page != 1}">上一頁</a>
									</li>
									<li><a th:href="@{findAllAuthorByPage(page=${page+1})}" rel="external nofollow"  th:if="${page != totalPage}">下一頁</a>
									</li>
								</ul>
							</td>
						</tr>
						</tbody>
					</table>
				</div>
			</div>
		</div>
	</div>
</body>
</html>

6、運行主類效果如下

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