在Spring Boot中使用Spring-data-jpa實現分頁查詢（轉）

時間  2019-11-30
標籤 spring boot 使用 data jpa 實現 分頁 查詢 欄目 Spring 简体版
原文   原文鏈接

在咱們平時的工做中，查詢列表在咱們的系統中基本隨處可見，那麼咱們如何使用jpa進行多條件查詢以及查詢列表分頁呢？下面我將介紹兩種多條件查詢方式。javascript

一、引入起步依賴  css

  
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

 

二、對thymeleaf和jpa進行配置
打開application.yml，添加如下參數，如下配置在以前的文章中介紹過，此處不作過多說明html

spring:
  thymeleaf:
    cache: true
    check-template-location: true
    content-type: text/html
    enabled: true
    encoding: utf-8
    mode: HTML5
    prefix: classpath:/templates/
    suffix: .html
    excluded-view-names:
    template-resolver-order:
  datasource:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://localhost:3306/restful?useUnicode=true&characterEncoding=UTF-8&useSSL=false
      username: root
      password: root
      initialize: true
  init-db: true
  jpa:
      database: mysql
      show-sql: true
      hibernate:
        ddl-auto: update
        naming:
          strategy: org.hibernate.cfg.ImprovedNamingStrategy

 

三、編寫實體Beanjava

  
@Entity
@Table(name="book")
public class Book {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", updatable = false)
    private Long id;

    @Column(nullable = false,name = "name")
    private String name;

    @Column(nullable = false,name = "isbn")
    private String isbn;

    @Column(nullable = false,name = "author")
    private String author;

    public Book (String name,String isbn,String author){
        this.name = name;
        this.isbn = isbn;
        this.author = author;
    }
    public Book(){

    }
    //此處省去get、set方法
}

public class BookQuery {
    private String name;
    private String isbn;
    private String author;
    //此處省去get、set方法
}

　　

四、編寫Repository接口mysql

@Repository("bookRepository")
public interface BookRepository extends JpaRepository<Book,Long>
        ,JpaSpecificationExecutor<Book> {
}

　　 

此處繼承了兩個接口，後續會介紹爲什麼會繼承這兩個接口

 

五、抽象service層
首先抽象出接口jquery

  
public interface BookQueryService {
    Page<Book> findBookNoCriteria(Integer page,Integer size);
    Page<Book> findBookCriteria(Integer page,Integer size,BookQuery bookQuery);
}

　　

實現接口web

  
@Service(value="https://my.oschina.net/wangxincj/blog/bookQueryService")
public class BookQueryServiceImpl implements BookQueryService {
    @Resource
    BookRepository bookRepository;
    @Override
    public Page<Book> findBookNoCriteria(Integer page,Integer size) {
        Pageable pageable = new PageRequest(page, size, Sort.Direction.ASC, "id");
        return bookRepository.findAll(pageable);
    }

    @Override
    public Page<Book> findBookCriteria(Integer page, Integer size, final BookQuery bookQuery) {
        Pageable pageable = new PageRequest(page, size, Sort.Direction.ASC, "id");
        Page<Book> bookPage = bookRepository.findAll(new Specification<Book>(){
            @Override
            public Predicate toPredicate(Root<Book> root, CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
                List<Predicate> list = new ArrayList<Predicate>();
                if(null!=bookQuery.getName()&&!"".equals(bookQuery.getName())){
                    list.add(criteriaBuilder.equal(root.get("name").as(String.class), bookQuery.getName()));
                }
                if(null!=bookQuery.getIsbn()&&!"".equals(bookQuery.getIsbn())){
                    list.add(criteriaBuilder.equal(root.get("isbn").as(String.class), bookQuery.getIsbn()));
                }
                if(null!=bookQuery.getAuthor()&&!"".equals(bookQuery.getAuthor())){
                    list.add(criteriaBuilder.equal(root.get("author").as(String.class), bookQuery.getAuthor()));
                }
                Predicate[] p = new Predicate[list.size()];
                return criteriaBuilder.and(list.toArray(p));
            }
        },pageable);
        return bookPage;
    }
}

　　

    此處我定義了兩個接口，findBookNoCriteria是不帶查詢條件的，findBookCriteria是帶查詢條件的。在此處介紹一下上面提到的自定義Repository繼承的兩個接口，若是你的查詢列表是沒有查詢條件，只是列表展現和分頁，只需繼承JpaRepository接口便可，可是若是你的查詢列表是帶有多個查詢條件的話則須要繼承JpaSpecificationExecutor接口，這個接口裏面定義的多條件查詢的方法。固然無論繼承哪一個接口，當你作分頁查詢時，都是須要調用findAll方法的，這個方法是jap定義好的分頁查詢方法。

findBookCriteria方法也可使用如下方法實現，你們能夠自行選擇spring

  
@Override
    public Page<Book> findBookCriteria(Integer page, Integer size, final BookQuery bookQuery) {
        Pageable pageable = new PageRequest(page, size, Sort.Direction.ASC, "id");
        Page<Book> bookPage = bookRepository.findAll(new Specification<Book>(){
            @Override
            public Predicate toPredicate(Root<Book> root, CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
                Predicate p1 = criteriaBuilder.equal(root.get("name").as(String.class), bookQuery.getName());
                Predicate p2 = criteriaBuilder.equal(root.get("isbn").as(String.class), bookQuery.getIsbn());
                Predicate p3 = criteriaBuilder.equal(root.get("author").as(String.class), bookQuery.getAuthor());
                query.where(criteriaBuilder.and(p1,p2,p3));
                return query.getRestriction();
            }
        },pageable);
        return bookPage;
    }

　　

六、編寫Controller
針對有查詢條件和無查詢條件，咱們分別編寫一個Controller，默認每頁顯示5條，以下sql

  
@Controller
@RequestMapping(value = "https://my.oschina.net/queryBook")
public class BookController {
    @Autowired
    BookQueryService bookQueryService;

    @RequestMapping("/findBookNoQuery")
    public String findBookNoQuery(ModelMap modelMap,@RequestParam(value = "https://my.oschina.net/wangxincj/blog/page", defaultValue = "https://my.oschina.net/wangxincj/blog/0") Integer page,
                        @RequestParam(value = "https://my.oschina.net/wangxincj/blog/size", defaultValue = "https://my.oschina.net/wangxincj/blog/5") Integer size){
        Page<Book> datas = bookQueryService.findBookNoCriteria(page, size);
        modelMap.addAttribute("datas", datas);
        return "index1";
    }

    @RequestMapping(value = "https://my.oschina.net/findBookQuery",method = {RequestMethod.GET,RequestMethod.POST})
    public String findBookQuery(ModelMap modelMap, @RequestParam(value = "https://my.oschina.net/wangxincj/blog/page", defaultValue = "https://my.oschina.net/wangxincj/blog/0") Integer page,
                                @RequestParam(value = "https://my.oschina.net/wangxincj/blog/size", defaultValue = "https://my.oschina.net/wangxincj/blog/5") Integer size, BookQuery bookQuery){
        Page<Book> datas = bookQueryService.findBookCriteria(page, size,bookQuery);
        modelMap.addAttribute("datas", datas);
        return "index2";
    }
}

　　

七、編寫頁面
首先咱們編寫一個通用的分頁頁面，新建一個叫page.html的頁面數據庫

  
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:th="http://www.thymeleaf.org"
      xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout"
      layout:decorator="page">
<body>
<div th:fragment="pager">
    <div class="text-right" th:with="baseUrl=${#httpServletRequest.getRequestURL().toString()},pars=${#httpServletRequest.getQueryString() eq null ? '' : new String(#httpServletRequest.getQueryString().getBytes('iso8859-1'), 'UTF-8')}">
        <ul style="margin:0px;" class="pagination" th:with="newPar=${new Java.lang.String(pars eq null ? '' : pars).replace('page='+(datas.number), '')},
                                                curTmpUrl=${baseUrl+'?'+newPar},
                                                curUrl=${curTmpUrl.endsWith('&') ? curTmpUrl.substring(0, curTmpUrl.length()-1):curTmpUrl}" >
            <!--<li th:text="${pars}"></li>-->

            <li><a href="https://my.oschina.net/wangxincj/blog/#" th:href="https://my.oschina.net/wangxincj/blog/@{${curUrl}(page=0)}">首頁</a></li>
            <li th:if="${datas.hasPrevious()}"><a href="https://my.oschina.net/wangxincj/blog/#" th:href="https://my.oschina.net/wangxincj/blog/@{${curUrl}(page=${datas.number-1})}">上一頁</a></li>

            <!--總頁數小於等於10-->
            <div th:if="${(datas.totalPages le 10) and (datas.totalPages gt 0)}" th:remove="tag">
                <div th:each="pg : ${#numbers.sequence(0, datas.totalPages - 1)}" th:remove="tag">
                        <span th:if="${pg eq datas.getNumber()}" th:remove="tag">
                            <li class="active"><span class="current_page line_height" th:text="${pg+1}">${pageNumber}</span></li>
                        </span>
                    <span th:unless="${pg eq datas.getNumber()}" th:remove="tag">
                            <li><a href="https://my.oschina.net/wangxincj/blog/#" th:href="https://my.oschina.net/wangxincj/blog/@{${curUrl}(page=${pg})}" th:text="${pg+1}"></a></li>
                        </span>
                </div>
            </div>

            <!-- 總數數大於10時 -->
            <div th:if="${datas.totalPages gt 10}" th:remove="tag">
                <li th:if="${datas.number-2 ge 0}"><a href="https://my.oschina.net/wangxincj/blog/#" th:href="https://my.oschina.net/wangxincj/blog/@{${curUrl}(page=${datas.number}-2)}" th:text="${datas.number-1}"></a></li>
                <li th:if="${datas.number-1 ge 0}"><a href="https://my.oschina.net/wangxincj/blog/#" th:href="https://my.oschina.net/wangxincj/blog/@{${curUrl}(page=${datas.number}-1)}" th:text="${datas.number}"></a></li>
                <li class="active"><span class="current_page line_height" th:text="${datas.number+1}"></span></li>
                <li th:if="${datas.number+1 lt datas.totalPages}"><a href="https://my.oschina.net/wangxincj/blog/#" th:href="https://my.oschina.net/wangxincj/blog/@{${curUrl}(page=${datas.number}+1)}" th:text="${datas.number+2}"></a></li>
                <li th:if="${datas.number+2 lt datas.totalPages}"><a href="https://my.oschina.net/wangxincj/blog/#" th:href="https://my.oschina.net/wangxincj/blog/@{${curUrl}(page=${datas.number}+2)}" th:text="${datas.number+3}"></a></li>
            </div>


            <li th:if="${datas.hasNext()}"><a href="https://my.oschina.net/wangxincj/blog/#" th:href="https://my.oschina.net/wangxincj/blog/@{${curUrl}(page=${datas.number+1})}">下一頁</a></li>
            <!--<li><a href="https://my.oschina.net/wangxincj/blog/#" th:href="https://my.oschina.net/wangxincj/blog/@{${curUrl}(page=${datas.totalPages-1})}">尾頁</a></li>-->
            <li><a href="https://my.oschina.net/wangxincj/blog/#" th:href="https://my.oschina.net/wangxincj/blog/${datas.totalPages le 0 ? curUrl+'page=0':curUrl+'&page='+(datas.totalPages-1)}">尾頁</a></li>
            <li><span th:utext="'共'+${datas.totalPages}+'頁 / '+${datas.totalElements}+' 條'"></span></li>
        </ul>
    </div>
</div>
</body>
</html>

　　

針對無查詢條件的接口，建立一個名爲index1.html的頁面並引入以前寫好的分頁頁面，以下

  
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="UTF-8"/>
    <title>Title</title>
    <script type="text/javascript" th:src="https://my.oschina.net/wangxincj/blog/@{/jquery-1.12.3.min.js}"></script>
    <script type="text/javascript" th:src="https://my.oschina.net/wangxincj/blog/@{/bootstrap/js/bootstrap.min.js}"></script>
    <link type="text/css" rel="stylesheet" th:href="https://my.oschina.net/wangxincj/blog/@{/bootstrap/css/bootstrap-theme.min.css}"/>
    <link type="text/css" rel="stylesheet" th:href="https://my.oschina.net/wangxincj/blog/@{/bootstrap/css/bootstrap.css}"/>
</head>
<body>
    <table class="table table-hover">
        <thead>
        <tr>
            <th>ID</th>
            <th>name</th>
            <th>isbn</th>
            <th>author</th>
        </tr>
        </thead>
        <tbody>
        <tr th:each="obj : ${datas}">
            <td th:text="${obj.id}">${obj.id}</td>
            <td th:text="${obj.name}">${obj.name}</td>
            <td th:text="${obj.isbn}">${obj.isbn}</td>
            <td th:text="${obj.name}">${obj.author}</td>
        </tr>
        </tbody>
    </table>
        <div th:include="page :: pager" th:remove="tag"></div>
</body>
</html>

　　

針對有查詢條件的接口，建立一個名爲index2.html的頁面並引入以前寫好的分頁頁面，以下 <!DOCTYPE html> <html lang="en" xmlns:th="http://www.w3.org/1999/xhtml"> <head> <meta charset="UTF-8"/> <title>Title</title> <script type="text/javascript" th:src="https://my.oschina.net/wangxincj/blog/@{/jquery-1.12.3.min.js}"></script> <script type="text/javascript" th:src="https://my.oschina.net/wangxincj/blog/@{/bootstrap/js/bootstrap.min.js}"></script> <link type="text/css" rel="stylesheet" th:href="https://my.oschina.net/wangxincj/blog/@{/bootstrap/css/bootstrap-theme.min.css}"/> <link type="text/css" rel="stylesheet" th:href="https://my.oschina.net/wangxincj/blog/@{/bootstrap/css/bootstrap.css}"/> </head> <body> <form th:action="@{/queryBook/findBookQuery}" th:object="${bookQuery}" th:method="get"> <div class="form-group"> <label class="col-sm-2 control-label" >name</label> <div class="col-sm-4"> <input type="text" class="form-control" id="name" placeholder="請輸入名稱" th:field="*{name}"/> </div> <label class="col-sm-2 control-label">isbn</label> <div class="col-sm-4"> <input type="text" class="form-control" id="isbn" placeholder="請輸ISBN" th:field="*{isbn}"/> </div> </div> <div class="form-group"> <label class="col-sm-2 control-label" >author</label> <div class="col-sm-4"> <input type="text" class="form-control" id="author" placeholder="請輸author" th:field="*{author}"/> </div> <div class="col-sm-4"> <button class="btn btn-default" type="submit" placeholder="查詢">查詢</button> </div> </div> </form> <table class="table table-hover"> <thead> <tr> <th>ID</th> <th>name</th> <th>isbn</th> <th>author</th> </tr> </thead> <tbody> <tr th:each="obj : ${datas}"> <td th:text="${obj.id}">${obj.id}</td> <td th:text="${obj.name}">${obj.name}</td> <td th:text="${obj.isbn}">${obj.isbn}</td> <td th:text="${obj.name}">${obj.author}</td> </tr> </tbody> </table> <div th:include="page :: pager" th:remove="tag"></div> </body> </html>

 

ok！代碼都已經完成，咱們將項目啓動起來，看一下效果。你們能夠往數據庫中批量插入一些數據，訪問http://localhost:8080/queryBook/findBookNoQuery，顯示以下頁面

訪問http://localhost:8080/queryBook/findBookQuery，顯示頁面以下，能夠輸入查詢條件進行帶條件的分頁查詢：

ok！以上即是一個簡單的jap分頁查詢功能的實現。

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