SpringData核心数据访问接口--PagingAndSortingRepository

逃离我推掉我的手 2023-10-17 22:37 4阅读 0赞

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

创建一个Maven项目，在src/main下新建一个名为resources的文件夹。

①**修改pom.xml**

<groupId>com.ysh</groupId>  
<artifactId>pagingandsortingrepositorytest</artifactId>  
<version>0.0.1-SNAPSHOT</version>  
<packaging>jar</packaging>

<name>pagingandsortingrepositorytest</name>  
<url>http://maven.apache.org</url>

<parent>  
<groupId>org.springframework.boot</groupId>  
<artifactId>spring-boot-starter-parent</artifactId>  
<version>2.0.0.RELEASE</version>  
<relativePath/>  
</parent>  
  
<properties>  
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>  
<java.version>1.8</java.version>  
</properties>

<dependencies>  
  
  
<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>mysql</groupId>  
<artifactId>mysql-connector-java</artifactId>  
</dependency>  
  
  
<dependency>  
<groupId>org.springframework.boot</groupId>  
<artifactId>spring-boot-starter-data-jpa</artifactId>  
</dependency>  
  
<dependency>  
<groupId>junit</groupId>  
<artifactId>junit</artifactId>  
<scope>test</scope>  
</dependency>  
</dependencies>  
</project>

修改完之后，保存，右击项目名选择Maven---update project

②**配置基本属性**

在src/main/resources下新建一个全局配置文件，命名为application.properties

\#数据库地址，其中springdatajpa是数据库名称

spring.datasource.url=jdbc:mysql://localhost:3306/springdatajpa

\#数据库用户名

spring.datasource.username=root

\#数据库密码，要改成自己的密码

spring.datasource.password=yourpassword

\#数据库驱动，固定格式

spring.datasource.driverClassName=com.mysql.jdbc.Driver

\#指定连接池中最大的活跃连接数

spring.datasource.max-active=20

\#指定连接池最大的空闲连接

spring.datasource.max-idle=8

\#指定必须保持连接的最小值

spring.datasource.min-idle=8

spring.datasource.initial-size=10

\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\#\#\# JPA持久化配置  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
\# 指定数据库类型  
spring.jpa.database=MySQL  
\# 指定是否需要在日志中显示sql语句  
spring.jpa.show-sql=true  
\# 指定自动创建|更新|验证数据库表结构等配置  
\# 表示如果数据库中存在持久化类对应的表就不创建，不存在就创建对应的表  
spring.jpa.hibernate.ddl-auto=update  
\# 指定命名策略  
spring.jpa.hibernate.naming-strategy=org.hibernate.cfg.ImprovedNamingStrategy  
\#指定数据库方言  
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect

③**创建持久化类**

在com.ysh下新建4个包，bean(放置持久化类)、controller(控制器)、repository(定义数据访问接口的类)、service(业务逻辑处理类)

在bean下创建持久化类Article.java

package com.ysh.pagingandsortingrepositorytest.bean;

import java.io.Serializable;  
import java.util.Date;

import javax.persistence.Entity;  
import javax.persistence.GeneratedValue;  
import javax.persistence.GenerationType;  
import javax.persistence.Id;  
import javax.persistence.Table;

/\*\*  
\* 商品对象  
\* \*/  
@Entity  
@Table(name="tb\_article")  
public class Article implements Serializable\{

private static final long serialVersionUID = 1L;  
  
@Id  
@GeneratedValue(strategy = GenerationType.IDENTITY)  
private int id;  
private String title;  
private String supplier;  
private Double price;  
private String locality;  
private Date putawayDate;  
private int storage;  
private String image;  
private String description;  
private Date createDate;  
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 getSupplier() \{  
return supplier;  
\}  
public void setSupplier(String supplier) \{  
this.supplier = supplier;  
\}  
public Double getPrice() \{  
return price;  
\}  
public void setPrice(Double price) \{  
this.price = price;  
\}  
public String getLocality() \{  
return locality;  
\}  
public void setLocality(String locality) \{  
this.locality = locality;  
\}  
public Date getPutawayDate() \{  
return putawayDate;  
\}  
public void setPutawayDate(Date putawayDate) \{  
this.putawayDate = putawayDate;  
\}  
public int getStorage() \{  
return storage;  
\}  
public void setStorage(int storage) \{  
this.storage = storage;  
\}  
public String getImage() \{  
return image;  
\}  
public void setImage(String image) \{  
this.image = image;  
\}  
public String getDescription() \{  
return description;  
\}  
public void setDescription(String description) \{  
this.description = description;  
\}  
public Date getCreateDate() \{  
return createDate;  
\}  
public void setCreateDate(Date createDate) \{  
this.createDate = createDate;  
\}

④**定义数据访问层接口**

在repository包下新建一个接口，命名为ArticleRepository,让该接口继承PagingAndSortingRepository

package com.ysh.pagingandsortingrepositorytest.repository;

import org.springframework.data.repository.PagingAndSortingRepository;

import com.ysh.pagingandsortingrepositorytest.bean.Article;

public interface ArticleRepository extends PagingAndSortingRepository<Article, Integer> \{

在Spring Boot项目中，数据访问层接口无须提供实现，直接继承数据访问接口即可

⑤定义业务层类

ArticleService.java

package com.ysh.pagingandsortingrepositorytest.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.ysh.pagingandsortingrepositorytest.bean.Article;  
import com.ysh.pagingandsortingrepositorytest.repository.ArticleRepository;

@Service  
public class ArticleService \{  
  
// 注入数据访问层接口对象  
@Resource  
private ArticleRepository articleRepository;  
  
public Iterable<Article> findAllSort(Sort sort) \{  
return articleRepository.findAll(sort);  
\}

public Page<Article> findAll(Pageable page) \{  
return articleRepository.findAll(page);  
\}

⑥**定义控制器类**

在controller包下先新建一个控制器类，命名ArticleController

package com.ysh.pagingandsortingrepositorytest.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.ysh.pagingandsortingrepositorytest.bean.Article;  
import com.ysh.pagingandsortingrepositorytest.service.ArticleService;

@RestController  
@RequestMapping("/article")  
public class ArticleController \{  
  
// 注入ArticleService  
@Resource  
private ArticleService articleService;

@RequestMapping("/sort")  
public Iterable<Article> sortArticle() \{  
// 指定排序参数对象：根据id，进行降序查询  
Sort sort = new Sort(Sort.Direction.DESC, "id");  
Iterable<Article> articleDatas = articleService.findAllSort(sort);  
return articleDatas;  
\}

@RequestMapping("/pager")  
public List<Article> sortPagerArticle(int pageIndex) \{  
// 指定排序参数对象：根据id，进行降序查询  
Sort sort = new Sort(Sort.Direction.DESC, "id");  
/\*\*  
\* 封装分页实体 参数一：pageIndex表示当前查询的第几页(默认从0开始，0表示第一页) 参数二：表示每页展示多少数据，现在设置每页展示2条数据  
\* 参数三：封装排序对象，根据该对象的参数指定根据id降序查询  
\* \*/  
Pageable page = PageRequest.of(pageIndex - 1, 2, sort);  
Page<Article> articleDatas = articleService.findAll(page);  
System.out.println("查询总页数:" + articleDatas.getTotalPages());  
System.out.println("查询总记录数:" + articleDatas.getTotalElements());  
System.out.println("查询当前第几页:" + articleDatas.getNumber() + 1);  
System.out.println("查询当前页面的记录数:" + articleDatas.getNumberOfElements());  
// 查询出的结果数据集合  
List<Article> articles = articleDatas.getContent();  
System.out.println("查询当前页面的集合:" + articles);  
return articles;  
\}  
\}

⑦**测试应用**

启动MySql数据库，新建数据库springdatajpa数据库

新建App.java启动类

package com.ysh.pagingandsortingrepositorytest;

import org.springframework.boot.SpringApplication;  
import org.springframework.boot.autoconfigure.SpringBootApplication;

/\*\*  
\* @SpringBootApplication指定这是一个 spring boot的应用程序.  
\*/  
@SpringBootApplication  
public class App  
\{  
public static void main( String\[\] args )  
\{  
// SpringApplication 用于从main方法启动Spring应用的类。  
SpringApplication.run(App.class, args);  
\}  
\}

项目启动后，JPA会在数据库中自动创建持久化类对应的tb\_article表，然后打开此表，插入一些数据

![70][]

打开浏览器，输入:localhost:8080/article/sort

请求会提交到ArticleController类的sortArticle方法进行处理，该方法执行顺序查询，将tb\_article表中的数据以降序的方式查出并以JSON格式返回浏览器

**用谷歌浏览器打开：**

![70 1][]

**用火狐浏览器打开：**

![70 2][]

测试分页查询第一页商品数据，在浏览器中输入：[http://localhost:8080/article/pager?pageIndex=1][http_localhost_8080_article_pager_pageIndex_1]

请求会提交到ArticleController类的sortPageArticle方法中进行处理，该方法接受pageIndex参数，根据参数确定查询第几页数据

查询第一页数据

![70 3][]

查询第二页数据：在浏览器中输入：[http://localhost:8080/article/pager?pageIndex=][http_localhost_8080_article_pager_pageIndex_1]2

![70 4][]

附：项目目录结构

![70 5][]

示例代码下载：

[https://download.csdn.net/download/badao\_liumang\_qizhi/10549085][https_download.csdn.net_download_badao_liumang_qizhi_10549085]

[http_maven.apache.org_POM_4.0.0]: http://maven.apache.org/POM/4.0.0
[http_www.w3.org_2001_XMLSchema-instance]: http://www.w3.org/2001/XMLSchema-instance
[http_maven.apache.org_xsd_maven-4.0.0.xsd]: http://maven.apache.org/xsd/maven-4.0.0.xsd
[70]: https://img-blog.csdn.net/20180718161422249?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 1]: https://img-blog.csdn.net/20180718161437947?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 2]: https://img-blog.csdn.net/20180718161453533?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[http_localhost_8080_article_pager_pageIndex_1]: http://localhost:8080/article/pager?pageIndex=1
[70 3]: https://img-blog.csdn.net/20180718161508497?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 4]: https://img-blog.csdn.net/20180718161524651?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 5]: https://img-blog.csdn.net/20180718161620168?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[https_download.csdn.net_download_badao_liumang_qizhi_10549085]: https://download.csdn.net/download/badao_liumang_qizhi/10549085