SpringBoot集成JPA实现分页和CRUD
文章目录
- SpringBoot集成JPA实现分页和CRUD
- pom.xml
- application.properties
- addCategory.jsp
- editCategory.jsp
- hello.jsp
- listCategory.jsp
- Category
- CategoryDAO
- CategoryService
- CategoryServiceImpl
- Page4Navigator
- RedisConfig
- CategoryController
- HelloController
懒得敲代码，直接拷贝： SpringBoot集成JPA实现分页和CRUD
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.3.2.RELEASE</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.moon</groupId><artifactId>springboot</artifactId><version>0.0.1-SNAPSHOT</version><name>springboot</name><description>springboot</description><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-test</artifactId><scope>test</scope></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><scope>test</scope></dependency><!--要使用jsp添加这个--><dependency><groupId>org.apache.tomcat.embed</groupId><artifactId>tomcat-embed-jasper</artifactId><scope>provided</scope></dependency><dependency><groupId>javax.servlet</groupId><artifactId>jstl</artifactId><scope>provided</scope></dependency><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><scope>provided</scope></dependency><!--数据库--><!-- mysql--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.30</version></dependency><!-- jpa--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>application.properties
填自己的数据库和密码
spring.mvc.view.prefix=/WEB-INF/jsp/
spring.mvc.view.suffix=.jsp
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/how2java?characterEncoding=UTF-8
spring.datasource.username=
spring.datasource.password=
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.properties.hibernate.hbm2ddl.auto=update###########################redis#########################
#Redis数据库索引（默认为0）
spring.redis.database=0
#Redis服务器地址
spring.redis.host=127.0.0.1
#Redis服务器连接端口
spring.redis.port=6379
#Redis服务器连接密码（默认为空）
spring.redis.password=
#连接池最大连接数（使用负值表示没有限制）
spring.redis.pool.max-active=10
#连接池最大阻塞等待时间（使用负值表示没有限制）
spring.redis.pool.max-wait=-1
#连接池中的最大空闲连接
spring.redis.pool.max-idle=8
#连接池中的最小空闲连接
spring.redis.pool.min-idle=0
#连接超时时间（毫秒）
spring.redis.timeout=0spring.jpa.show-sql=true
addCategory.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%>
<div style="margin: 0px auto; width: 500px"><form action="updateCategory" method="post">name:<input name="name" value="${category.name}"><br><button type="submit">提交</button></form>
</div>
editCategory.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8" isELIgnored="false"%><div style="margin: 0px auto; width: 500px"><form action="updateCategory" method="post">name:<input name="name" value="${c.name}"><br><input name="id" type="hidden" value="${c.id}"><button type="submit">提交</button></form>
</div>
hello.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8" isELIgnored="false"%><div style="margin: 0px auto; width: 500px"><form action="updateCategory" method="post">name:<input name="name" value="${c.name}"><br><input name="id" type="hidden" value="${c.id}"><button type="submit">提交</button></form>
</div>
listCategory.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<div align="center"></div>
<div style="width: 500px;margin: 20px auto;text-align: center"><table align="center" border="1" cellspacing="0"><caption>员工<a href="addCategory">添加</a></caption><thead><tr><th>id</th><th>name</th><th>编辑</th><th>删除</th></tr></thead><tbody><c:forEach items="${page.content}" var="c" varStatus="st"><tr><td>${c.id}</td><td>${c.name}</td><td><a href="editCategory?id=${c.id}">编辑</a></td><td><a href="deleteCategory?id=${c.id}">删除</a></td></tr></c:forEach></tbody></table><div><a href="?start=0">【首页】</a><a href="?start=${page.number-1}">【上一页】</a><a href="?start=${page.number+1}">【下一页】</a><a href="?start=${page.totalPages-1}">【末页】</a></div><div></div>
</div>Category
package com.moon.springboot.pojo;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;import javax.persistence.*;/*** @Author moon* @Date 2023/9/26 21:05* @Description*/
@Entity
@Table(name = "category_")
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Category {@Id//表明自增长方式@GeneratedValue(strategy = GenerationType.IDENTITY)@Column(name = "id")private Integer id;@Column(name = "name")private String name;
}
CategoryDAO
package com.moon.springboot.dao;import com.moon.springboot.pojo.Category;
import org.springframework.data.jpa.repository.JpaRepository;/*** @Author moon* @Date 2023/9/26 21:18* @Description* 泛型<Category, Integer> 表示这个是针对Category类的DAO,Integer表示主键是Integer类型。* JpaRepository 这个父接口，就提供了CRUD, 分页等等一系列的查询了*/
public interface CategoryDAO extends JpaRepository<Category, Integer> {
}CategoryService
package com.moon.springboot.service;import com.moon.springboot.pojo.Category;
import com.moon.springboot.util.Page4Navigator;
import org.springframework.data.domain.Pageable;public interface CategoryService {public Page4Navigator<Category> list(Pageable pageable);public void save(Category category);public void delete(int id);public Category get(int id);
}CategoryServiceImpl
package com.moon.springboot.service.impl;import com.moon.springboot.dao.CategoryDAO;
import com.moon.springboot.pojo.Category;
import com.moon.springboot.service.CategoryService;
import com.moon.springboot.util.Page4Navigator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheConfig;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Service;@Service
@CacheConfig(cacheNames="category")
public class CategoryServiceImpl implements CategoryService {@AutowiredCategoryDAO categoryDAO;@Override@Cacheable(key="'category '+#p0.offset + '-' + #p0.pageSize ")public Page4Navigator<Category> list(Pageable pageable) {Page<Category> pageFromJPA= categoryDAO.findAll(pageable);Page4Navigator<Category> page = new Page4Navigator<>(pageFromJPA,5);return page;}@Override@Cacheable(key="'category '+ #p0")public Category get(int id) {Category c =categoryDAO.getOne(id);return c;}@Override@CacheEvict(allEntries=true)
// @CachePut(key="'category '+ #p0")public void save(Category category) {// TODO Auto-generated method stubcategoryDAO.save(category);}@Override@CacheEvict(allEntries=true)
// @CacheEvict(key="'category '+ #p0")public void delete(int id) {// TODO Auto-generated method stubcategoryDAO.deleteById(id);}}Page4Navigator
在执行查询方法时，可以传入一个PageRequest对象，代表进行分页查询。
PageRequest对象代表了查询的条件和约束，通常包含当前页数，每页几条数据。
也可以在分页查询时指定Direction或Sort。
查询的结果为Page对象，包含当前页所及所有数据相关信息。
Page对象常用方法：
getTotalPages() 总共有多少页
getTotalElements() 总共有多少条数据
getNumber() 获取当前页码
getSize() 每页指定有多少元素
getNumberOfElements() 当前页实际有多少元素
hasContent() 当前页是否有数据
getContent() 获取当前页中所有数据（List）
getSort() 获取分页查询排序规则
isFirst() 当前页是否是第一页
isLast() 当前页是否是最后一页
hasPrevious() 是否有上一页
hasNext() 是否有下一页
package com.moon.springboot.util;import java.util.List;import org.springframework.data.domain.Page;public class Page4Navigator<T> {Page<T> page4jpa;//导航分页的页码数int navigatePages;//要打印的总页数int totalPages;int number;long totalElements;int size;int numberOfElements;List<T> content;boolean isHasContent;boolean first;boolean last;boolean isHasNext;boolean isHasPrevious;int[] navigatepageNums;public Page4Navigator() {//这个空的分页是为了 Redis 从 json格式转换为 Page4Navigator 对象而专门提供的}public Page4Navigator(Page<T> page4jpa,int navigatePages) {this.page4jpa = page4jpa;this.navigatePages = navigatePages;totalPages = page4jpa.getTotalPages();number = page4jpa.getNumber() ;totalElements = page4jpa.getTotalElements();size = page4jpa.getSize();numberOfElements = page4jpa.getNumberOfElements();content = page4jpa.getContent();isHasContent = page4jpa.hasContent();first = page4jpa.isFirst();last = page4jpa.isLast();isHasNext = page4jpa.hasNext();isHasPrevious = page4jpa.hasPrevious();calcNavigatepageNums();}private void calcNavigatepageNums() {int navigatepageNums[];int totalPages = getTotalPages();int num = getNumber();//当总页数小于或等于导航页码数时if (totalPages <= navigatePages) {navigatepageNums = new int[totalPages];for (int i = 0; i < totalPages; i++) {navigatepageNums[i] = i + 1;}} else { //当总页数大于导航页码数时navigatepageNums = new int[navigatePages];int startNum = num - navigatePages / 2;int endNum = num + navigatePages / 2;if (startNum < 1) {startNum = 1;//(最前navigatePages页for (int i = 0; i < navigatePages; i++) {navigatepageNums[i] = startNum++;}} else if (endNum > totalPages) {endNum = totalPages;//最后navigatePages页for (int i = navigatePages - 1; i >= 0; i--) {navigatepageNums[i] = endNum--;}} else {//所有中间页for (int i = 0; i < navigatePages; i++) {navigatepageNums[i] = startNum++;}}}this.navigatepageNums = navigatepageNums;}public int getNavigatePages() {return navigatePages;}public void setNavigatePages(int navigatePages) {this.navigatePages = navigatePages;}public int getTotalPages() {return totalPages;}public void setTotalPages(int totalPages) {this.totalPages = totalPages;}public int getNumber() {return number;}public void setNumber(int number) {this.number = number;}public long getTotalElements() {return totalElements;}public void setTotalElements(long totalElements) {this.totalElements = totalElements;}public int getSize() {return size;}public void setSize(int size) {this.size = size;}public int getNumberOfElements() {return numberOfElements;}public void setNumberOfElements(int numberOfElements) {this.numberOfElements = numberOfElements;}public List<T> getContent() {return content;}public void setContent(List<T> content) {this.content = content;}public boolean isHasContent() {return isHasContent;}public void setHasContent(boolean isHasContent) {this.isHasContent = isHasContent;}public boolean isFirst() {return first;}public void setFirst(boolean first) {this.first = first;}public boolean isLast() {return last;}public void setLast(boolean last) {this.last = last;}public boolean isHasNext() {return isHasNext;}public void setHasNext(boolean isHasNext) {this.isHasNext = isHasNext;}public boolean isHasPrevious() {return isHasPrevious;}public void setHasPrevious(boolean isHasPrevious) {this.isHasPrevious = isHasPrevious;}public int[] getNavigatepageNums() {return navigatepageNums;}public void setNavigatepageNums(int[] navigatepageNums) {this.navigatepageNums = navigatepageNums;}}RedisConfig
package com.moon.springboot.config;import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.cache.RedisCacheWriter;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.serializer.*;import java.time.Duration;@Configuration
@EnableCaching
public class RedisConfig extends CachingConfigurerSupport {private RedisSerializer<String> keySerializer() {return new StringRedisSerializer();}private RedisSerializer<Object> valueSerializer() {return new GenericJackson2JsonRedisSerializer();//value值使用json序列化器}@Beanpublic CacheManager cacheManager(RedisConnectionFactory factory) {RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig();redisCacheConfiguration = redisCacheConfiguration.entryTtl(Duration.ofMinutes(30L))//设置缓存延时时间为30分钟.disableCachingNullValues()//如果是空值，不缓存.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(keySerializer()))//设置key值序列化.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(valueSerializer()));//设置value值序列化为jsonreturn RedisCacheManager.builder(RedisCacheWriter.nonLockingRedisCacheWriter(factory)).cacheDefaults(redisCacheConfiguration).build();}
}
CategoryController
package com.moon.springboot.web;import com.moon.springboot.pojo.Category;
import com.moon.springboot.service.CategoryService;
import com.moon.springboot.util.Page4Navigator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;@Controller
public class CategoryController {@AutowiredCategoryService categoryService;@RequestMapping("/listCategory")public String listCategory(Model m,@RequestParam(value = "start", defaultValue = "0") int start,@RequestParam(value = "size", defaultValue = "5") int size) throws Exception {start = start<0?0:start;Sort sort = Sort.by(Sort.Direction.DESC, "id");Pageable pageable = PageRequest.of(start, size, sort);Page4Navigator<Category> page =categoryService.list(pageable);m.addAttribute("page", page);return "listCategory";}@RequestMapping("/addCategory")public String addCategory(Category c) throws Exception {categoryService.save(c);return "redirect:listCategory";}@RequestMapping("/deleteCategory")public String deleteCategory(Category c) throws Exception {categoryService.delete(c.getId());return "redirect:listCategory";}@RequestMapping("/updateCategory")public String updateCategory(Category c) throws Exception {categoryService.save(c);return "redirect:listCategory";}@RequestMapping("/editCategory")public String editCategory(int id,Model m) throws Exception {Category c= categoryService.get(id);m.addAttribute("c", c);return "editCategory";}
}HelloController
package com.moon.springboot.web;import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.text.DateFormat;
import java.util.Date;/*** @Author moon* @Date 2023/9/25 21:17* @Description*/@Controller
public class HelloController {@RequestMapping("/hello")public String hello(Model model) {model.addAttribute("now", DateFormat.getDateTimeInstance().format(new Date()));return "hello";}@RequestMapping("/hello_1")public String hello_1(Model model) {model.addAttribute("now", DateFormat.getDateTimeInstance().format(new Date()));return "hello_1";}
}
