springDataJpa入门教程（2）-Specification动态条件查询+排序+分页
springDataJpa入门教程
-
springDataJpa入门教程（1）-基于springBoot的基本增删改查
-
springDataJpa入门教程（2）-Specification动态条件查询+排序+分页
-
springDataJpa入门教程（3-1）-基于EntityManager原生sql多表联合查询+动态条件查询+分页
-
springDataJpa入门教程（3-2）-基于EntityManager原生sql多表联合查询+动态条件查询+分页返回自定义实体类对象
-
springDataJpa入门教程（4）-Example单表动态条件查询+分页
-
springDataJpa入门教程（5）-单表动态条件查询+分页
-
springDataJpa入门教程（6）-多表动态条件查询+分页
-
springDataJpa入门教程（7）-基于springDataJpa投影(Projection)返回自定义实体类对象
-
springDataJpa入门教程（8）-JPA EnableJpaAuditing 审计功能
-
springDataJpa入门教程（9）-spring jpa实体属性类型转换器AttributeConverter的用法
-
springDataJpa入门教程（10）-JPA使用过程中遇到的坑及解决方法
springDataJpa入门教程（2）-Specification动态条件查询+排序+分页
上一篇，讲解了springDataJpa的基本增删改查操作，下面接着上一篇的内容讲解使用springDataJpa来实现复杂查询。通常，由前端传递到后端的查询条件是可变的，这就要求查询的sql语句也是动态可变的，很多情况下数据量是很大的，需要用分页展示数据，甚至还要求查询的结果按照某个属性排序。下面来讲解使用Specification来实现复杂查询。由于本人水平有限，教程中难免出现错误，敬请谅解，欢迎大家批评指正。源码地址：源码下载地址。java学习交流群：184998348,欢迎大家一起交流学习。
Specification动态条件查询+排序+分页
下面是这一节会用到的实体类 User类以及UserDTO类.
1). User类
package com.thizgroup.jpa.study.model;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
@Entity
//这里User类对应的表是tb_user
@Table(name = "tb_user")
@Data//使用lombok生成getter、setter
@NoArgsConstructor//使用lombok生成无参构造方法
public class User {
@Id
//指定id生成策略为自增
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
//定义属性名对应的数据库表字段名称
@Column(name = "name",columnDefinition = "varchar(64)")
private String name;
@Column(name = "mobile",columnDefinition = "varchar(64)")
private String mobile;
@Column(name = "email",columnDefinition = "varchar(64)")
private String email;
@Column(name = "age",columnDefinition = "smallint(64)")
private Integer age;
@Column(name = "birthday",columnDefinition = "timestamp")
private Date birthday;
//地址
@Column(name = "address_id",columnDefinition = "bigint(20)")
private Long addressId;
@Column(name = "create_date",columnDefinition = "timestamp")
private Date createDate;
@Column(name = "modify_date",columnDefinition = "timestamp")
private Date modifyDate;
@Builder(toBuilder = true)//Builder注解可以实现链式编写，后面会用过
public User(Long id,String name, String mobile, String email, Integer age, Date birthday,
Long addressId) {
this.id = id;
this.name = name;
this.mobile = mobile;
this.email = email;
this.age = age;
this.birthday = birthday;
this.addressId = addressId;
}
}
2). UserDTO类
package com.thizgroup.jpa.study.dto;
import java.util.Date;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data//使用lombok生成getter、setter
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class UserDTO {
private Long id;
private String name;//姓名
private Integer age;//年龄
private String mobile;//手机号
private String email;//邮箱
private Date birthday;//生日
private Date createDate;//创建时间
private Date modifyDate;//修改时间
private Date startTime;//开始时间
private Date endTime;//结束时间
}
1.需求：根据动态查询条件查询用户分页数据，并按照按照创建时间倒序排序，动态查询条件：用户名、手机号、邮箱模糊查询，年龄精确查询，生日按照时间段查询。
首先，在IUserService接口中添加一个方法，
package com.thizgroup.jpa.study.service;
import com.thizgroup.jpa.study.dto.PageRecord;
import com.thizgroup.jpa.study.dto.UserDTO;
import com.thizgroup.jpa.study.dto.UserProjection;
import com.thizgroup.jpa.study.model.User;
import java.util.List;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
/**
* 用户服务
*/
public interface IUserService {
/**
* 查询用户分页信息
* @param userDTO
* @return
*/
Page findUserListByPage(UserDTO userDTO, Pageable pageable);
}
下面在UserServiceImpl实现类中实现这个方法，
package com.thizgroup.jpa.study.service.impl;
import com.thizgroup.jpa.study.dao.UserRepository;
import com.thizgroup.jpa.study.dto.UserDTO;
import com.thizgroup.jpa.study.model.User;
import com.thizgroup.jpa.study.service.IUserService;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.stream.Collectors;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Order;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.Assert;
@Service
@Transactional(readOnly = false,propagation = Propagation.REQUIRED)
public class UserServiceImpl implements IUserService {
@Autowired
private UserRepository userRepository;
@Override
//Specification 实现单表多条件分页查询及排序
public Page<User> findUserListByPage(UserDTO userDTO, Pageable pageable) {
Specification<User> specification = new Specification<User>() {
@Override
public Predicate toPredicate(Root<User> root, CriteriaQuery<?> criteriaQuery,
CriteriaBuilder criteriaBuilder) {
List<Predicate> andList = new ArrayList<>();//用来封装and条件
List<Predicate> orList = new ArrayList<>();//用来封装or条件
if(userDTO != null){
if(StringUtils.isNotBlank(userDTO.getName())){
//模糊查询
Predicate predicate = criteriaBuilder.like(root.get("name"), "%" + userDTO.getName() + "%");
andList.add(predicate);
}
if(null != userDTO.getAge()){
//精确查询
Predicate predicate = criteriaBuilder.equal(root.get("age"), userDTO.getAge());
andList.add(predicate);
}
//求生日在某个时间段范围内的用户
if(null != userDTO.getStartTime()){
//大于等于
Predicate predicate = criteriaBuilder
.greaterThanOrEqualTo(root.get("birthday"), userDTO.getStartTime());
andList.add(predicate);
}
if(null != userDTO.getEndTime()){
//小于等于
Predicate predicate = criteriaBuilder
.lessThanOrEqualTo(root.get("birthday"), userDTO.getEndTime());
andList.add(predicate);
}
if(StringUtils.isNotBlank(userDTO.getMobile())){
Predicate predicate = criteriaBuilder.like(root.get("mobile"), "%"+userDTO.getMobile()+"%");
orList.add(predicate);
}
if(StringUtils.isNotBlank(userDTO.getEmail())){
Predicate predicate = criteriaBuilder.like(root.get("email"), "%"+userDTO.getEmail()+"%");
orList.add(predicate);
}
}
Predicate andPredicate = null;
Predicate orPredicate = null;
//拼接and条件
if(andList.size()>0){
//转换为数组
Predicate[] predicates = andList.toArray(new Predicate[]{});
andPredicate = criteriaBuilder.and(predicates);
}
//拼接or条件
if(orList.size()>0){
//转换为数组
Predicate[] predicates = orList.toArray(new Predicate[]{});
orPredicate = criteriaBuilder.or(predicates);
}
//拼接查询条件
List<Predicate> predicates = new ArrayList<>();
if(andPredicate != null) predicates.add(andPredicate);
if(orPredicate != null) predicates.add(orPredicate);
Predicate predicate = null;
if(predicates.size()>0){
//转换为数组
Predicate[] predicateArray = predicates.toArray(new Predicate[]{});
predicate = criteriaBuilder.and(predicateArray);
}
List<Order> orderList = new ArrayList<>();//封装排序条件
//按照创建时间 倒序排序
orderList.add(criteriaBuilder.desc(root.get("createDate")));
// 按照生日顺序排序
//orderList.add(criteriaBuilder.asc(root.get("birthday")));
//设置排序条件
criteriaQuery.orderBy(orderList);
//返回查询条件
return predicate;
}
};
return userRepository.findAll(specification,pageable);
}
其中， userRepository的 Page findAll( Specification specification, Pageable pageable );是由JPA提供的方法，我们只需要提供查询条件以及分页参数即可，这里强调一下，JPA的分页是从0开始的，0表示第一页。
接下来，写一个单元测试来验证上述代码，
package com.thizgroup.jpa.study.service;
import com.thizgroup.jpa.study.JpaApplication;
import com.thizgroup.jpa.study.dto.UserDTO;
import com.thizgroup.jpa.study.model.User;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.test.annotation.Rollback;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
@SpringBootTest(classes={JpaApplication.class})
@RunWith(SpringJUnit4ClassRunner.class)
@Transactional(readOnly = false,propagation = Propagation.REQUIRED)
public class UserServiceImplTest {
@Autowired
private IUserService userService;
private SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
@Test
public void findUserListByPageTest() throws Exception{
UserDTO userDTO = new UserDTO();
//userDTO.setName("张");
//userDTO.setAge(50);
//userDTO.setStartTime(dateFormat.parse("2001-09-16 08:00:00"));
//userDTO.setEndTime(dateFormat.parse("2008-09-15 08:00:00"));
userDTO.setMobile("158989");
userDTO.setEmail("hu");
//注意：jpa的分页是从0开始的
Page<User> pageList = userService.findUserListByPage(userDTO, PageRequest.of(0, 15));
System.out.println("分页信息：");
System.out.println("总记录数："+pageList.getTotalElements()+",总页数："+pageList.getTotalPages());
System.out.println("页码："+(pageList.getNumber()+1)+",每页条数："+pageList.getSize());
List<User> content = pageList.getContent();
content = null == content? new ArrayList<>() : content;
content.forEach(user->System.out.println(user));
}
}
执行一下单元测试，结果如下：
分页信息：
总记录数：2,总页数：1
页码：1,每页条数：15
User(id=3, name=诸葛亮, mobile=158989989, email=zhu@qq.com, age=54, birthday=2001-09-16 08:00:00.0, addressId=22, createDate=2019-09-06 05:50:01.0, modifyDate=2019-08-08 05:46:17.0)
User(id=1, name=张三, mobile=156989989, email=hu@qq.com, age=35, birthday=2008-09-16 08:00:00.0, addressId=11, createDate=2019-08-06 05:50:01.0, modifyDate=2019-08-08 05:46:11.0)
至此，springDataJpa实现Specification动态条件查询+排序+分页就介绍完了，有需要源码的朋友，请到git上下载源码，源码地址：源码下载地址。java学习交流群：184998348,欢迎大家一起交流学习。