spring data 接口之 JpaRepository，JpaSpecificationExecutor

实体类

package com.wangh.model;import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
//可以使用name属性指定表名
@Entity(name="Person")
public class Person {
    private Integer id;private String name;private Integer age;@GeneratedValue@Idpublic Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}@Overridepublic String toString() {return "Person [id=" + id + ", name=" + name + ", age=" + age + "]";}}

接口

package com.wangh.repository;import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;import com.wangh.model.Person;
/*** JpaSpecificationExecutor 查询条件、分页和排序接口.* JpaRepository 继承于 PagingAndSortingRepository 接口, 拥有PagingAndSortingRepository 的所有方法，* 而JpaSpecificationExecutor 不属于Repository 体系。由于JpaSpecificationExecutor 并不继承repository 接口，* 所以它不能单独使用，只能和jpa Repository 一起用。 * @ClassName: PersonJpaSpecifactionRepository * @Description: TODO * @author Wanghao * @date 2017年6月13日 上午9:25:45*/
public interface PersonJpaSpecifactionRepository extends JpaSpecificationExecutor<Person>,JpaRepository<Person, Integer>{
    }

service

package com.wangh.service;import java.util.List;import javax.annotation.Resource;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.Transactional;import com.wangh.model.Person;
import com.wangh.repository.PersonCrudRepository;
import com.wangh.repository.PersonJpaSpecifactionRepository;
import com.wangh.repository.PersonPagingAndSortRepository;@Service
public class PersonService {@Resourceprivate PersonJpaSpecifactionRepository personJpaSpecifactionRepository;/*** 查询* @param spec 查询条件* @param pageable 分页排序* @return* Page<Person>* @author Wanghao*/public Page<Person> query(Specification<Person> spec, Pageable pageable){return personJpaSpecifactionRepository.findAll(spec, pageable);}
}

测试类

package springdata;import java.util.ArrayList;
import java.util.List;import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Path;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
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.data.domain.Sort.Direction;
import org.springframework.data.domain.Sort.Order;
import org.springframework.data.jpa.domain.Specification;import com.wangh.model.Person;
import com.wangh.service.PersonService;public class PersonRepositoryTest {private ApplicationContext ctx = null;private PersonService psv = null;@Beforepublic void before(){ctx = new ClassPathXmlApplicationContext("spring.xml");psv = ctx.getBean(PersonService.class);System.out.println("before");}@Afterpublic void after(){ctx = null;psv = null;System.out.println("after");}/*** * 按id降序并且age<15，分页* @author Wangh*/@Testpublic void query(){Specification<Person> spec = new Specification<Person>() {@Overridepublic Predicate toPredicate(Root<Person> root, CriteriaQuery<?> query, CriteriaBuilder cb) {Path path = root.get("age");return cb.lt(path, 15);}};Order order = new Order(Direction.DESC, "id");Sort sort = new Sort(order);Pageable pageable = new PageRequest(0, 3, sort);Page<Person> page = psv.query(spec, pageable);System.out.println("当前页码上行数："+page.getNumberOfElements());System.out.println("当前第几页："+page.getNumber()+1);System.out.println("总数："+page.getTotalElements());System.out.println("总页数："+page.getTotalPages());System.out.println("当前页内容："+page.getContent());}
}

测试结果