Spring Data JPA

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.fndsoft.springDataJpaProject.pojo.Student; import com.fndsoft.springDataJpaProject.repository.StudentJpaSpecificationExcutor; public class StudentJpaSpecificationExcutorTest { private ApplicationContext ctx = null; private StudentJpaSpecificationExcutor studentJpaSpecificationExcutor = null; @Before public void setUp(){ ctx = new ClassPathXmlApplicationContext("beans.xml"); studentJpaSpecificationExcutor = ctx.getBean(StudentJpaSpecificationExcutor.class); System.out.println("setup"); } @After public void tearDown(){ ctx = null; System.out.println("teardown"); } //结合JpaSpecificationExcutor接口 //分页加排序加条件age>23 @Test public void testPageAndSort(){ System.out.println("start"); Order order = new Order(Direction.ASC,"sage"); Sort sort = new Sort(order); Pageable pageable = new PageRequest(0,2,sort); Specification<Student> specification = new Specification<Student>() { //toPredicate就是查询条件 //root根对象表示实体类,要查询的类型,query所需要添加查询条件,cb构建Predicate @Override public Predicate toPredicate(Root<Student> root, CriteriaQuery<?> query, CriteriaBuilder cb) { // TODO Auto-generated method stub Path path = root.get("sage");//能获取到Student的sage的路径 return cb.gt(path, 23); } }; Page<Student> page = studentJpaSpecificationExcutor.findAll(specification, pageable); System.out.println("查询的总页数:"+page.getTotalPages()); System.out.println("查询的记录数:"+page.getTotalElements()); System.out.println("查询当前的第几页:"+(page.getNumber()+1)); System.out.println("查询当前页面的集合:"+page.getContent()); System.out.println("查询当前页面的记录数:"+page.getNumberOfElements()); System.out.println("started"); } }