概述

　　ORM映射为我们带来便利的同时，也失去了较大灵活性，如果SQL较复杂，要进行动态查询，那必定是一件头疼的事情（也可能是lz还没发现好的方法），记录下自己用的三种复杂查询方式。

环境

springBoot

IDEA2017.3.4

JDK8

pom.xml

<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://.xmlxy.seasgame.entity;import io.swagger.annotations.ApiModel;import lombok.Data;import javax.persistence.*;import javax.print.attribute.standard.MediaSize;import java.io.Serializable;/** * * Description:学生对象 * @param * @author hwc * @date 2019/8/8 */@Entity@Table(name = "t_base_student")@ApiModel@Datapublic class StudentEntity implements Serializable{ private static final long serialVersionUID = 546L; @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "student_id") private Integer studentId; @Column(name = "student_grade") private Integer studentGrade; @Column(name = "student_class") private Integer studentClass; @Column(name = "address") private String address; @Column(name = "telephone") private Integer telephone; @Column(name = "real_name") private String realName; @Column(name = "id_number") private String idNumber; @Column(name = "study_id") private String studyId; @Column(name = "is_delete") private int isDelete; @Column(name = "uuid") private String uuid;}

dao层

public interface StudentDao extends JpaRepository<StudentEntity,Integer>,JpaSpecificationExecutor{}

动态查询

public Page<StudentEntity> getTeacherClassStudent(int pageNumber,int pageSize,int gradeId, int classId,String keyword) { pageNumber = pageNumber < 0 ? 0 : pageNumber; pageSize = pageSize < 0 ? 10 : pageSize; Specification<StudentEntity> specification = new Specification<StudentEntity>() { @Override public Predicate toPredicate(Root<StudentEntity> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) { //page : 0 开始, limit : 默认为 10 List<Predicate> predicates = new ArrayList<>(); predicates.add(criteriaBuilder.equal(root.get("studentGrade"),gradeId)); predicates.add(criteriaBuilder.equal(root.get("studentClass"),classId)); if (!Constant.isEmptyString(keyword)) { predicates.add(criteriaBuilder.like(root.get("realName").as(String.class),"%" + keyword + "%")); } return criteriaBuilder.and(predicates.toArray(new Predicate[predicates.size()])); } }; PageRequest page = new PageRequest(pageNumber,pageSize,Sort.Direction.ASC,"studentId"); Page<StudentEntity> pages = studentDao.findAll(specification,page); return pages; }

因为这个项目应用比较简单，所以条件只有一个，如果条件较多，甚至可以定义一个专门的类去接收拼接参数，然后判

断，成立就add进去。

总结

以上所述是小编给大家介绍的JPA多条件复杂SQL动态分页查询功能，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！
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