JPA实现动态查询
前言
之前使用jpa的时候一直感慨它的一些原来就有的方法很好用，一边不是很习惯这种不是xml写sql的方式，尤其在用习惯了mybatis之后，在使用jpa写动态查询的时候真的一头雾水，直到发现了Specification 这个神奇的东西，使用下来觉得他和mybatis plus的条件构造器很像，而且可以实现动态查询，特意记录一下
代码
JPA
代码语言：javascript复制 List<Apply> findAll(Specification<Apply> specification);service
代码语言：javascript复制 public List<Apply> getAllDynamatic(Apply apply) {
Specification<Apply> queryCondition = new Specification<Apply>() {
@Override
public Predicate toPredicate(Root<Apply> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
List<Predicate> predicateList = new ArrayList<>();
// 根据传递的对象来进行条件的构造
if (apply.getId() != null) {
predicateList.add(criteriaBuilder.equal(root.get("id"), apply.getId()));
}
if (apply.getState() != null) {
predicateList.add(criteriaBuilder.equal(root.get("state"), apply.getState()));
}
if (apply.getAwardtype() != null) {
predicateList.add(criteriaBuilder.equal(root.get("awardtype"), apply.getAwardtype()));
}
if (apply.getStudentid() != null) {
predicateList.add(criteriaBuilder.equal(root.get("studentid"), apply.getStudentid()));
}
if (apply.getInfo() != null) {
predicateList.add(criteriaBuilder.equal(root.get("info"), apply.getInfo()));
}
if (apply.getName() != null) {
predicateList.add(criteriaBuilder.equal(root.get("name"), apply.getName()));
}
if (apply.getType() != null) {
predicateList.add(criteriaBuilder.equal(root.get("type"), apply.getType()));
}
if (apply.getTeacherid() != null) {
predicateList.add(criteriaBuilder.equal(root.get("teacherid"), apply.getTeacherid()));
}
if (apply.getTeacherstate() != null) {
predicateList.add(criteriaBuilder.equal(root.get("teacherstate"), apply.getTeacherstate()));
}
if (apply.getProcess() != null) {
predicateList.add(criteriaBuilder.equal(root.get("process"), apply.getProcess()));
}
if (apply.getProcess2() != null) {
predicateList.add(criteriaBuilder.equal(root.get("process2"), apply.getProcess2()));
}
return criteriaBuilder.and(predicateList.toArray(new Predicate[predicateList.size()]));
}
};
return applyRepos.findAll(queryCondition);
}这样就实现了jpa的动态查询
