JPA 通过Specification如何实现复杂查询

目录

• JPA 通过Specification实现复杂查询
• 下面就简单介绍一下Specification的使用
• spring-data-jpa Specification拼接复杂查询

JPA 通过Specification实现复杂查询

JPA中继承BaseRepo之后，可以使用最基本的增删改查，如果想实现复杂查询，则需要借助Specification来完成这个功能：

下面就简单介绍一下Specification的使用

public void findAll(ConstructPlanPageReqEntity constructPlanPageReqEntity) {
	Integer pageNum = page.getPageNum();
        Integer pageSize = page.getPageSize();
        String costType = constructPlanPageReqEntity.getCostType();
        String name = constructPlanPageReqEntity.getName();
        String planMoneyStart = constructPlanPageReqEntity.getPlanMoneyStart();
        String planMoneyEnd = constructPlanPageReqEntity.getPlanMoneyEnd();
        String singMoneyEnd = constructPlanPageReqEntity.getSingMoneyEnd();
        String signMoneyStart = constructPlanPageReqEntity.getSignMoneyStart();
        long projectId = Long.parseLong(constructPlanPageReqEntity.getProjectId());
        String status = constructPlanPageReqEntity.getStatus();
        //分页
        pageNum=pageNum-1;
        Pageable pageable = PageRequest.of(pageNum, pageSize);
//多条件匹配查询
        Specification specification= new Specification() {
            @Override
            public Predicate toPredicate(Root root, CriteriaQuery criteriaQuery, CriteriaBuilder criteriaBuilder) {
                ArrayList list = new ArrayList<>();
                Path costType1 = root.get("costType");
                Path name1 = root.get("name");
                Path projectId1 = root.get("projectId");
                Path