JPA Criteria API Queries (CriteriaBuilder, CriteriaQuery) Create Dynamic Query instead of appending String

Removed

Here is an example about how to create a Dynamic Query.

 This is very efficient when you have a method where some parameters may be null. so instead of creating a String builder (or String Buffer) and append the SQL Query, it is better to use the Criteria API Queries.

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public List<Devices> findDevice(String enterpriseId, List<String> modelIds, List<String> deviceIds, Date constructionDate) { CriteriaBuilder builder = entityManager.getCriteriaBuilder(); CriteriaQuery<Devices> query = builder.createQuery(Devices.class); Root<Devices> deviceRoot = query.from(Devices.class); List<Predicate> predicateList = new ArrayList<Predicate>(); if(enterpriseId !=null ){ predicateList.add(builder.equal(deviceRoot.get("enterprise").get("enterpriseId"), enterpriseId)); } if(modelIds != null && !modelIds.isEmpty()){ predicateList.add(builder.isTrue(deviceRoot.get("deviceModel").get("modelId").in(modelIds))); } if(deviceIds != null && !deviceIds.isEmpty()){ predicateList.add(builder.isTrue(deviceRoot.get("deviceId").in(deviceIds))); } predicateList.add(builder.greaterThan(deviceRoot.<Date>get("constructionDate"), constructionDate)); query.where(builder.and(predicateList.toArray(new Predicate[predicateList.size()]))); return entityManager.createQuery(query).getResultList(); }

Hope it helped you :)