package com.zuidaima.springdata.service.impl;

import java.util.ArrayList;
import java.util.List;

import javax.annotation.Resource;
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.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.jpa.domain.Specification
 
;
import org.springframework.stereotype.Service;

import com.zuidaima.springdata.entity.User;
import com.zuidaima.springdata.repository.UserRepository;
import com.zuidaima.springdata.service.UserService;

/**
 * *@author javaniu 2013-06-04 22:27:23
 */

@Service
public class UserServiceImpl implements UserService
 
 {

	@Resource
	public UserRepository userRepository;

	@Override
	public User findOneByName(final String name) {
		Specification<User> specification = new Specification<User>() {
			@Override
			public Predicate toPredicate(Root<User> root,
					CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
				Predicate _name = criteriaBuilder.equal(root.get("name"), name);
				return criteriaBuilder.and(_name);
			}
		};
		return userRepository.findOne(specification);
	}

	@Override
	public Page<User> findAllByLargeThanId(final Long id, int page, int count,
			Sort sort) {
		Specification<User> specification = new Specification<User>() {
			@Override
			public Predicate toPredicate(Root<User> root,
					CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
				Path<Long> $id = root.get("id");
				Predicate _id = criteriaBuilder.gt($id, id);
				return criteriaBuilder.and(_id);
			}
		};
		Pageable pageable = new PageRequest(page - 1, count, sort);
		return userRepository.findAll(specification, pageable);
	}

	@Override
	public User findAllByIdAndName(final Long id, final String name) {
		Specification<User> specification = new Specification<User>() {
			@Override
			public Predicate toPredicate(Root<User> root,
					CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
				List<Predicate> predicates = new ArrayList<Predicate>();
				Path<Long> $id = root.get("id");
				Predicate _id = criteriaBuilder.equal($id, id);
				predicates.add(_id);
				Path<Long> $name = root.get("name");
				Predicate _name = criteriaBuilder.equal($name, name);
				predicates.add(_name);
				return criteriaBuilder.and(predicates
						.toArray(new Predicate[] {}));
			}
		};
		return userRepository.findOne(specification);
	}

	@Override
	public Page<User> findAllByLikeName(final String name, int page, int count) {
		Specification<User> specification = new Specification<User>() {
			@Override
			public Predicate toPredicate(Root<User> root,
					CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
				Path<String> _name = root.get("name");
				Predicate _key = criteriaBuilder.like(_name, "%" + name + "%");
				return criteriaBuilder.and(_key);
			}
		};
		Sort sort = new Sort(Direction.DESC, "id");
		Pageable pageable = new PageRequest(page - 1, count, sort);
		return userRepository.findAll(specification, pageable);
	}

	@Override
	public Page<User> findAllByInIds(final List<Long> ids) {
		Specification<User> specification = new Specification<User>() {
			@Override
			public Predicate toPredicate(Root<User> root,
					CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
				return criteriaBuilder.in(root.get("id")).value(ids);
			}
		};
		int page = 1;
		int count = ids.size();
		Sort sort = new Sort(Direction.DESC, "id");
		Pageable pageable = new PageRequest(page - 1, count, sort);
		return userRepository.findAll(specification, pageable);
	}

	@Override
	public List<User> findAllByIds(List<Long> ids) {
		return userRepository.findAllByIds(ids);
	}

	@Override
	public User findAllByName(String name) {
		return userRepository.findAllByName(name);
	}

}

=====================================  華麗分割線  ===============================================

以下是我在專案中的實際運用：

1.實體類：GsTest(這裡就不貼程式碼了)

2.Dao層：

	@Repository
	public interface GsTestDao extends JpaRepository<GsTest, Long>,JpaSpecificationExecutor<GsTest>{
 
	}

3.Service層 :（也可以是單獨的某個引數，詳情見上面），page:頁數，conut:每頁的條數，sort:排序

	Page<GsTest> findOneByName(GsTest gsTest,int page,int count,Sort sort);

4.ServiceImpl層

	//分頁  條件為年齡和 姓名。
@Override
public Page<GsTest> findOneByName(final GsTest gsTest,int page,int count,Sort sort) {
Specification<GsTest> specification = new Specification<GsTest>() {
@Override
public Predicate toPredicate(Root<GsTest> root,
CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
List<Predicate> predicates = new ArrayList<Predicate>();
//引數非空判斷。不為空則加此條件
if (!gsTest.getAge().isEmpty()) {
Predicate _age = criteriaBuilder.equal(root.get("age"), gsTest.getAge());
predicates.add(_age);
System.out.println("_age:"+gsTest.getAge().isEmpty());
}
Predicate _name = criteriaBuilder.equal(root.get("name"), gsTest.getName());
predicates.add(_name);

//return criteriaBuilder.and(_name);return criteriaBuilder.and(predicates.toArray(new Predicate[]{}));
}
};

4.controller:控制層

	/**
 * 
 * @param gsTestDto 實體，用來接收傳來JSON型別引數
 * @param pageNumber  頁數
 * @param pageSize   條數
 * @return
 */
@RequestMapping(value="/fin",method = RequestMethod.POST)
@ResponseBody
public  Page<GsTest> findTest(@RequestBody GsTestDto gsTestDto,@RequestParam(value = "page", defaultValue = "1") int pageNumber,
@RequestParam(value = "size", defaultValue = Constants.PAGE_SIZE_10) int pageSize){
GsTest gsTest = new GsTest();
gsTest=converterIn.convertIn(gsTestDto);
System.out.println("GsTestDto:"+gsTest);
//排序
Sort sort = new Sort(Direction.ASC, "id");
Page<GsTest> findOneByName = gsTestDaoService.findOneByName(gsTest,pageNumber,pageSize,sort);


return findOneByName;
}

到此，條件分頁就完成了。看看測試結果：

我用的是 谷歌的Postman來進行測試：

1.傳參：

  {
    "name": "jak"
}

結果：

{
  "content": [
    {
      "id": 3,
      "properties_string": null,
      "name": "jak",
      "age": "21",
      "sex": "女",
      "status": "1",
      "certime": "2013-05-11 09:00:00"
    },
    {
      "id": 4,
      "properties_string": null,
      "name": "jak",
      "age": "21",
      "sex": "女",
      "status": "1",
      "certime": "2013-05-11 09:00:00"
    },
    {
      "id": 5,
      "properties_string": null,
      "name": "jak",
      "age": "21",
      "sex": "女",
      "status": "1",
      "certime": "2013-05-11 09:00:00"
    }
  ],
  "size": 10,
  "number": 0,
  "sort": [
    {
      "direction": "ASC",
      "property": "id",
      "ascending": true
    }
  ],
  "lastPage": true,
  "firstPage": true,
  "totalPages": 1,
  "totalElements": 3,
  "numberOfElements": 3
}

2.傳錯誤的引數：

{
    "name": "jak",
    "age":"22"
}

結果：

{
  "content": [],
  "size": 10,
  "number": 0,
  "sort": [
    {
      "direction": "ASC",
      "property": "id",
      "ascending": true
    }
  ],
  "lastPage": true,
  "firstPage": true,
  "totalPages": 0,
  "totalElements": 0,
  "numberOfElements": 0
}

可以看得到 查不到的時候。content 是空值！

到此，簡單的條件分頁查詢就完成了，我也是小白，不妥之處見諒！

===============2017年3月2日10:28:46=======  華麗分割線  ===============================================
注：接著上面的
實體類：prid
         實體類中有一個時間屬性：
              private Date beginTime;               

               private Date endTime;