springboot jpa 多条件查询（单表）
需要实现的功能：
多个搜索输入框；全部不填，则查出所有列表；填了条件，就按条件查找；填的条件个数不定。
方法实现的核心：jpa自带的Specification<T>
（目前只需要单表，多表其实差不多）
话不多说，直接上代码。
实体类
1 import lombok.Data; 2 3 import javax.persistence.Entity; 4 import javax.persistence.Id; 5 6 /** 7 * Created by 孙义朗 on 2017/11/14 0014. 8 */ 9 @Entity 10 @Data 11 public class Employee { 12 @Id 13 private String id; 14 private String name; 15 private String age; 16 }
接口
1 2 3 import org.springframework.data.jpa.domain.Specification; 4 import org.springframework.data.jpa.repository.JpaRepository; 5 6 import java.util.List; 7 8 /** 9 * Created by 孙义朗 on 2017/11/14 0014. 10 */ 11 public interface EmployeeRepository extends JpaRepository<Employee, String>{ 12 List<Employee> findAll(Specification<Employee> spc, Pageable pageable); 13 }
控制器
1 2 3 import org.springframework.beans.factory.annotation.Autowired; 4 import org.springframework.data.domain.PageRequest; 5 import org.springframework.data.domain.Pageable; 6 import org.springframework.data.jpa.domain.Specification; 7 import org.springframework.web.bind.annotation.*; 8 9 import javax.persistence.criteria.*; 10 import java.util.ArrayList; 11 import java.util.List; 12 13 /** 14 * Created by 孙义朗 on 2017/11/14 0014. 15 */ 16 @RestController 17 public class EmployeeController { 18 @Autowired 19 EmployeeRepository employeeRepository; 20 21 //查询所有Employee 22 @PostMapping(value = "/getEmployee/{pageNum}/{pageSize}") 23 public List<Employee> getEmployee(@PathVariable("pageNum") Integer pageNum, 24 @PathVariable("pageSize") Integer pageSize, 25 @RequestBody Employee employee) { 26 Pageable pageable = new PageRequest(pageNum, pageSize); 27 List<Employee> eList = employeeRepository.findAll(new Specification<Employee>() { 28 @Override 29 public Predicate toPredicate(Root<Employee> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder cb) { 30 Path<String> id = root.get("id"); 31 Path<String> name = root.get("name"); 32 Path<String> age = root.get("age"); 33 List<Predicate> predicates = new ArrayList<>(); 34 if (employee.getId() != null && !employee.getId().equals("")) { 35 predicates.add(cb.like(id.as(String.class), "%" + employee.getId() + "%")); 36 } 37 if (employee.getName() != null && !employee.getName().equals("")) { 38 predicates.add(cb.like(name.as(String.class), "%" + employee.getName() + "%")); 39 } 40 if (employee.getAge() != null && !employee.getAge().equals("")) { 41 predicates.add(cb.like(age.as(String.class), "%" + employee.getAge() + "%")); 42 } 43 Predicate[] pre = new Predicate[predicates.size()]; 44 criteriaQuery.where(predicates.toArray(pre)); 45 return cb.and(predicates.toArray(pre)); 46 } 47 }, pageable); 48 49 return eList; 50 } 51 52 }
postman测试效果
（多表查询http://www.cnblogs.com/arrrrrya/p/7865090.html）
