springboot之jpa高级查询

springboot的jpa可以根据方法名自动解析sql 非常方便, 只需要在 dao接口中定义方法即可;

下面是一个 demo

package com.bus365.root.dao;


import java.io.Serializable;
import java.util.List;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;

import com.bus365.root.model.User;

public interface UserDao extends JpaRepository,JpaSpecificationExecutor,Serializable {

	User findByName(String name);

	User findByNameAndAge(String name, Integer age);

	User findByNameOrAge(String name, Integer age);

	
	/*@Query(value = "from User where name = :name")
	List findbyname(@Param("name") String name);*/
}

下面展示service层调用:

@Override
	public User findByName(String name) {
		User user = userDao.findByName(name);
		return user;
	}

	@Override
	public User findByNameAndAge(String name, Integer age) {
		User user = userDao.findByNameAndAge(name,age);
		return user;
	}

	@Override
	public User findByNameOrAge(String name, Integer age) {
		User user = userDao.findByNameOrAge(name,age);
		return user;
	}

具体的关键字，使用方法和生产成SQL如下表所示

Keyword	Sample	JPQL snippet
And	findByLastnameAndFirstname	… where x.lastname = ?1 and x.firstname = ?2
Or	findByLastnameOrFirstname	… where x.lastname = ?1 or x.firstname = ?2
Is,Equals	findByFirstnameIs,findByFirstnameEquals	… where x.firstname = ?1
Between	findByStartDateBetween	… where x.startDate between ?1 and ?2
LessThan	findByAgeLessThan	… where x.age < ?1
LessThanEqual	findByAgeLessThanEqual	… where x.age ⇐ ?1
GreaterThan	findByAgeGreaterThan	… where x.age > ?1
GreaterThanEqual	findByAgeGreaterThanEqual	… where x.age >= ?1
After	findByStartDateAfter	… where x.startDate > ?1
Before	findByStartDateBefore	… where x.startDate < ?1
IsNull	findByAgeIsNull	… where x.age is null
IsNotNull,NotNull	findByAge(Is)NotNull	… where x.age not null
Like	findByFirstnameLike	… where x.firstname like ?1
NotLike	findByFirstnameNotLike	… where x.firstname not like ?1
StartingWith	findByFirstnameStartingWith	… where x.firstname like ?1 (parameter bound with appended %)
EndingWith	findByFirstnameEndingWith	… where x.firstname like ?1 (parameter bound with prepended %)
Containing	findByFirstnameContaining	… where x.firstname like ?1 (parameter bound wrapped in %)
OrderBy	findByAgeOrderByLastnameDesc	… where x.age = ?1 order by x.lastname desc
Not	findByLastnameNot	… where x.lastname <> ?1
In	findByAgeIn(Collection ages)	… where x.age in ?1
NotIn	findByAgeNotIn(Collection age)	… where x.age not in ?1
TRUE	findByActiveTrue()	… where x.active = true
FALSE	findByActiveFalse()	… where x.active = false
IgnoreCase	findByFirstnameIgnoreCase	… where UPPER(x.firstame) = UPPER(?1)

 

下面介绍使用java原生的jpa操作数据库,对jpa熟悉的朋友应该很快就能理解,springboot使用原生jpa的关键是引入entitymanger

 

看一下service层

package com.bus365.root.service.impl;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import org.springframework.stereotype.Service;

import com.bus365.root.model.Address;
import com.bus365.root.service.AddressService;

@Service
public class AddressServiceImpl implements AddressService {

	@PersistenceContext
	private EntityManager entityManager;
	
	public List
 listAddress(){
		List resultList = entityManager.createNativeQuery("select * from address ", Address.class).getResultList();
		return resultList;
	}
}

注意 @PersistenceContext
    private EntityManager entityManager;
    动态引入entitymanger , 之后就能正常使用了;

    createNativeQuery是操作原生mysql方法;支持跨表查询;

jpa的事务 直接使用注解Transactional 参数rollbackon表示回滚条件, 这个注解一搬加在service层;  注意getSingleResult 如果查不到数据会报错;

@Transactional(rollbackOn= {Exception.class})
	public Address getAddressByid(Long id) {
		Address singleResult = null;
		try {
			singleResult = (Address) entityManager
					.createNativeQuery("select * from address where id = :id", Address.class).setParameter("id", id)
					.getSingleResult();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return singleResult;
	}

 

jpa实现多表联查;

@Transactional
	public List getUserWithAddrByid(Long id) {
		List resultList = entityManager.createNativeQuery(
				"select u.id id,u.age age,u.name name,a.name aname,a.completeaddress addre from user u left join address a on u.addressid = a.id where u.id = :id")
				.setParameter("id", id).getResultList();
		return resultList;
	}

      这是一个联查user 和address的例子, 返回的结果是个List 项目中一般封装成vo 类,或者List> 的形式

 

github项目地址   https://github.com/Christain1993/SpringBootIntegration