springboot 之jpa高级查询操作

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<user,long>,jpaspecificationexecutor<user>,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<user> 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<address> 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<object[]> 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<object[]> 项目中一般封装成vo 类,或者list<map<string,object>> 的形式

github项目地址 https://github.com/christain1993/springbootintegration

补充：springbootjpa的复杂查询

分页

/**
   * 条件查询+分页
   * @param wheremap
   * @param page
   * @param size
   * @return
   */
  public page<casemanage> findsearch(map wheremap, int page, int size,integer createid) {
    sort sort = new sort(sort.direction.desc,"id");
    specification<casemanage> specification = createspecification(wheremap,createid);
    pagerequest pagerequest = new pagerequest(page,size,sort);
    return casedao.findall(specification, pagerequest);
  }
  
  /**
   * 条件查询
   * @param wheremap
   * @return
   */
  public list<casemanage> findsearch(map wheremap,integer createid) {
    specification<casemanage> specification = createspecification(wheremap, createid);
    return casedao.findall(specification);
  }
  
  /**
   * 动态条件构建
   * @param searchmap
   * @return
   */
  private specification<casemanage> createspecification(map searchmap,integer createid) {
    return new specification<casemanage>() {
      @override
      public predicate topredicate(root<casemanage> root, criteriaquery<?> query, criteriabuilder cb) {
        list<predicate> predicatelist = new arraylist<predicate>();
        // 案件名称
        if (searchmap.get("case_name")!=null && !"".equals(searchmap.get("case_name"))) {
          predicatelist.add(cb.like(root.get("case_name").as(string.class), "%"+(string)searchmap.get("case_name")+"%"));
        }
        // 案件编号uuid类型
        if (searchmap.get("case_uuid")!=null && !"".equals(searchmap.get("case_uuid"))) {
          predicatelist.add(cb.equal(root.get("case_uuid").as(string.class), (string)searchmap.get("case_uuid")));
        }
        return cb.and( predicatelist.toarray(new predicate[predicatelist.size()]));
      }
    };
  }

or查询

想实现这样的效果

where （state=1 or state=2）and name='zhangsan'

java代码

list<predicate> predicatelist = new arraylist<predicate>();
predicate or = cb.or(cb.and(cb.equal(root.get("case_authority").as(string.class), "0")), cb.and(cb.equal(root.get("create_id").as(string.class), string.valueof(createid))));
predicatelist.add(or);

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。如有错误或未考虑完全的地方，望不吝赐教。