Exception in thread "main" java.util.ConcurrentModificationException

最新推荐文章于 2022-05-07 10:23:43 发布

最新推荐文章于 2022-05-07 10:23:43 发布 · 161 阅读

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#Java #thread #Hibernate #C #C++

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本文详细介绍了在使用Hibernate进行删除操作时遇到并发修改异常的解决方案，通过修改代码实现安全删除。具体步骤包括获取实体集合，遍历并检查目标ID，实现安全删除逻辑，并最终提交事务。


public void del(int id){
		session.beginTransaction().begin();
		Company c=(Company) session.get(Company.class, 1);
		Set set=c.getEmployees();
		Iterator it=set.iterator();
		while(it.hasNext()){
			Employee e=(Employee) it.next();
			System.out.println(e.getId());
			System.out.println(id);
			if(e.getId()==id){
				System.out.println(111);
				set.remove(e);
				e.setCompany(null);
				session.delete(e);
			}
		}
		session.beginTransaction().commit();
	}

异常信息如：


Exception in thread "main" java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
	at java.util.HashMap$KeyIterator.next(Unknown Source)
	at org.hibernate.collection.AbstractPersistentCollection$IteratorProxy.next(AbstractPersistentCollection.java:555)
	at po.logic.del(logic.java:84)
	at po.logic.main(logic.java:18)

修改办法如下：



public void del(int id){
		session.beginTransaction().begin();
		Company c=(Company) session.get(Company.class, 1);
		Set set=c.getEmployees();
		Iterator it=set.iterator();
		while(it.hasNext()){
			Employee e=(Employee) it.next();
			System.out.println(e.getId());
			System.out.println(id);
			if(e.getId()==id){
				System.out.println(111);
				[color=red][size=xx-large]it.remove();[/size][align=center][/align][/color]
				e.setCompany(null);
				session.delete(e);
			}
		}
		session.beginTransaction().commit();
	}