Cascade="all-delete-orphan"以及java.util.ConcurrentModificationException问题

最新推荐文章于 2025-12-29 16:24:28 发布

最新推荐文章于 2025-12-29 16:24:28 发布 · 208 阅读

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#Java #Hibernate #XML #.net

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本文探讨了Hibernate中cascade=all-delete-orphan的应用，以及如何在使用Collection或List等集合进行迭代删除操作时避免java.util.ConcurrentModificationException异常。

为以下两个问题提供解决：

1. Hibernate cascade="all-delete-orphan"应用；

2. 用Collection or List 等集合时，迭代remove操作引起的java.util.ConcurrentModificationException问题

	/** 修改業務系統 */
	public String updateBuinessSys() {
		modify = true;
		String transId = (String) getRequestMap().get("transId");
		if (StringUtil.isNullOrBlank(transId)) {
			context.addMessage(null, new FacesMessage("不能獲取業務系統對象"));
			return null;
		}
		Transaction transaction = transactionsManager.getTransactionById(transId);
		if (transaction != null) {
			transaction.setTransName(transName);
			transaction.setTransCode(transCode);
			transaction.setTransDesc(transDesc);
			transaction.setEnterpriseCodes(enterpriseCodes);
			transaction.setBankCodes(bankCodes);

			String transFuncXml = context.getExternalContext().getRequestParameterMap().get("transFuncXml");
			assembleTransFuncs(transFuncXml);

			Set<String> newFunIdSet = new HashSet<String>();//新增的列表id set
			Set<String> dbFunIdSet = new HashSet<String>();//DB中的列表id set
			List<TransFunction> funList = transaction.getTransFunctions();
			for (Iterator iterator = funList.iterator(); iterator.hasNext();) {
				TransFunction fun = (TransFunction) iterator.next();
				dbFunIdSet.add(fun.getId());
			}
			for (Iterator iterator = transFunList.iterator(); iterator.hasNext();) {
				TransFunction fun = (TransFunction) iterator.next();
				if (StringUtil.isNotNullOrBlank(fun.getId())) {
					newFunIdSet.add(fun.getId());
				}
			}
			/* 先remove,後add則不需要判斷fun.id為null的情況 */
			for (Iterator iterator = funList.iterator(); iterator.hasNext();) {
				TransFunction fun = (TransFunction) iterator.next();
				if (!newFunIdSet.contains(fun.getId()))//如果保存的list中的ID在DB中不存在了，即已經被刪除了，則remove from list，使之成為orphan
					//funList.remove(fun); 這一句會引起java.util.ConcurrentModificationException
					iterator.remove();
			}
			for (Iterator iterator = transFunList.iterator(); iterator.hasNext();) {
				TransFunction fun = (TransFunction) iterator.next();
				if (StringUtil.isNullOrBlank(fun.getId()) || !dbFunIdSet.contains(fun.getId()))
					funList.add(fun);//新增的記錄在DB中沒有，則認為是新增的記錄，加入到list當中去
			}

			//transaction.setTransFunctions(transFunList); 不需要重新設置,設定了all-delete-orphan即可
			transactionsManager.saveOrUpdate(transaction);
			return "viewBusinessState";
		}
		context.addMessage(null, new FacesMessage("無效的表單參數"));
		return Constants.ERROR;
	}

Transaction - TransFunction是一对多的关系： hbm.xml配置档如下：

<?xml version="1.0"  encoding='UTF-8'?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
	"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.test.domain">
	<class name="Transaction" table="SYS_TRANS">
		<id name="id" column="ID" length="32" type="string">
			<generator class="uuid" />
		</id>
		<property name="transName" column="NAME" length="30" />
		<property name="transCode" column="CODE" length="10" unique="true" />
		<property name="transDesc" column="DESCR" length="200" />
		<property name="enterpriseCodes" column="ENTP_CODES" length="1000" />
		<property name="bankCodes" column="BANK_CODES" length="1000" />
		<bag name="transFunctions" cascade="all-delete-orphan" inverse="false" lazy="false">
			<key column="TRANS_ID" />
			<one-to-many class="TransFunction" />
		</bag>
	</class>

</hibernate-mapping>

<?xml version="1.0"  encoding='UTF-8'?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
	"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.test.domain">
	<class name="TransFunction" table="SYS_TRANS_FUNC">
		<id name="id" column="ID" length="32" type="string">
			<generator class="uuid" />
		</id>
		<property name="funcName" column="NAME" length="30" />
		<property name="funcCode" column="CODE" length="20" unique="true" />
		<many-to-one name="transaction" column="TRANS_ID"/>
	</class>

</hibernate-mapping>