Java持久性内存泄漏 [英] java persistance memory leaks

问题描述

我在mysql表中有1M行，当我执行以下代码时，我是java持久性api，然后出现Java堆错误:

I have 1M rows in a mysql table and I am java persistence api when I execute following code then I get java heap error:

int counter = 0;
while (counter < 1000000) {
   java.util.Collection<MyEntityClass> data = myQuery.setFirstResult(counter)
       .setMaxResults(1000).getResultList();
   for(MyEntityClass obj : data){
       System.out.println(obj);
   }
   counter += 1000;
}

推荐答案

当您单击下一步"时，我想知道JTable是否真的挂在了所有那些旧引用上.我不认为这是一个持久性问题.无论JTable背后有什么支持的数据结构，在添加下一批记录之前，我都必须确保已清除它.这样，旧值就可以进行GC处理了.

I'd wonder if JTable is really hanging onto all those old references when you click "next". I don't believe it's a persistence problem. Whatever backing data structure you have behind the JTable, I'd make sure that I cleared it before adding the next batch of records. That way the old values can be GC'd.

您的JTable不应具有ResultSet.最好有一个持久层，从客户那里隐藏这样的细节.查询一批值(不是整个数据集的 )，将其从ResultSet加载到数据结构中，然后在finally块中关闭ResultSet和Statement.您需要在创建它们的方法范围内关闭这些资源，否则您将遇到麻烦.

Your JTable shouldn't have a ResultSet. It'd be better to have a persistence tier that hid such details from clients. Make the query for a batch of values (not the entire data set), load it from the ResultSet into a data structure, and close the ResultSet and Statement in a finally block. You need to close those resources in the scope of the method in which they were created or you're asking for trouble.

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