用于opencmis方法getdescendants的Java OutOfMemoryError (-1)

Question

我的目标是从一个拥有100000个文档的户外站点获取所有文档。我使用的是OpenCmis库。我的问题是，通过这个过程，我得到了一个java.lang.OutOfMemoryError: Java heap space。

站点上所有文档的总大小为:500 is。

代码如下：

CmisObject cmisObject = session.getObjectByPath(path);
FolderImpl sitoFolder = (FolderImpl) cmisObject;
List<Tree<FileableCmisObject>> sitoFolderDescendants = sitoFolder.getDescendants(-1);

这是我的堆栈跟踪错误：

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at java.util.HashMap.newNode(HashMap.java:1742)
at java.util.HashMap.putVal(HashMap.java:630)
at java.util.HashMap.put(HashMap.java:611)
at org.apache.chemistry.opencmis.commons.impl.XMLWalker.handleExtensionLevel(XMLWalker.java:128)
at org.apache.chemistry.opencmis.commons.impl.XMLWalker.handleExtensionLevel(XMLWalker.java:161)
at org.apache.chemistry.opencmis.commons.impl.XMLWalker.handleExtensionLevel(XMLWalker.java:161)
at org.apache.chemistry.opencmis.commons.impl.XMLWalker.handleExtension(XMLWalker.java:112)
at org.apache.chemistry.opencmis.commons.impl.XMLWalker.walk(XMLWalker.java:58)
at org.apache.chemistry.opencmis.commons.impl.XMLConverter$18.read(XMLConverter.java:2198)
at org.apache.chemistry.opencmis.commons.impl.XMLConverter$18.read(XMLConverter.java:2188)
at org.apache.chemistry.opencmis.commons.impl.XMLWalker.walk(XMLWalker.java:56)
at org.apache.chemistry.opencmis.commons.impl.XMLConverter.convertObject(XMLConverter.java:1102)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseElement(AtomPubParser.java:332)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseEntry(AtomPubParser.java:284)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseFeed(AtomPubParser.java:243)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseChildren(AtomPubParser.java:372)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseElement(AtomPubParser.java:339)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseEntry(AtomPubParser.java:284)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseFeed(AtomPubParser.java:243)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseChildren(AtomPubParser.java:372)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseElement(AtomPubParser.java:339)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseEntry(AtomPubParser.java:284)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseFeed(AtomPubParser.java:243)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseChildren(AtomPubParser.java:372)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseElement(AtomPubParser.java:339)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseEntry(AtomPubParser.java:284)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseFeed(AtomPubParser.java:243)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseChildren(AtomPubParser.java:372)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseElement(AtomPubParser.java:339)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseEntry(AtomPubParser.java:284)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parseFeed(AtomPubParser.java:243)
at org.apache.chemistry.opencmis.client.bindings.spi.atompub.AtomPubParser.parse(AtomPubParser.java:109)

Answer 1

不要使用getDescendants(-1)！如果您真的非常需要getDescendants()，请使用仅选择所需属性并关闭允许的操作和ACL的操作上下文。参见http://chemistry.apache.org/docs/cmis-samples/samples/operation-context/index.html。

Answer 2

我不认为在同一时间获得所有节点是一个好主意。

CMIS有几种方法可以对查询进行分页。使用分页，您可以一次检索预定义数量的文档，然后释放内存。

有关示例Apache CMIS: Paging query result，请参阅