Java：如何通过从mongodb（远程服务器）读取数据来加速JTree重建？
基本上 mongodb 存储每个节点用户对象（NodePro）和parentId。
此类通过查询给定parentId 的所有子级递归地构建Jtree。
问题是，在处理一棵树的数百或数千个节点时，我必须等待长达 5 分钟才能加载整个树。
有没有办法显着加快速度？目前，即使处理不到一百个节点，树也需要很长时间才能完成。
public class BuildTree {
public BuildTree(DefaultMutableTreeNode treeNode){
DefaultMutableTreeNode aParentNode = treeNode;
try {
processChildren(aParentNode);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void processChildren(DefaultMutableTreeNode parentNode) throws Exception{
NodePro np = (NodePro) parentNode.getUserObject();
List<NodePro> nodelist = NodeDAO.getInstance().getChildrenOfParent(np.getId().toString());
if (nodelist.isEmpty()){
System.out.println("empty");
return;
}else{
for (int i=0; i< nodelist.size(); i++)
{
NodePro childnode = nodelist.get(i);
DefaultMutableTreeNode child = new DefaultMutableTreeNode(childnode);
TreeModel.getInstance().insertNodeInto(child,parentNode,TreeModel.getInstance().getChildCount(parentNode));
DefaultMutableTreeNode parent = (DefaultMutableTreeNode)
TreeModel.getInstance().getChild(parentNode, i);
processChildren(parent);
}
return;
}
}
basically mongodb stores each node userobject(NodePro) with parentId.
This class recursively builds a Jtree from querying all the children of a given parentId.
The problem is I have to wait up to 5 minutes for the entire tree to load when dealing with hundreds or thousands of nodes of a single tree.
Is there a way to speed this up significantly? currently even dealing with under hundred nodes, it will take a long time for the tree to become complete.
public class BuildTree {
public BuildTree(DefaultMutableTreeNode treeNode){
DefaultMutableTreeNode aParentNode = treeNode;
try {
processChildren(aParentNode);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void processChildren(DefaultMutableTreeNode parentNode) throws Exception{
NodePro np = (NodePro) parentNode.getUserObject();
List<NodePro> nodelist = NodeDAO.getInstance().getChildrenOfParent(np.getId().toString());
if (nodelist.isEmpty()){
System.out.println("empty");
return;
}else{
for (int i=0; i< nodelist.size(); i++)
{
NodePro childnode = nodelist.get(i);
DefaultMutableTreeNode child = new DefaultMutableTreeNode(childnode);
TreeModel.getInstance().insertNodeInto(child,parentNode,TreeModel.getInstance().getChildCount(parentNode));
DefaultMutableTreeNode parent = (DefaultMutableTreeNode)
TreeModel.getInstance().getChild(parentNode, i);
processChildren(parent);
}
return;
}
}
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评论（2）
@trashgod 的评论是正确的：代码把时间花在哪里了？是在对象创建中吗？当您需要创建数千个节点时，
DefaultMutableTreeNode的性能不佳。是在从MongoDB检索节点信息的过程中吗？如果您无法加快树的创建速度，您将需要研究延迟加载节点的子节点。也就是说，在用户请求查看子节点之前不要加载节点。
其他可能性是在后台线程中加载子节点。
但是，与任何性能改进工作一样，您需要测量代码的哪一部分速度较慢，然后找出改进方法。
@trashgod is right in his comment: where is the code spending its time? Is it in the object creation?
DefaultMutableTreeNodedoesn't perform well when you've got thousands of node to create. Is it during retrieval of the node information from MongoDB?If you can't speed up the creation of the tree, you'll want to investigate lazily-loading the children of a node. That is, don't load the node until the user requests to see the children.
Other possibilities are to load the children nodes in a background thread.
However, like any performance improvement work, you need to measure which part of your code is slow and then figure out how to improve it.
这将是评论，但
删除主题中的
MongoDb 引擎，这与您的问题（以及您的帖子数量）无关，存在三个区域
1/ 您不熟悉（摘要/默认） )
TreeModel正确且正确的方法，创建JTree及其Model一次，而不是像您显示的那样，然后严格分离 SwingJComponets和业务逻辑（加载/更改/管理/保存/使用 SwingJComponents的数据进行任何操作），您可以为任何操作2/ 问题创建新的
void()< a href="http://download.oracle.com/javase/tutorial/uiswing/concurrency/index.html" rel="nofollow noreferrer">Swing 中的并发，因为从/到的任何内容数据库基本上是 BackGroung 任务，任何内容都必须包装到invokeLater()中，并且有自定义 Java 外观和感觉，然后进入invokeAndWait()3 / 扩展为 @trashgod 和 @StanislavL 正确建议仔细阅读此 关于未封闭的 JDBC 对象的帖子
that would be comment but
remove enless
MongoDb enginein your topics, that nothing to do with your issue (and for number of your posts)there are three areas
1/ you are not familair with (Abstract/Default)
TreeModelcorrect and proper way, createJTreeand itsModelonce, not as you displayed, then strictly separeted SwingJComponetsand Bussines Logics (load/change/manage/save/whatever with data for SwingJComponents), your create newvoid()for any of your action2/ issues with Concurency in Swing, bacause anything from/to database is basically BackGroung Task, anything must be wrappef into
invokeLater()and is is thereCustom Java Look and Feelthen intoinvokeAndWait()3/ expands as @trashgod and @StanislavL correctly suggested carefully reads this post about unclosed
JDBC Objects