java - 将较大尺寸的对象写入文件时出现 Stackoverflow 错误

Question

当我提供较小尺寸的输入文件时，没有错误。但是，当提供较大尺寸的输入文件时，我收到错误。我正在为该输入文件创建一个树对象，然后我想将该对象保存到文件中。该文件将被创建，稍后写入时会出现错误。

有人知道如何使用将更大的对象写入文件吗ObjectOutputStream？

try{
  JOptionPane.showMessageDialog(null,"in try");
  FileOutputStream fout = new FileOutputStream("d://obj.ser");
  JOptionPane.showMessageDialog(null,"obj created");
  ObjectOutputStream foos = new ObjectOutputStream(fout);  
  JOptionPane.showMessageDialog(null,"oos created");  //till here i get output

  foos.writeObject(tree);
  JOptionPane.showMessageDialog(null,"here compltes writeobj");
  foos.flush();
  JOptionPane.showMessageDialog(null,"after flush");
  //foos.close();
  fout.close();
  JOptionPane.showMessageDialog(null,"alll");


}catch(Exception ex){
  JOptionPane.showMessageDialog(null,"error");
}

树文件是:

    import java.io.BufferedWriter;
    import java.io.FileWriter;
    import java.io.IOException;
    import java.io.Serializable;
    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.Comparator;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    import javax.swing.JTextArea;

    /**
         * This is an implementation of a MISTree (which is modified from a fptree).
    * 
    * 
    */
        public class MISTree implements Serializable {
       // List of items in the header table
           private static final long serialVersionUID = 5950169519310163575L;
       List<Integer> headerList = null;
      // List of pairs (item, node) of the header table
     Map<Integer, MISNode> mapItemNodes = new HashMap<Integer, MISNode>();

      // root of the tree
        MISNode root = new MISNode(); // null node

      /**
       * Constructor
        */
       MISTree() {

       }

    /**
        * Method for adding a transaction to the fp-tree (for the initial
       * construction of the FP-Tree).
       * 
      * @param transaction
    */
      public void addTransaction(List<Integer> transaction) {
     MISNode currentNode = root;
      // For each item in the transaction
    for (Integer item : transaction) {
                    // System.out.println("item in this transaction is "+item);
        // look if there is a node already in the FP-Tree
        MISNode child = currentNode.getChildWithID(item);
        if (child == null) {
            // there is no node, we create a new one
             MISNode newNode = new MISNode();
            newNode.itemID = item;
            newNode.parent = currentNode;
             // we link the new node to its parrent
            currentNode.childs.add(newNode);

             // we take this node as the current node for the next for loop
            // iteration
            currentNode = newNode;

            // We update the header table.
             // We check if there is already a node with this id in the
            // header table
            MISNode headernode = mapItemNodes.get(item);
            if (headernode == null) { // there is not
                mapItemNodes.put(item, newNode);
             } else { // there is
                    // we find the last node with this  id.
                while (headernode.nodeLink != null) {
                    headernode = headernode.nodeLink;
                }
                headernode.nodeLink = newNode;
            }
        } else {
            // there is a node already, we update it
            child.counter++;
            currentNode = child;
         }
    }
}

// here some other methods like to print a tree and other are there
 }

MIS节点也已序列化。对于较小的树来说它效果很好。没有错误，但对于较大尺寸的树，它会给出错误

错误是这样的:

    Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
    at java.lang.Exception.<init>(Unknown Source)
    at java.lang.reflect.InvocationTargetException.<init>(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)
    at java.util.ArrayList.writeObject(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)
    at java.util.ArrayList.writeObject(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)
    at java.util.ArrayList.writeObject(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)
    at java.util.ArrayList.writeObject(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)
    at java.util.ArrayList.writeObject(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)
    at java.util.ArrayList.writeObject(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)
    at java.util.ArrayList.writeObject(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)
    at java.util.ArrayList.writeObject(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)
    at java.util.ArrayList.writeObject(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)

Answer 1

我感觉问题出在你的树结构上。 ObjectOutputStream 通过序列化对象来工作，当序列化一个对象时，默认情况下该对象的所有成员都会被序列化(除了某些边缘情况)，这意味着如果您有一个深度嵌套的树，每个成员都会被序列化。树中的级别将意味着对序列化函数的更多调用。 (我不认为循环引用是问题的一部分，因为 Java 的序列化器会跟踪反向引用，但这可能只适用于已经序列化的对象，而不适用于序列化过程中的对象，因此您可能需要检查一下也是。)

我建议以某种方式展平树并单独编写对象，而不是尝试将整个树编写为一个对象。然后，当您使用 ObjectInputStream 读取对象时，从展平的对象重建树。