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将环环形天体树-Stacack OverflowError-需要定制序列编码
原标题：Serialize cyclic object tree – StackOverflowError – custom serialization code needed

I am making an android app where I have a bidirectional cyclic object tree that I need to serialize to fill in a blob field in a Sqlite database. But the default serialization implementation throws a StackOverflowError at me (stack trace at the bottom). But I have no experience in writing custom java serialization code to avoid this situation.

我这个线索 (< a href=>"https://stackoverflow.com/ questions/4388775/stackoverflowror- when-sergize-an-object-in-java" > stackOverflowError) 在将一个物体在 Java 中序列时, 他谈论了这个问题, 但对于我的情况我还不知道如何实施:

It s possible to define a writeObject() method for such a list class that, when the first link is serialized, simply walks the list and serializes each link iteratively; this will prevent the default recursive mechanism from being used.

This is my object model(look at the 1/M, not the other signs): enter image description here

这是我用来将对象模型序列成字节阵列(不太重要)的方法:

public byte[] serialize(Object object) {
        byte[] buf = null;
        try {
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ObjectOutput out = new ObjectOutputStream(bos);
            out.writeObject(object);
            out.close();
            buf = bos.toByteArray();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return buf;
    }

自定义序列函数 :

private void writeObject(java.io.ObjectOutputStream out) throws IOException {
    //please help me with this code
}
private void readObject(java.io.ObjectInputStream in) throws IOException, ClassNotFoundException {
    //please help me with this code
}

希望有人帮助我解决这个问题。任何线索都感激不尽。

例外堆栈跟踪 :

05-25 20:28:16.231: E/AndroidRuntime(14451): FATAL EXCEPTION: main
05-25 20:28:16.231: E/AndroidRuntime(14451): java.lang.StackOverflowError
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.util.IdentityHashMap.findIndex(IdentityHashMap.java:419)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.util.IdentityHashMap.get(IdentityHashMap.java:371)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.dumpCycle(ObjectOutputStream.java:471)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1739)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1689)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1653)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeFieldValues(ObjectOutputStream.java:1143)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:413)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1241)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1575)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1847)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1689)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1653)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeFieldValues(ObjectOutputStream.java:1143)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:413)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1241)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1575)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1847)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1689)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1653)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.util.ArrayList.writeObject(ArrayList.java:651)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.lang.reflect.Method.invokeNative(Native Method)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.lang.reflect.Method.invoke(Method.java:507)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1219)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1575)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1847)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1689)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1653)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeFieldValues(ObjectOutputStream.java:1143)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:413)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1241)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1575)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1847)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1689)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1653)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeFieldValues(ObjectOutputStream.java:1143)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:413)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1241)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1575)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1847)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1689)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1653)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.util.ArrayList.writeObject(ArrayList.java:651)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.lang.reflect.Method.invokeNative(Native Method)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.lang.reflect.Method.invoke(Method.java:507)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1219)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1575)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1847)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1689)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1653)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeFieldValues(ObjectOutputStream.java:1143)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:413)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1241)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1575)
05-25 20:28:16.231: E/AndroidRuntime(14451):    at java.io.ObjectOutputStream.writeObject
最佳回答

Java 序列处理正确处理环形图, 但长列表是个问题 。

如果我理解正确的话, 您的问题与您链接的文章中的问题有点不同, 导致该文章在谈论链接列表时没有正确写入Object 。 而您目前使用 orrayLists, 后者已经将对象存储为平坦的数组, 并且还有一个正确的写对象 。

然而,如果我说对了, 发生的事情或多或少是这样:

你开始对对象A进行序列化, 在它遇到一个长长的序列化列表时, 取第一个元素, 并序列化对象B, 对象B 也有一个长的列表, 它取第一个元素, 再说一遍, 因为它已经被序列化了, 跳过 A, 所以它不会无休止地循环, 但是它会进入一个无休止的循环中, 然后转到 B 列表中的第二个对象, 即 C, C 也有一个长的列表, 前两个元素是 A 和 B, 因此被跳过, 第三个元素是 D, 同时也有一个列表... 和soooo 。

由于这些步骤中的每一步都是堆叠层中的几行,它就填满了,即使它们都是有正确写法的阵列列表。

如果这些列表比起您拥有的运行时间, 缩放成相对的“ 大” 数字, 就可能出现这种情况。 这就是为什么我在评论中询问。 也许可以找到一个解决办法,避免将一些列表(让它们具有短暂性)序列化,并在“ 部分” 的分解后重建它们。

时间：2012-05-25 19:41:17
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