Java SerialIzation：反序列化对象时出现“ ClassNotFoundException” [英] Java SerialIzation: 'ClassNotFoundException' when deserializing an Object

问题描述

错误：

java.lang.ClassNotFoundException：testprocedure.tp $ 3
位于java.net.URLClassLoader $ 1。 run（未知源）
在java.net.URLClassLoader $ 1.run（未知源）
在java.security.AccessController.doPrivileged（本机方法）
在java.net.URLClassLoader.findClass （未知来源）java.lang.ClassLoader.loadClass上的
（未知来源）sun.misc.Launcher $ AppClassLoader.loadClass（java.lang.ClassLoader.loadClass上的
） （未知来源）java.lang.Class.forName0处的
（本机方法）java.lang.Class.forName处的
（未知源）java.io.ObjectInputStream.resolveClass处的
（未知源）java.io.ObjectInputStream.readNonProxyDesc上的
（未知源）java.io.ObjectInputStream.readClassDesc上的
（未知源）java.io.ObjectInputStream.readOrdinaryObject上的
（未知源） java.io.ObjectInputStream.readOb上的
ject0（未知源）
在java.io.ObjectInputStream.defaultReadFields（未知源）
在java.io.ObjectInputStream.readSerialData（未知源）在Java.io.ObjectInputStream.readOrdinaryObject（未知源）java.io.ObjectInputStream.readObject0处的
（未知源）java.io.ObjectInputStream.readObject处
（未知源）core.ProcedureSetup.load（ProcedureSetup.java： 57）core.Engine.main（Engine.java:25）上的

java.lang.ClassNotFoundException: testprocedure.tp$3 at java.net.URLClassLoader$1.run(Unknown Source) at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Unknown Source) at java.io.ObjectInputStream.resolveClass(Unknown Source) at java.io.ObjectInputStream.readNonProxyDesc(Unknown Source) at java.io.ObjectInputStream.readClassDesc(Unknown Source) at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source) at java.io.ObjectInputStream.readObject0(Unknown Source) at java.io.ObjectInputStream.defaultReadFields(Unknown Source) at java.io.ObjectInputStream.readSerialData(Unknown Source) at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source) at java.io.ObjectInputStream.readObject0(Unknown Source) at java.io.ObjectInputStream.readObject(Unknown Source) at core.ProcedureSetup.load(ProcedureSetup.java:57) at core.Engine.main(Engine.java:25)

我实例化该对象并调用

I instantiate the object and call the "ProcedureSetup"'s "save" method from Class "tp".

ProcedureSetup ps=new ProcedureSetup(new Procedure(){ public void doStuff(){ System.out.println("Stuff is being done"); }});
ps.save();

但是我从具有-ALL-所需代码但 tp

however I load from a different collection of programs that has -ALL- required code but "tp"

ProcedureSetup ps=new ProcedureSetup();
ps.load();

在类内保存和加载对象：

Object saving and loading within class:

public void load(){
    String path=Operator.persistentGetFile();//gets the file path
    ObjectInputStream ois=null;
    FileInputStream fin=null;
    ProcedureSetup temp=null;
    try {
        fin = new FileInputStream(path);
        ois = new ObjectInputStream(fin);
        temp=(ProcedureSetup) ois.readObject();
        ois.close();
        fin.close();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

    if(ois!=null){
        try {
            ois.close();
        } catch (IOException e) {}
    }
    if(fin!=null){
        try {
            fin.close();
        } catch (IOException e) {}
    }
    if(temp!=null){
        a=temp.a;
    }else{
        load();//If a load is failed, restart process.
    }
}

public void save(){
    String path=Operator.persistentGetDirectory();//get directory to save to
        String input =  JOptionPane.showInputDialog(this, "Enter the File name:");
        ObjectOutputStream oos=null;
        FileOutputStream fon=null;
        try {
            fon = new FileOutputStream(path+input+".obj");
            oos = new ObjectOutputStream(fon);
            try {
                oos.writeObject(this);
            } catch (CloneNotSupportedException e) {
                e.printStackTrace();
            }
            oos.close();
            fon.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
            if(oos!=null){
        try {
            oos.close();
        } catch (IOException e) {}
    }
    if(fon!=null){
        try {
            fon.close();
        } catch (IOException e) {}
    }

}

我的问题是：

为什么会发生这些错误？

Why are these errors happening?

为什么（如有必要）我的类路径中是否需要包含 tp？

Why (if necessary) do I need to have "tp" in my classpath?

如果实际上有一种方法可以将对象保存为当前状态而无需使用 tp在类路径中，我将如何去做？ （链接会很可爱）

If there is in fact a way to save the object in its current state with out the necessity of "tp" in the classpath how would I go about doing that? (Links would be lovely)

推荐答案

new Procedure(){ public void doStuff(){ System.out.println("Stuff is being done"); }}

上面是您的 tp 类。因此，要反序列化，此匿名内部类及其封闭类 tp 必须出现在类路径中：字节流包含类名和字段

The above is an anonymous inner class of your tp class. So, to be deserialized, this anonymous inner class, and its enclosing class tp, must be present in the classpath: the stream of bytes contains the name of the class and the fields of the object, but it doesn't contain the byte-code of the class itself.

您应该将其设置为顶级类，或者至少将其设置为 static 内部类。

You should make it a top-level class, or at least a static inner class.

您还应该遵守Java命名约定：类为CamelCased。

You should also respect the Java naming conventions: classes are CamelCased.

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