Question

预先感谢您的回复。我试图将对象的ArrayList保存到文件，但不断获得IOExeption。代码：

public static final String FILE_PATH=""; // is set to blank for tests. It DOES create a file.

public static void saveToFileCl(ArrayList<cliente> al ) {
    if (al != null ) {
        try {
            FileOutputStream  file = new FileOutputStream(FILE_PATH+"cliente.dat");
            ObjectOutputStream outStream = new ObjectOutputStream(file);
            outStream.writeInt(cliente.getAuto_inc()); // works fine
            outStream.writeObject(new Date()); // works fine - not needed just for testing!
            outStream.writeObject(al); // exception !!!!
            outStream.flush();
            outStream.close();
        } catch (IOException e) {System.out.println("Erro a gravar ficheiro de clientes!\n"+e.getCause());}
          catch (Exception e) {System.out.println("Erro a desconhecido ao gravar ficheiro de clientes!\n"+e.getMessage());}
    }    
}

有没有人可以告诉我为什么会有例外？

Answer 1

要将实例写入带有OutputStream.writeObject(Object)的OutputStream，您需要实例为Serializable。这是一个接口（java.io.Serializable），它告诉实例可以以字节形式存储。

您只需要将接口添加到类

class MyClass implements java.io.Serializable { ... }

没有方法可以实现，只需这一行即可。

ObjectOutputStream对带有ArrayList对象的writeObject的ioexception

1 个答案: