Reading serialized object from a file?

Question

I want to write and read a serializable class from a object file. I can write this object to a file but I cannot seem to be able to read the object back in and write it to the console.

Neither one of these options works. I just want to read in the object as it was written to the object file.

Code Tried:

public void readBinary1() throws IOException, ClassNotFoundException {
        ObjectInputStream input = new ObjectInputStream(new FileInputStream
                                      ("G:\\testobject.tmp"));
        input.readObject();

        System.out.println(new myClass());
    }

    public void readBinary1() throws IOException, ClassNotFoundException {
        ObjectInputStream input = new ObjectInputStream(new FileInputStream
                                      ("G:\\testobject.tmp"));

        System.out.println(new myClass(input.readObject()));
    }

class:

class myClass implements Serializable {
    myClass() {}

    myClass(myClass b) {
       this.a = b.a;
       this.b = b.b;
    }

    private static final long serialVersionUID = 1L;
    private int a = 0;
    private int b = 100;
    private transient int c = 50;
}

Code Added:

    I had to add a toString to my class to do it the way that it was suggested to do. That seems to be the way that is easiest in the short run but I would rather write the object and then be able to read in the object with out having to use the toString. Is there a way that I can read in the object with one read and then be able to break the info apart with the .dot notation. Such as mc.variable1 and mc.variable2 and so on. I had to type cast the read object also before the code would compile.

There are couple of input and output streams that allow for the serialization of objects to a file. I am certain that there are different ways to wrap the classes for the read and was wondering also which way was the best way to create the read.

Try searching for this problem on stack overflow -- there are literally dozens of similar questions and answers. — Software Engineer, Feb 17 '14 at 22:37
see http://stackoverflow.com/questions/17293991/how-to-write-and-read-java-serialized-objects-into-a-file — michael, Feb 17 '14 at 22:39
You don't seem to understand you're reading a *serialized object* from the stream. `MyClass mc = (MyClass) input.readObject();`. Done. — Brian Roach, Feb 17 '14 at 22:40
And see http://docs.oracle.com/javase/tutorial/essential/io/objectstreams.html — michael, Feb 17 '14 at 22:40
I know that I am reading a serialized object. I think that it reads the whole object into the variable and then I have to break that information up into what I would want to do with it like write or print or whatever. If I read an object from a file it should read it all in at one time just like if I was reading one string from the file. It would read a string at a time. — Doug Hauf, Feb 17 '14 at 22:51

score 1 · Accepted Answer · answered Feb 17 '14 at 22:40

1

Do this:

myClass readedObject = (myClass) input.readObject();
System.out.println(readedObject);

answered Feb 17 '14 at 22:40

Luis Alves

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Reading serialized object from a file?

1 Answers1