Java IO Tutorial - Java ObjectInputStream .readObject ()

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Syntax

ObjectInputStream.readObject() has the following syntax.

public final Object readObject()   throws IOException ,     ClassNotFoundException

Example

In the following code shows how to use ObjectInputStream.readObject() method.

//from  w w w.  j a va  2s  .  c o  m
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class Main {

  public static void main(String[] args) throws Exception {

    String s = "Hello World from java2s.com";
    byte[] b = { 'e', 'x', 'a', 'm', 'p', 'l', 'e' };

    FileOutputStream out = new FileOutputStream("test.txt");
    ObjectOutputStream oout = new ObjectOutputStream(out);

    // write something in the file
    oout.writeObject(s);
    oout.writeObject(b);
    oout.flush();
    oout.close();
    // create an ObjectInputStream for the file we created before
    ObjectInputStream ois = new ObjectInputStream(new FileInputStream(
        "test.txt"));

    // read and print an object and cast it as string
    System.out.println((String) ois.readObject());

    // read and print an object and cast it as string
    byte[] read = (byte[]) ois.readObject();
    String s2 = new String(read);
    System.out.println(s2);
    ois.close();
  }
}

The code above generates the following result.

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