- Java.io package classes
- Java.io - Home
- Java.io - BufferedInputStream
- Java.io - BufferedOutputStream
- Java.io - BufferedReader
- Java.io - BufferedWriter
- Java.io - ByteArrayInputStream
- Java.io - ByteArrayOutputStream
- Java.io - CharArrayReader
- Java.io - CharArrayWriter
- Java.io - Console
- Java.io - DataInputStream
- Java.io - DataOutputStream
- Java.io - File
- Java.io - FileDescriptor
- Java.io - FileInputStream
- Java.io - FileOutputStream
- Java.io - FilePermission
- Java.io - FileReader
- Java.io - FileWriter
- Java.io - FilterInputStream
- Java.io - FilterOutputStream
- Java.io - FilterReader
- Java.io - FilterWriter
- Java.io - InputStream
- Java.io - InputStreamReader
- Java.io - LineNumberInputStream
- Java.io - LineNumberReader
- Java.io - ObjectInputStream
- Java.io - ObjectInputStream.GetField
- Java.io - ObjectOutputStream
- io - ObjectOutputStream.PutField
- Java.io - ObjectStreamClass
- Java.io - ObjectStreamField
- Java.io - OutputStream
- Java.io - OutputStreamWriter
- Java.io - PipedInputStream
- Java.io - PipedOutputStream
- Java.io - PipedReader
- Java.io - PipedWriter
- Java.io - PrintStream
- Java.io - PrintWriter
- Java.io - PushbackInputStream
- Java.io - PushbackReader
- Java.io - RandomAccessFile
- Java.io - Reader
- Java.io - SequenceInputStream
- Java.io - SerializablePermission
- Java.io - StreamTokenizer
- Java.io - StringBufferInputStream
- Java.io - StringReader
- Java.io - StringWriter
- Java.io - Writer
- Java.io package extras
- Java.io - Interfaces
- Java.io - Exceptions
- Java.io package Useful Resources
- Java.io - Discussion
Java.io.ObjectInputStream.readFields() Method
Description
The java.io.ObjectInputStream.readFields() method reads the persistent fields from the stream and makes them available by name.
Declaration
Following is the declaration for java.io.ObjectInputStream.readFields() method.
public ObjectInputStream.GetField readFields()
Parameters
NA
Return Value
google.grThis method returns the GetField object representing the persistent fields of the object being deserialized.
Exception
ClassNotFoundException − If the class of a serialized object could not be found.
IOException − If an I/O error has occurred.
NotActiveException − If the stream is not currently reading objects.
Example
The following example shows the usage of java.io.ObjectInputStream.readFields() method.
package com.tutorialspoint; import java.io.*; public class ObjectInputStreamDemo { public static void main(String[] args) { try { // create a new file with an ObjectOutputStream FileOutputStream out = new FileOutputStream("test.txt"); ObjectOutputStream oout = new ObjectOutputStream(out); // write something in the file oout.writeObject(new Example()); oout.flush(); // create an ObjectInputStream for the file we created before ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test.txt")); // read the object and print the string Example a = (Example) ois.readObject(); // print the string that is in Example class System.out.println("" + a.s); } catch (Exception ex) { ex.printStackTrace(); } } static class Example implements Serializable { String s = "Hello World!"; private String readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { // call readFields in readObject ObjectInputStream.GetField gf = in.readFields(); // save the string and return it return (String) gf.get("s", null); } } }
Let us compile and run the above program, this will produce the following result −
Hello World!
java_io_objectinputstream.htm
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