- 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 - DataOutputStream writeInt(int value)
Description
The Java DataOuputStream writeInt(int v) method writes a int value to the to the underlying stream as four bytes. The counter written is incremented by 4 on successful invocation of this method.
Declaration
Following is the declaration for java.io.DataOutputStream.writeInt(int v) method −
public final void writeInt(int v)
Parameters
v − an int value to be written to the output stream.
Return Value
This method does not return any value.
Exception
IOException − If an I/O error occurs.
Example 1
The following example shows the usage of Java DataInputStream writeInt(int value) method. We've created InputStream, DataInputStream, FileOutputStream and DataOutputStream reference. A int[] buf is initialized with some int values. A FileOutputStream object is created with a File. Then DataOutputStream is initialized with FileOutputStream object created before. Then int array is iterated to write int values using writeInt() method to the dataoutputstream.
Once int arrays is fully written into the stream, we've flush the stream to store the values in the file. Now using FileInputStream and DataInputStream, we're reading the file written earlier. Now we're checking if DataInputStream object has data using available() method. Then using readInt() method, we're reading every value as int. Finally we're closing all the streams.
import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; public class DataOutputStreamDemo { public static void main(String[] args) throws IOException { InputStream is = null; DataInputStream dis = null; FileOutputStream fos = null; DataOutputStream dos = null; int[] dbuf = {65,66,67,68,69,70}; try { // create file output stream fos = new FileOutputStream("F:\\test.txt"); // create data output stream dos = new DataOutputStream(fos); // for each byte in the buffer for (int d:dbuf) { // write int to the data output stream dos.writeInt(d); } // force bytes to the underlying stream dos.flush(); // create file input stream is = new FileInputStream("F:\\test.txt"); // create new data input stream dis = new DataInputStream(is); // read till end of the stream while(dis.available()>0) { // read int int c = dis.readInt(); // print System.out.print(c + " "); } } catch(Exception e) { // if any I/O error occurs e.printStackTrace(); } finally { // releases all system resources from the streams if(is!=null) is.close(); if(dos!=null) is.close(); if(dis!=null) dis.close(); if(fos!=null) fos.close(); } } }
Output
Let us compile and run the above program, this will produce the following result −
65 66 67 68 69 70
Example 2
The following example shows the usage of Java DataInputStream writeInt(int value) method. We've created InputStream, DataInputStream, FileOutputStream and DataOutputStream reference. A int[] buf is initialized with some int values. A FileOutputStream object is created with a File. Then DataOutputStream is initialized with FileOutputStream object created before. As a special case, we're closing the stream before writing any value to check if it supports writing values after closing it.
Then int array is iterated to write int values using writeInt() method to the dataoutputstream. Once int arrays is fully written into the stream, we've flush the stream to store the values in the file. Now using FileInputStream and DataInputStream, we're reading the file written earlier. Now we're checking if DataInputStream object has data using available() method. Then using readInt() method, we're reading every value as int. Finally we're closing all the streams.
import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; public class DataOutputStreamDemo { public static void main(String[] args) throws IOException { InputStream is = null; DataInputStream dis = null; FileOutputStream fos = null; DataOutputStream dos = null; int[] dbuf = {65,66,67,68,69,70}; try { // create file output stream fos = new FileOutputStream("F:\\test.txt"); // create data output stream dos = new DataOutputStream(fos); // close the stream dos.close(); // for each byte in the buffer for (int d:dbuf) { // write int to the data output stream dos.writeInt(d); } // force bytes to the underlying stream dos.flush(); // create file input stream is = new FileInputStream("F:\\test.txt"); // create new data input stream dis = new DataInputStream(is); // read till end of the stream while(dis.available()>0) { // read int int c = dis.readInt(); // print System.out.print(c + " "); } } catch(Exception e) { // if any I/O error occurs e.printStackTrace(); } finally { // releases all system resources from the streams if(is!=null) is.close(); if(dos!=null) is.close(); if(dis!=null) dis.close(); if(fos!=null) fos.close(); } } }
Output
Let us compile and run the above program, this will produce the following result −
java.io.IOException: Stream Closed at java.base/java.io.FileOutputStream.write(Native Method) at java.base/java.io.FileOutputStream.write(FileOutputStream.java:318) at java.base/java.io.DataOutputStream.writeInt(DataOutputStream.java:197) at DataOutputStreamDemo.main(DataOutputStreamDemo.java:30) Exception in thread "main" java.lang.NullPointerException at DataOutputStreamDemo.main(DataOutputStreamDemo.java:60)uu
As underlying stream FileOutputStream is not supporting write to stream after closing it, we get exception in program execution.