Using PrintWriter in Java
By: Abinaya Printer Friendly Format
PrintWriter defines several constructors. The one we will use is shown here:
PrintWriter(OutputStream outputStream, boolean flushOnNewline)
Here, outputStream is an object of type OutputStream, and flushOnNewline controls whether Java flushes the output stream every time a newline ('\\n') character is output. If flushOnNewline is true, flushing automatically takes place. If false, flushing is not automatic.
PrintWriter supports the print( ) and println( ) methods for all types including Object. Thus, you can use these methods in the same way as they have been used with System.out. If an argument is not a simple type, the PrintWriter methods call the object's toString( ) method and then print the result.
To write to the console by using a PrintWriter, specify System.out for the output stream and flush the stream after each newline. For example, this line of code creates a PrintWriter that is connected to console output:
PrintWriter pw = new PrintWriter(System.out, true);
The following application illustrates using a PrintWriter to handle console output:
// Demonstrate PrintWriter
import java.io.*;
public class PrintWriterDemo {
public static void main(String args[]) {
PrintWriter pw = new PrintWriter(System.out, true);
pw.println("This is a string");
int i = -7;
pw.println(i);
double d = 4.5e-7;
pw.println(d);
}
}
The output from this program is shown here:
This is a string
-7
4.5E-7
Remember, there is nothing wrong with using System.out to write simple text output to the console when you are learning Java or debugging your programs. However, using a PrintWriter will make your real-world applications easier to internationalize. Because no advantage is gained by using a PrintWriter in the sample programs shown in this book, we will continue to use System.out to write to the console.
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Archived Comments
1. can client use prinwriter?????
View Tutorial By: sujay at 2009-02-20 00:23:33
2. yes. Client needs to use printwriter, especially w
View Tutorial By: Aksh at 2011-07-06 03:30:46
3. can i use PrintWriter to save to a word document o
View Tutorial By: philip at 2013-03-20 10:21:01