Write file with PrintWriter

Posted on December 15, 2012 by justexample

package com.justexample.java.io;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;

public class PrintWriterExample {

	public static void main(String[] args) {

		String filename = "c:" + File.separator + "JustExample.txt";
		File f = new File(filename);
		PrintWriter pw = null;
		try {
			pw = new PrintWriter(f);
			String strContent = "Just Example";
			int intContent = 1;
			double doubleContent = Math.random();
			//convinient way to add new line while print content
			pw.println(strContent);
			//using printf to format content. SInce java 1.5
			pw.printf("Hello this is %s. I am %d years old. My lucky number is  %f", strContent, intContent, doubleContent);
			pw.flush();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}finally{
			//no matter what happen. close the output stream always.
			//note that closing a printer will not throw IOException
			if(pw!=null){
				pw.close();
			}
		}

	}

}

package com.justexample.java.io;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.PrintWriter;

public class PrintWriterExample {

public static void main(String[] args) {

String filename = "c:" + File.separator + "JustExample.txt";

File f = new File(filename);

PrintWriter pw = null;

try {

pw = new PrintWriter(f);

String strContent = "Just Example";

int intContent = 1;

double doubleContent = Math.random();

//convinient way to add new line while print content

pw.println(strContent);

//using printf to format content. SInce java 1.5

pw.printf("Hello this is %s. I am %d years old. My lucky number is %f", strContent, intContent, doubleContent);

pw.flush();

} catch (FileNotFoundException e) {

e.printStackTrace();

}finally{

//no matter what happen. close the output stream always.

//note that closing a printer will not throw IOException

if(pw!=null){

pw.close();

}

Reference
http://docs.oracle.com/javase/1.5.0/docs/api/java/io/PrintWriter.html
http://docs.oracle.com/javase/7/docs/api/java/util/Formatter.html

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Write file with BufferedOutputStream

Posted on December 14, 2012 by justexample

package com.justexample.java.io;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class BufferedOutputStreamExample {

	public static void main(String[] args) {

		String filename = "c:" + File.separator + "JustExample.txt";
		File f = new File(filename);
		FileOutputStream fos = null;
		BufferedOutputStream bos = null;
		try {
			fos = new FileOutputStream(f);
			bos = new BufferedOutputStream(fos);
			String content = "Just Example";
			bos.write(content.getBytes());
			bos.flush();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}finally{
			//no matter what happen. close the output stream always.
			if(bos!=null){
				try {
					bos.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}

	}

}

package com.justexample.java.io;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

public class BufferedOutputStreamExample {

public static void main(String[] args) {

String filename = "c:" + File.separator + "JustExample.txt";

File f = new File(filename);

FileOutputStream fos = null;

BufferedOutputStream bos = null;

try {

fos = new FileOutputStream(f);

bos = new BufferedOutputStream(fos);

String content = "Just Example";

bos.write(content.getBytes());

bos.flush();

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}finally{

//no matter what happen. close the output stream always.

if(bos!=null){

try {

bos.close();

} catch (IOException e) {

e.printStackTrace();

}

Reference
http://download.java.net/jdk7/archive/b123/docs/api/java/io/BufferedOutputStream.html

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Move File

Posted on December 10, 2012 by justexample

Example of move folder/files using Native I/O in java

package com.justexample.java.io;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;

public class MoveFileExample {

	public static void main(String[] args) {
		File fromFolder = new File("C:\\originalFolder");
		File toFolder = new File("C:\\targetFolder");
		//Note : 
		//StandardCopyOption.ATOMIC_MOVE Move the file as an atomic file system operation.
		//StandardCopyOption.REPLACE_EXISTING - Replace an existing file if it exists.
		//StandardCopyOption.COPY_ATTRIBUTES - Copy attributes to the new file.
		try {
			Files.move(fromFolder.toPath(), toFolder.toPath(), 
					StandardCopyOption.ATOMIC_MOVE,
					StandardCopyOption.REPLACE_EXISTING,
					StandardCopyOption.COPY_ATTRIBUTES
					);
			System.out.println("Success");
		} catch (IOException e) {
			System.out.println("Failed");
			e.printStackTrace();
		}

	}

}

package com.justexample.java.io;

import java.io.File;

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.StandardCopyOption;

public class MoveFileExample {

public static void main(String[] args) {

File fromFolder = new File("C:\\originalFolder");

File toFolder = new File("C:\\targetFolder");

//Note :

//StandardCopyOption.ATOMIC_MOVE Move the file as an atomic file system operation.

//StandardCopyOption.REPLACE_EXISTING - Replace an existing file if it exists.

//StandardCopyOption.COPY_ATTRIBUTES - Copy attributes to the new file.

try {

Files.move(fromFolder.toPath(), toFolder.toPath(),

StandardCopyOption.ATOMIC_MOVE,

StandardCopyOption.REPLACE_EXISTING,

StandardCopyOption.COPY_ATTRIBUTES

);

System.out.println("Success");

} catch (IOException e) {

System.out.println("Failed");

e.printStackTrace();

}

Note :
Moving the parent folder will also moving all the child folder inside.

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Rename File

Posted on December 10, 2012 by justexample

Example of rename file in java

package com.justexample.java.io;

import java.io.File;

public class RenameFileExample {

	public static void main(String[] args) {
		File fromFile = new File("C:\\JustExampleOld.txt");
		File toFile = new File("C:\\JustExampleNew.txt");

		if(fromFile.renameTo(toFile)){
			System.out.println("Success.");
		}else{
			System.out.println("Failed");
		}

	}

}

package com.justexample.java.io;

import java.io.File;

public class RenameFileExample {

public static void main(String[] args) {

File fromFile = new File("C:\\JustExampleOld.txt");

File toFile = new File("C:\\JustExampleNew.txt");

if(fromFile.renameTo(toFile)){

System.out.println("Success.");

}else{

System.out.println("Failed");

}

Reference
http://docs.oracle.com/javase/7/docs/api/java/io/File.html#renameTo(java.io.File)

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Write file with FileOutputStream

Posted on December 9, 2012 by justexample

package com.justexample.java.io;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class WriteStringFileExample {

	public static void main(String[] args) {

		String filename = "c:" + File.separator + "StringExample.txt";
		File f = new File(filename);
		FileOutputStream fos = null;
		try {
			fos = new FileOutputStream(f);
			String content = "Just Example";
			fos.write(content.getBytes());
			fos.flush();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}finally{
			//no matter what happen. close the output stream always.
			if(fos!=null){
				try {
					fos.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}

	}

}

package com.justexample.java.io;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

public class WriteStringFileExample {

public static void main(String[] args) {

String filename = "c:" + File.separator + "StringExample.txt";

File f = new File(filename);

FileOutputStream fos = null;

try {

fos = new FileOutputStream(f);

String content = "Just Example";

fos.write(content.getBytes());

fos.flush();

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}finally{

//no matter what happen. close the output stream always.

if(fos!=null){

try {

fos.close();

} catch (IOException e) {

e.printStackTrace();

}

Reference
http://docs.oracle.com/javase/6/docs/api/java/io/FileOutputStream.html#write(byte[])

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Delete File

Posted on December 9, 2012 by justexample

package com.justexample.java.io;

import java.io.File;

public class DeleteFileExample {

	public static void main(String[] args) {

		try {
			File file = new File("c:\\DeleteExample.txt");

			if(file.delete()){
				System.out.println(file.getName() + " deleted!");
			}else{
				System.out.println("Failed.");
			}
		} catch (Exception e) {
			e.printStackTrace();
		}

	}

}

package com.justexample.java.io;

import java.io.File;

public class DeleteFileExample {

public static void main(String[] args) {

try {

File file = new File("c:\\DeleteExample.txt");

if(file.delete()){

System.out.println(file.getName() + " deleted!");

}else{

System.out.println("Failed.");

}

} catch (Exception e) {

e.printStackTrace();

}

Reference
http://docs.oracle.com/javase/6/docs/api/java/io/File.html#delete()

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Create New File

Posted on December 9, 2012 by justexample

package com.justexample.java.io;

import java.io.File;
import java.io.IOException;

public class CreateFileExample {

	public static void main(String argsp[]){
		try {
		      File file = new File("JustExampleFile.txt");
		      if (file.createNewFile()){
		        System.out.println("File created successfully!");
		      }else{
		        System.out.println("Failed.");
		      }

	    	} catch (IOException e) {
		      e.printStackTrace();
		}
	}
}

package com.justexample.java.io;

import java.io.File;

import java.io.IOException;

public class CreateFileExample {

public static void main(String argsp[]){

try {

File file = new File("JustExampleFile.txt");

if (file.createNewFile()){

System.out.println("File created successfully!");

}else{

System.out.println("Failed.");

}

} catch (IOException e) {

e.printStackTrace();

}

Reference
http://docs.oracle.com/javase/6/docs/api/java/io/File.html#createNewFile()

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Just Example

Learn by Example

Category Archives: Java I/O

Write file with PrintWriter

Write file with BufferedOutputStream

Move File

Rename File

Write file with FileOutputStream

Delete File

Create New File