Files copy() Method in Java with Examples – GeeksforGeeks

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The copy() method of java.nio.file.Files Class is used to copy bytes from a file to I/O streams or from I/O streams to a file. I/O Stream means an input source or output destination representing different types of sources e.g. disk files.

Methods: Based on the type of arguments passed, the Files class provides 3 types of copy() method.

  1. Using copy(InputStream in, Path target, CopyOption… options) Method
  2. Using copy(Path source, OutputStream out) Method
  3. Using copy(Path source, Path target, CopyOption… options) Method

Method 1: Using copy(InputStream in, Path target, CopyOption… options) Method

 This method is used to copy all bytes from an input stream to a file.

Parameters:

  • in: The input stream whose the data will be copied
  • target: The path of the file where data will be copied
  • options: Options describing the ways in which the data will be copied

Return Type: Number of copied bytes

Exceptions:

  • IOException: If while reading or writing an error occurred
  • FileAlreadyExistsException: If the target file already exists and can not be replaced
  • DirectoryNotEmptyException: If the target file can not be replaced because it is a non-empty directory
  • UnsupportedOperationException: If the way of copying described by an option is not supported
  • SecurityException: If the write access to the target file is denied by the security manager

Implementation:

Example

Tóm Tắt

Java




import java.io.ByteArrayInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.nio.file.StandardCopyOption;

 

public class GFG {

 

    

    public static void main(String[] args)

    {

        

        String text = "geeksforgeeks";

 

        

        Path path = (Path)Paths.get("/usr", "local", "bin",

                                    "fileIn.txt");

 

        System.out.println("Path of target file: "

                           + path.toString());

 

        

        InputStream in

            = new ByteArrayInputStream(text.getBytes());

 

        

        try {

 

            

            System.out.println(

                "Number of bytes copied: "

                + Files.copy(

                    in, path,

                    StandardCopyOption.REPLACE_EXISTING));

        }

 

        

        catch (IOException e) {

 

            

            e.printStackTrace();

        }

    }

}







 Output:


Path of target file: /usr/local/bin/fileIn.txt
Number of bytes copied: 13


Method 2: Using copy(Path source, OutputStream out) Method


This method is used to copy all bytes from a file to an output stream. 




Parameters: It takes two namely 


    

  • source: The path of the file whose data will be copied
    • 

  • out: The output stream where the copied data will be written
    • 



Return Type: Number of copied bytes


Exceptions: 


    

  • IOException: If while reading or writing an error occurred
    • 

  • SecurityException: If the read access to the target file is denied by the security manager 
    • 



Implementation:


Example


Java























import java.io.ByteArrayOutputStream;


import java.io.IOException;


import java.io.OutputStream;


import java.nio.file.Files;


import java.nio.file.Path;


import java.nio.file.Paths;


 




public class GFG {


 


    


    public static void main(String[] args)


    {


 


        


        Path path = (Path)Paths.get("/usr", "local", "bin",


                                    "fileOut.txt");


 


        


        System.out.println("Path of source file: "


                           + path.toString());


 


        


        OutputStream out = new ByteArrayOutputStream();


 


        


        try {


            


            System.out.println("Number of bytes copied: "


                               + Files.copy(path, out));


        }


 


        


        catch (IOException e) {


 


            


            e.printStackTrace();


        }


    }


}












 Output:


Path of source file: /usr/local/bin/fileOut.txt
Number of bytes copied: 13


 Method 3: Using copy(Path source, Path target, CopyOption… options) Method


This method is used to copy a file to a target file.


Parameters:




    

  • source: The path of the file whose data will be copied
    • 

  • target: The path of the file where data will be copied
    • 

  • options: Options describing the ways in which the data will be copied
    • 



 Return Type: The path to the file where data is copied


Exceptions: 


    

  • IOException: If while reading or writing an error occurred
    • 

  • FileAlreadyExistsException: If the target file already exists and can not be replaced
    • 

  • DirectoryNotEmptyException: If the target file can not be replaced because it is a non-empty directory
    • 

  • UnsupportedOperationException: If the way of copying described by an option is not supported
    • 

  • SecurityException: If the write access to the target file is denied by the security manager
    • 



Implementation:


Example


Java























import java.io.IOException;


import java.nio.file.Files;


import java.nio.file.Path;


import java.nio.file.Paths;


import java.nio.file.StandardCopyOption;


 




public class GFG {


 


    


    public static void main(String[] args)


    {


        


        Path pathIn = (Path)Paths.get("/usr", "local",


                                      "bin", "fileIn.txt");


        


        Path pathOut = (Path)Paths.get(


            "/usr", "local", "bin", "fileOut.txt");


 


        System.out.println("Path of target file: "


                           + pathIn.toString());


 


        System.out.println("Path of source file: "


                           + pathOut.toString());


 


        


        try {


 


            


            System.out.println(


                "Number of bytes copied: "


                + Files.copy(


                    pathOut, pathIn,


                    StandardCopyOption.REPLACE_EXISTING));


        }


 


        


        catch (IOException e) {


 


            


            e.printStackTrace();


        }


    }


}












 Output:


Path of target file: /usr/local/bin/fileIn.txt
Path of source file: /usr/local/bin/fileOut.txt
Number of bytes copied: 13 










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