In Java, there are many ways to create and write to a file.
Files.newBufferedWriter(Java 8)Files.write(Java 7)PrintWriterFile.createNewFile
Note
I prefer the Java 7 nio Files.write to create and write to a file, because it has much cleaner code and auto close the opened resources.
Files.write(
Paths.get(fileName),
data.getBytes(StandardCharsets.UTF_8));
1. Java 8 Files.newBufferedWriter
1.1 This example shows how to use the new Java 8 Files.newBufferedWriter to create and write to a file.
package com.mkyong.io.file;
import java.io.BufferedWriter;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
public class CreateFileJava8 {
public static void main(String[] args) {
String fileName = "/home/mkyong/newFile.txt";
Path path = Paths.get(fileName);
// default, create, truncate and write to it.
try (BufferedWriter writer =
Files.newBufferedWriter(path, StandardCharsets.UTF_8)) {
writer.write("Hello World !!");
} catch (IOException e) {
e.printStackTrace();
}
/* Append mode.
try (BufferedWriter writer =
Files.newBufferedWriter(path,
StandardCharsets.UTF_8,
StandardOpenOption.APPEND)){
writer.write("Hello World !!");
} catch (IOException e) {
e.printStackTrace();
}*/
}
}
2. Java 7 Files.write
2.1 This example shows how to use the Java 7 nio Files.write to create and write to a file.
By default, it opens a file for writing; create the file if it doesn’t exist; truncate the current content if the file exists.
package com.mkyong.io.file;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
public class CreateFileNio {
public static void main(String[] args) {
String fileName = "/home/mkyong/newFile.txt";
String content = "hello world!";
try {
// Java 1.7
// default, create and write to it.
Files.write(
Paths.get(fileName),
content.getBytes(StandardCharsets.UTF_8));
// Append content
/*Files.write(
Paths.get(fileName),
content.getBytes(StandardCharsets.UTF_8),
StandardOpenOption.APPEND);*/
} catch (IOException e) {
e.printStackTrace();
}
}
}
2.2 Review the Files.write. source code; it uses the try-with-resources to auto-close the opened resources.
package java.nio.file;
public final class Files {
public static Path write(Path path, byte[] bytes, OpenOption... options)
throws IOException
{
// ensure bytes is not null before opening file
Objects.requireNonNull(bytes);
try (OutputStream out = Files.newOutputStream(path, options)) {
int len = bytes.length;
int rem = len;
while (rem > 0) {
int n = Math.min(rem, BUFFER_SIZE);
out.write(bytes, (len-rem), n);
rem -= n;
}
}
return path;
}
//...
}
3. PrintWriter
3.1 This example shows how to use PrintWriter to create and write to a file.
package com.mkyong.io.file;
import java.io.IOException;
import java.io.PrintWriter;
import java.nio.charset.StandardCharsets;
public class CreateFile {
public static void main(String[] args) {
String fileName = "/home/mkyong/newFile.txt";
// Java 10, new constructor, support Charsets
try (PrintWriter writer = new PrintWriter(fileName, StandardCharsets.UTF_8)) {
writer.println("first line!");
writer.println("second line!");
} catch (IOException e) {
e.printStackTrace();
}
// Java 1.5
/*try (PrintWriter writer = new PrintWriter(fileName, "UTF-8")) {
writer.println("first line!");
writer.println("second line!");
} catch (IOException e) {
e.printStackTrace();
}*/
}
}
4. File.createNewFile()
4.1 This example shows how to use the File.createNewFile() to create an empty file, and the FileWriter to write data to the file.
package com.mkyong.io.file;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
public class CreateFile2 {
public static void main(String[] args) {
String fileName = "/home/mkyong/newFile.txt";
try {
File file = new File(fileName);
// true if file does no exist and was created successfully.
// false if file is already exists
if (file.createNewFile()) {
System.out.println("File is created!");
} else {
System.out.println("File already exists.");
}
// Write to file
try (FileWriter writer = new FileWriter(file)) {
writer.write("Hello World!");
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
Download Source Code
$ git clone https://github.com/mkyong/core-java
$ cd java-io
It doesn’t work. new File(String) throws a NullPointerException which is not being caught in this example.
Only throws NullPointerException if the passed argument is null.
nice article
how to create file within project folder like webContent?
thank yu
it helped in my exam
I copied your codes on eclipse but file doesn’t create
Can you help me!!!!
If you get the message that says “A required privelage does not exist”, change the file path from C:\newfile.txt to some place else. That may solve the problem.
Can you tell me that if the user creates a file than again he want to create a new file again . by entering his own file url e.g newfile.txt …. please sir help me?
It is not possible as the file already exists. You can create a new file in a separate folder by changing the path.
Thanks it cleared most of my doubts, but can u tell me what is the purpose of this “file.createNewFile”.
If doesnt exist it creates new file
hiiiiiiiiiii
Thanks, it helped to overcome/solve problem FileNotFoundException in IntelliJ IDEA
Very simple example for Java beginners.
i get an error saying access denied
Must Read
Good Tutorial
Hello mates, its fantastic article on the topic of cultureand
entirely defined, keep it up all the time.
showing command like do without try and catch
“enter the file name to be created” i want write the prg for this? if anyone know pls help
your doing very well for creating good JAVA Programmers by learning from ur Website sir,,,,,,,,
i likes ur website a lot and as well as u….
From Racha Suman, India
The tutorials would be good with documentation/comments there is really no beginner who can grasp this stuff all at once.
I want to know is this a static page or dynamically generated