Overwrite file java bufferedwriter

Find centralized, trusted content and collaborate around the technologies you use most. Connect and share knowledge within a single location that is structured and easy to search. Make sure that when you create an instance of a FileWriter , that you are appending to the end of it. This can be done by using this specific FileWriter constructor which takes an additional boolean as a second parameter.

This boolean tells the FileWriter to append to the end of the file, rather than overwriting the file. By default FileWriter will overwrite the file. What you might want to do is define the reader in the following manner: new FileWriter "encoded. Hope this helps! I'm not sure what this code is supposed to do. It throws an error if your input string is more than one character long, because you close your FileWriter inside the loop, then try to write to it again. I'm interpreting your question the following way: you're wondering why only the most recent output is in the file.

In that case, it's because you didn't create your FileWriter in append mode. Look at the different constructors available for FileWriter, and use the one that allows you to append to the file. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Since: JDK1. Path, java. Charset, java. Field Summary Fields inherited from class java. Writer lock Constructor Summary Constructors Constructor and Description BufferedWriter Writer out Creates a buffered character-output stream that uses a default-sized output buffer.

BufferedWriter Writer out, int sz Creates a new buffered character-output stream that uses an output buffer of the given size. Methods inherited from class java. Writer append , append , append , write , write Methods inherited from class java.

Object clone , equals , finalize , getClass , hashCode , notify , notifyAll , toString , wait , wait , wait Constructor Detail BufferedWriter public BufferedWriter Writer out Creates a buffered character-output stream that uses a default-sized output buffer. Parameters: out - A Writer BufferedWriter public BufferedWriter Writer out, int sz Creates a new buffered character-output stream that uses an output buffer of the given size.

Ordinarily this method stores characters from the given array into this stream's buffer, flushing the buffer to the underlying stream as needed. If the requested length is at least as large as the buffer, however, then this method will flush the buffer and write the characters directly to the underlying stream.

Thus redundant BufferedWriter s will not copy data unnecessarily. When you create a Java FileWriter you can decide if you want to overwrite any existing file with the same name, or if you want to append to any existing file. You decide that by choosing what FileWriter constructor you use. The FileWriter constructor taking just one parameter, the file name, will overwrite any existing file:.

FileWriter has a constructor that takes 2 parameters too: The file name and a boolean. The boolean indicates whether to append or overwrite an existing file. Here are two Java FileWriter examples showing that:. The FileWriter assumes that you want to encode the bytes to the file using the default character encoding for the computer your application is running on. This may not always be what you want, and you cannot change it! If you want to specify a different character encoding scheme, don't use a FileWriter.

The OutputStreamWriter lets you specify the character encoding scheme to use when writing bytes to the underlying file. The Java FileWriter write int method writes the lower 16 bit of the int to the destination the FileWriter is connected to, as a single character.

Here is an example of writing a single character to a Java FileWriter :. The Java FileWriter also has a write char[] method which can write an array of characters to the destination the FileWriter is connected to.

The write char[] method returns the number of characters actually written to the FileWriter. Here is an example of writing an array of chars to a Java FileWriter :. It is faster to write an array of characters to a Java FileWriter than writing one character at a time. The speedup can be quite significant - up to 10 x higher or more.