FileWriter

FileWriter is a class in the Java standard library that provides a character stream for writing to files. It is part of the java.io package and is designed to simplify writing text data to a file by handling the underlying byte stream conversion automatically. FileWriter is generally used when writing character data, such as text, rather than binary data.

FileWriter is typically constructed with a file name or a File object, and may optionally enable append mode. Example constructors include new FileWriter(String fileName), new FileWriter(File file), and new FileWriter(String fileName, boolean append). Many of these constructors throw IOException if the file cannot be created or opened.

When you write through a FileWriter, the data is converted from characters to bytes using the platform’s default charset, unless an alternative approach is used. For explicit character encoding, developers often wrap a FileOutputStream in an OutputStreamWriter with a specified Charset, or use higher-level APIs such as Files.newBufferedWriter(Path, Charset).

FileWriter inherits from Writer and supports typical writer operations such as write(char[]), write(String), flush, and close. For improved performance on larger writes, it is common to wrap a FileWriter with a BufferedWriter, which minimizes the number of I/O operations.

Limitations include the reliance on the platform default encoding and that FileWriter is intended for text data. For binary data, other streams such as FileOutputStream are more appropriate.