Java Cookbook

Opening a File by Name

Problem

The Java documentation doesn’t have methods for opening files. How do I connect a filename on disk with a Reader, Writer, or Stream?

Solution

Construct a FileReader , a FileWriter, a FileInputStream, or a FileOutputStream.

Discussion

The action of constructing a FileReader, FileWriter, FileInputStream, or FileOutputStream corresponds to the “open” operation in most I/O packages. There is no explicit open operation, perhaps as a kind of rhetorical flourish of the Java API’s object-oriented design. So to read a text file, you’d create, in order, a FileReader and a BufferedReader. To write a file a byte at a time, you’d create a FileOutputStream, and probably a BufferedOutputStream for efficiency:

// OpenFileByName.java
BufferedReader is = new BufferedReader(new FileReader("myFile.txt"));
BufferedOutputStream bytesOut = new BufferedOutputStream(
    new FileOutputStream("bytes.dat"));
...
bytesOut.close(  );

Remember that you will need to handle IOException around these calls.