Java Reference
In-Depth Information
If you want to read an entire line of text at a time instead of reading a file character by
character, you can use the
BufferedReader
class in conjunction with a
FileReader
.
The
BufferedReader
class reads a character input stream and buffers it for better effi-
ciency. You must have an existing
Reader
object of some kind to create a buffered ver-
sion. The following constructors can be used to create a
BufferedReader
:
BufferedReader(
Reader
)
—Creates a buffered character stream associated with
the specified
Reader
object, such as
FileReader
n
BufferedReader(
Reader
,
int
)
—Creates a buffered character stream associated
with the specified
Reader
and with a buffer of
int
size
n
A buffered character stream can be read using the
read()
and
read(
char[]
,
int
,
int
)
methods described for
FileReader
. You can read a line of text using the
readLine()
method.
The
readLine()
method returns a
String
object containing the next line of text on the
stream, not including the character or characters that represent the end of a line. If the
end of the stream is reached, the value of the string returned will be equal to
null
.
An end-of-line is indicated by any of the following:
A newline character (
'\n'
)
n
A carriage return character (
'\r'
)
n
A carriage return followed by a newline (“\n\r”)
n
The project contained in Listing 15.7 is a Java application that reads its own source file
through a buffered character stream.
LISTING 15.7
The Full Text of
SourceReader.java
1: import java.io.*;
2:
3: public class SourceReader {
4: public static void main(String[] arguments) {
5: try {
6: FileReader file = new
7: FileReader(“SourceReader.java”);
8: BufferedReader buff = new
9: BufferedReader(file);
10: boolean eof = false;
11: while (!eof) {
12: String line = buff.readLine();
13: if (line == null)
