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9. while(currentState != null) {
10. System.out.println(“State: “ + currentState);
11. currentState = in.readLine();
12. }
13. }catch(IOException e) {
14. e.printStackTrace();
15. }
16. }
17. }
Here is what the
States
program does:
1.
A new
FileReader
is instantiated on line 6. If the file
states.txt
is not found or can-
not be read from, a
FileNotFoundException
is thrown.
2.
A
BufferedReader
is chained to the
FileReader
to buffer the data.
3.
Line 8 reads in the first line of text from the file.
4.
On line 9, if the previous line of text read from the file is not
null
, we print it to the
console and read in the next line of the file on line 11.
5.
The
while
loop continues line by line until the end of the file is reached, at which point
the
readLine
method returns
null
.
The output of the
States
program is
State: New York
State: Alabama
State: South Dakota
State: Nevada
Figure 4.7 shows the
BufferedReader
chained to the
FileReader
. A
BufferedReader
cannot exist on its own. It is a high-level stream so it must be attached to an existing
stream.
FIGURE 4.7
A
BufferedReader
is chained to a
FileReader
.
BufferedReader
“New York”
FileReader
1011010
“states.txt”
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