API Contents - SCJP Sun Certified Programmer for Java Platform SE6 - page 291

3. Line 8 instantiates a FileInputStream for src and line 9 instantiates a FileOutput-
Stream for dest .
4. The while loop on line 12 reads one byte at time from the source file. If the read
method returns -1 , the end of the file has been reached and the while loop terminates.
Otherwise, the byte is written to the destination file.
5. Be sure to close all streams, as done on lines 16 and 17.
Notice that the source fi le I chose to copy was a bytecode fi le, which is not just character
data. (The Reader and Writer classes would not have worked for this application because
the data is raw bytes.) An exact copy of States.class is created in a new fi le named
copyofStates.class .
The next section discusses two useful high-level streams, DataInputStream and
DataOutputStream , which fi lter byte streams into primitive types and strings.
The DataInputStream and DataOutputStream Classes
The CopyFile program from the previous section used only low-level streams, but most
input and output use the high-level streams as well. For example, the DataInputStream and
DataOutputStream classes are high-level streams that contain methods for reading and writ-
ing the eight Java primitive types as well as String objects. The following ContactManager
program demonstrates the DataInputStream and DataOutputStream classes. The program
uses the following Contact class, a basic representation of a person's contact information:
1. package com.sybex.io;
2.
3. public class Contact {
4. public String name;
5. public int age;
6. public long cellPhone;
7.
8. public Contact(String name, int age, long cellPhone) {
9. this.name = name;
10. this.age = age;
11. this.cellPhone = cellPhone;
12. }
13.
14. public String toString() {
15. return name + “ “ + age + ” “ + cellPhone + ”\n”;
16. }
17. }