Input/Output - Beginning Java 8 Language Features - page 318

public static void consumeData(PipedInputStream pis) {
try {
int num = -1;
while ((num = pis.read()) != -1) {
System.out.println("Reading: " + num);
}
pis.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
}
Writing: 1
Reading: 1
...
Writing: 50
Reading: 50
Reading and Writing Primitive Data Types
An object of the DataInputStream class is used to read Java primitive data type values in a machine-independent way
from an input stream. An object of the DataOutputStream class is used to write Java primitive data type values in a
machine-independent way to an output stream.
The DataInputStream class contains readXxx() methods to read a value of data type Xxx , where Xxx is a Java
primitive data type such as int , char , etc. For example, to read an int value, it contains a readInt() method; to read a
char value, it has a readChar() method, etc. It also supports reading strings using the readUTF() method.
The DataOutputStream class contains a writeXxx(Xxx value) method corresponding to each the readXxx()
method of the DataInputStream class, where Xxx is a Java primitive data type. It supports writing a string to an output
stream using the writeUTF(String text) method. Note that these classes are concrete decorators, which provide
you a convenient way to read and write Java primitive data type values and strings using input and output streams,
respectively. You must have an underlying concrete component linked to a data source or a data sink to use these
classes. For example, to write Java primitive data type values to a file named primitives.dat , you construct an object
of DataOutputStream as follows:
DataOutputStream dos = new DataOutputStream(new FileOutputStream("primitives.dat"));
Listing 7-21 writes an int value, a double value, a boolean value, and a string to a file named primitives.dat .
The file path in the output may be different when you run this program. Listing 7-22 reads those values back. Note that
you must read the values using DataInputStream in the same order they were written using DataOutputStream . You
need to run the WritingPrimitives class before you run the ReadingPrimitives class.