Java DataOutputStream size（）方法及示例

DataOutputStream类的size()方法 (DataOutputStream Class size() method)

size() method is available in java.io package.
size()方法在java.io包中可用。
size() method is used to return the size of this stream or in other words, we can say it returns the value of the variable counter that contains written bytes.
size()方法用于返回此流的大小，换句话说，可以说它返回包含已写入字节的变量计数器的值。
size() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
size()方法是一种非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。
size() method does not throw an exception at the time of returning size.
返回size时， size()方法不会引发异常。

Syntax:

句法：

    public final int size();

Parameter(s):

参数：

It does not accept any parameter.
它不接受任何参数。

Return value:

返回值：

The return type of the method is int, it returns the last value of the variable counter.

方法的返回类型为int ，它返回变量计数器的最后一个值。

Example:

例：

// Java program to demonstrate the example 
// of int size() method of DataOutputStream
import java.io.*;
public class SizeOfDOS {
public static void main(String[] args) throws IOException {
InputStream is_stm = null;
DataInputStream dis_stm = null;
FileOutputStream fos_stm = null;
DataOutputStream dos_stm = null;
byte[] b_arr = {
12,
20,
45,
98,
75,
69,
30,
58,
47,
61,
83,
55
};
try {
// Instantiate FileInputStream, 
// DataInputStream, FileOutputStream
// and DataOutputStream 
fos_stm = new FileOutputStream("C:\\Users\\Preeti Jain\\Desktop\\programs\\includehelp.txt");
dos_stm = new DataOutputStream(fos_stm);
is_stm = new FileInputStream("C:\\Users\\Preeti Jain\\Desktop\\programs\\includehelp.txt");
dis_stm = new DataInputStream(is_stm);
// Loop to write each byte till end
for (byte val: b_arr) {
// By using write() method isto
// write a byte value to the
// DataOutputStream dos_stm
dos_stm.write(val);
}
// Loop To Read Available Data till end
while (dis_stm.available() > 0) {
// By using read() method isto read 
// byte from dis_stm
int in = dis_stm.read();
System.out.println("dis_stm.read(): " + in );
}
System.out.println();
// By using size() method isto return
// size of this stream
int size = dos_stm.size();
System.out.println("dos_stm.size(): " + size);
} catch (Exception ex) {
System.out.println(ex.toString());
} finally {
// To free system resources linked
// with these streams
if (is_stm != null)
is_stm.close();
if (dis_stm != null)
dis_stm.close();
if (dos_stm != null)
dos_stm.close();
if (fos_stm != null)
fos_stm.close();
}
}
}

Output

输出量

dis_stm.read(): 12
dis_stm.read(): 20
dis_stm.read(): 45
dis_stm.read(): 98
dis_stm.read(): 75
dis_stm.read(): 69
dis_stm.read(): 30
dis_stm.read(): 58
dis_stm.read(): 47
dis_stm.read(): 61
dis_stm.read(): 83
dis_stm.read(): 55dos_stm.size(): 12