Java ByteBuffer asShortBuffer()方法及示例

java.nio.ByteBuffer 类的 asShortBuffer() 方法用于将此字节缓冲区创建为一个短缓冲区的视图。

新缓冲区的内容将从此缓冲区的当前位置开始。这个缓冲区内容的变化将在新缓冲区中可见，反之亦然；两个缓冲区的位置、极限和标记值将是独立的。

新缓冲区的位置将是0，它的容量和极限将是这个缓冲区中剩余的字节数除以2，它的标记将是未定义的。当且仅当这个缓冲区是直接的，新的缓冲区将是直接的，当且仅当这个缓冲区是只读的，它将是只读的。

语法：

public abstract ShortBuffer asShortBuffer()

返回值： 该方法返回一个新的短缓冲区。

以下是说明asShortBuffer()方法的例子：

例子1：

// Java program to demonstrate
// asShortBuffer() method
// for ByteBuffer
 
import java.nio.*;
import java.util.*;
 
public class GFG {
 
    public static void main(String[] args)
    {
 
        // Declaring the capacity  of the ByteBuffer
        int capacity = 50;
 
        // Creating the ByteBuffer
        try {
 
            // creating object of  ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);
 
            // changing  bytebuffer into
            // ShortBuffer
            ShortBuffer cb = bb.asShortBuffer();
 
            // putting the value in ShortBuffer
            cb.put((short)20);
            cb.put((short)30);
            cb.put((short)40);
            cb.put((short)50);
            cb.rewind();
 
            // Declaring variable c
            short c;
 
            // print the ByteBuffer
            System.out.print("ShortBuffer : ");
            while ((c = cb.get()) != 0)
                System.out.print(c + "  ");
        }
 
        catch (IllegalArgumentException e) {
 
            System.out.println("Exception thrown : " + e);
        }
 
        catch (ReadOnlyBufferException e) {
 
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出

ShortBuffer : 20  30  40  50

实例2：

// Java program to demonstrate
// asShortBuffer() method
// for ByteBuffer
 
import java.nio.*;
import java.util.*;
 
public class GFG {
 
    public static void main(String[] args)
    {
 
        // Declaring the capacity  of the ByteBuffer
        int capacity = 50;
 
        // Creating the ByteBuffer
        try {
 
            // creating object of  ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);
 
            // changing  bytebuffer into
            // ShortBuffer
            IntBuffer cb = bb.asIntBuffer();
 
            // putting the int to short typecast value in ShortBuffer
            cb.put((short)10);
            cb.put((short)20);
            cb.put((short)30);
            cb.rewind();
 
            // Declaring variable c
            int c;
 
            // print the ByteBuffer
            System.out.print("ShortBuffer : ");
            while ((c = cb.get()) != 0)
                System.out.print(c + "  ");
 
            // Creating a read-only copy of ByteBuffer
            // using asReadOnlyBuffer() method
            ByteBuffer bb1 = bb.asReadOnlyBuffer();
 
            // changing read-only bytebuffer into
            // read-only ShortBuffer
            ShortBuffer cb1 = bb1.asShortBuffer();
 
            // putting the int to short typecast value in read-only ShortBuffer
            System.out.println("\n\nTrying to put the value "
                               + "in read only ShortBuffer");
            cb1.put((short)10);
            cb1.put((short)20);
            cb1.put((short)30);
            cb1.rewind();
        }
 
        catch (IllegalArgumentException e) {
 
            System.out.println("Exception thrown : " + e);
        }
 
        catch (ReadOnlyBufferException e) {
 
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出

ShortBuffer : 10  20  30  

Trying to put the value in read only ShortBuffer
Exception thrown : java.nio.ReadOnlyBufferException