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Java - ByteBuffer asLongBuffer()用法及代码示例

java.nio.ByteBuffer类的asLongBuffer()方法用于创建作为长缓冲区的此字节缓冲区的视图。

新缓冲区的内容将从该缓冲区的当前位置开始。对该缓冲区内容的更改将在新缓冲区中可见,反之亦然;这两个缓冲区的位置,限制和标记值将是独立的。

新缓冲区的位置将为零,其容量和限制将是该缓冲区中剩余的字节数除以8,并且其标记将不确定。当且仅当该缓冲区是直接缓冲区时,新缓冲区才是直接缓冲区;当且仅当该缓冲区是只读缓冲区时,新缓冲区才是只读缓冲区。


用法:

public abstract LongBuffer asLongBuffer()

返回值:此方法返回一个新的长缓冲区。

下面是说明asLongBuffer()方法的示例:

范例1:

// Java program to demonstrate 
// asLongBuffer() 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); 
  
            // changeing  bytebuffer into 
            // LongBuffer 
            LongBuffer lb = bb.asLongBuffer(); 
  
            // putting the value in LongBuffer 
            lb.put(1000000); 
            lb.put(2000000); 
            lb.put(3000000); 
            lb.put(3000000); 
            lb.rewind(); 
  
            // Declaring variable c 
            long c; 
  
            // print the ByteBuffer 
            System.out.print("LongBuffer : "); 
            while ((c = lb.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:
LongBuffer : 1000000  2000000  3000000  3000000

范例2:

// Java program to demonstrate 
// asLongBuffer() 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); 
  
            // changeing  bytebuffer into 
            // LongBuffer 
            LongBuffer lb = bb.asLongBuffer(); 
  
            // putting the value in LongBuffer 
            lb.put(1000000); 
            lb.put(2000000); 
            lb.put(3000000); 
            lb.rewind(); 
  
            // Declaring variable c 
            long c; 
  
            // print the ByteBuffer 
            System.out.print("LongBuffer : "); 
            while ((c = lb.get()) != 0) 
                System.out.print(c + "  "); 
  
            // Creating a read-only copy of ByteBuffer 
            // using asReadOnlyBuffer() method 
            ByteBuffer bb1 = bb.asReadOnlyBuffer(); 
  
            // changeing read-only bytebuffer into 
            // read-only LongBuffer 
            LongBuffer lb1 = bb1.asLongBuffer(); 
  
            // putting the value in read-only LongBuffer 
            System.out.println("\n\nTrying to put the value "
                               + "in read only LongBuffer"); 
            lb1.put(10); 
            lb1.put(20); 
            lb1.put(30); 
            lb1.rewind(); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}
输出:
LongBuffer : 1000000  2000000  3000000  

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


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注:本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 ByteBuffer asLongBuffer() method in Java with Examples。非经特殊声明,原始代码版权归原作者所有,本译文的传播和使用请遵循“署名-相同方式共享 4.0 国际 (CC BY-SA 4.0)”协议。