Java ByteBuffer asDoubleBuffer()用法及代码示例

java.nio.ByteBuffer类的asDoubleBuffer()方法用于创建此字节缓冲区作为双缓冲区的视图。

新缓冲区的内容将从该缓冲区的当前位置开始。对该缓冲区内容所做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 DoubleBuffer asDoubleBuffer()

返回值：此方法返回一个新的双缓冲区。

下面是说明asDoubleBuffer()方法的示例：

范例1：

// Java program to demonstrate 
// asDoubleBuffer() 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 
            // DoubleBuffer 
            DoubleBuffer cb = bb.asDoubleBuffer(); 
  
            // putting the value in DoubleBuffer 
            cb.put(5001.99); 
            cb.put(5002.99); 
            cb.put(5003.99); 
            cb.rewind(); 
  
            // Declaring variable c 
            double c; 
  
            // print the ByteBuffer 
            System.out.print("DoubleBuffer : "); 
            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：

DoubleBuffer : 5001.99 5002.99 5003.99

范例2：

// Java program to demonstrate 
// asDoubleBuffer() 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 
            // DoubleBuffer 
            DoubleBuffer cb = bb.asDoubleBuffer(); 
  
            // putting the value in DoubleBuffer 
            cb.put(5001.99); 
            cb.put(5002.99); 
            cb.put(5003.99); 
            cb.rewind(); 
  
            // Declaring variable c 
            double c; 
  
            // print the ByteBuffer 
            System.out.print("DoubleBuffer : "); 
            while ((c = cb.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 DoubleBuffer 
            DoubleBuffer cb1 = bb1.asDoubleBuffer(); 
  
            // putting the value in read-only double buffer 
            System.out.println("\n\nTrying to put the value "
                               + "in read only double buffer"); 
            cb1.put(5001.99); 
            cb1.put(5002.99); 
            cb1.put(5003.99); 
            cb1.rewind(); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

DoubleBuffer : 5001.99 5002.99 5003.99 

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

相关用法

注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 ByteBuffer asDoubleBuffer() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。