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

java.nio.ByteBuffer类的asCharBuffer()方法用于创建此字节缓冲区作为char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,其容量和限制将是此缓冲区中剩余的字节数除以2,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 CharBuffer asCharBuffer()

返回值:此方法返回一个新的char缓冲区。

下面是说明asCharBuffer()方法的示例:

示例1:

// Java program to demonstrate 
// asCharBuffer() 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 view as char buffer 
            // and putting a string value 
            bb.asCharBuffer().put("TajMahal"); 
  
            // Declaring char variable c 
            char c; 
  
            // print the ByteBuffer 
            System.out.print("Char buffer : "); 
            while ((c = bb.getChar()) != 0) 
                System.out.print(c + " "); 
            System.out.println(); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}
输出:
Char buffer : T a j M a h a l

示例2:

// Java program to demonstrate 
// asCharBuffer() method 
// for Read only 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 
            // char buffer 
            CharBuffer cb = bb.asCharBuffer(); 
  
            // putting the value in charbuffer 
            cb.put("Tajmahal"); 
            cb.rewind(); 
  
            // Declaring variable c 
            char c; 
  
            // print the ByteBuffer 
            System.out.print("Char buffer : "); 
            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 char buffer 
            CharBuffer cb1 = bb1.asCharBuffer(); 
  
            // putting the value in charbuffer 
            System.out.println("\n\nTrying to put the string"
                               + " into read only charbuffer"); 
            cb1.put("Tajmahal"); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}
输出:
Char buffer : T a j m a h a l 

Trying to put the string into read only charbuffer
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 asCharBuffer() 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。