Java CharBuffer compact()用法及代码示例

java.nio.CharBuffer类的compact()方法用于压缩给定的缓冲区。

缓冲区当前位置与其极限之间的值将复制到缓冲区的开头。然后将缓冲区的位置设置为n + 1，并将其限制设置为其容量。缓冲区的位置设置为复制的浮点数。

用法:

public abstract CharBuffer compact()

返回值：此方法返回具有与此缓冲区相同内容的新CharBuffer。

异常：如果此缓冲区是只读的，则此方法引发ReadOnlyBufferException。

以下示例程序旨在说明compact()方法：

示例1:

// Java program to demonstrate 
// compact() method 
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the CharBuffer 
        int capacity = 10; 
  
        // Creating the CharBuffer 
  
        // creating object of Intbuffer 
        // and allocating size capacity 
        CharBuffer ic = CharBuffer.allocate(capacity); 
  
        // putting the value in Intbuffer 
        ic.put('a'); 
        ic.put('b'); 
        ic.put('c'); 
  
        // print the CharBuffer 
        System.out.println("Original CharBuffer: "
                           + Arrays.toString(ic.array())); 
  
        System.out.println("Position: " + ic.position()); 
  
        System.out.println("limit: " + ic.limit()); 
  
        // Creating a compacted CharBuffer of same CharBuffer 
        // using compact() method 
        CharBuffer CharBuffer = ic.compact(); 
  
        // print the CharBuffer 
        System.out.println("\nCompacted CharBuffer: "
                           + Arrays.toString(CharBuffer.array())); 
  
        System.out.println("Position: " + CharBuffer.position()); 
  
        System.out.println("limit: " + CharBuffer.limit()); 
  
        // putting the value in compacted Intbuffer 
        CharBuffer.put('g'); 
  
        // print the CharBuffer 
        System.out.println("\nUpdated Compacted CharBuffer: "
                           + Arrays.toString(CharBuffer.array())); 
        System.out.println("Position: " + CharBuffer.position()); 
        System.out.println("limit: " + CharBuffer.limit()); 
    } 
}

输出：

Original CharBuffer: [a, b, c, , , , , , , ]
Position: 3
limit: 10

Compacted CharBuffer: [, , , , , , , , , ]
Position: 7
limit: 10

Updated Compacted CharBuffer: [, , , , , , , g, , ]
Position: 8
limit: 10

示例2:

// Java program to demonstrate 
// compact() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the CharBuffer 
        int capacity = 10; 
  
        // Creating the CharBuffer 
        try { 
  
            // creating object of CharBuffer 
            // and allocating size capacity 
            CharBuffer cb = CharBuffer.allocate(capacity); 
  
            // putting the value in CharBuffer 
            cb.put('a'); 
            cb.put('b'); 
            cb.put('b'); 
            cb.rewind(); 
  
            // Creating a read-only copy of CharBuffer 
            // using asReadOnlyBuffer() method 
            CharBuffer cb1 = cb.asReadOnlyBuffer(); 
  
            // print the ReadOnlyBuffer 
            System.out.print("ReadOnlyBuffer CharBuffer: "); 
            while (cb1.hasRemaining()) 
                System.out.print(cb1.get() + ", "); 
            System.out.println(""); 
  
            // print the Position of CharBuffer cb 
            System.out.println("\nPosition: " + cb.position()); 
  
            // print the Limit of CharBuffer cb 
            System.out.println("\nlimit: " + cb.limit()); 
  
            // Creating a compacted CharBuffer of same ReadOnlyBuffer 
            // using compact() method 
            System.out.println("\nTrying to compact the ReadOnlyBuffer cb1"); 
            CharBuffer CharBuffer = cb1.compact(); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("Exception throws " + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("Exception throws " + e); 
        } 
    } 
}

输出：

ReadOnlyBuffer CharBuffer: a, b, b, , , , , , , , 

Position: 0

limit: 10

Trying to compact the ReadOnlyBuffer cb1
Exception throws java.nio.ReadOnlyBufferException

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注：本文由纯净天空筛选整理自gopaldave大神的英文原创作品 CharBuffer compact() method in Java。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。