Java CharBuffer flip()用法及代码示例

java.nio.CharBuffer类的flip()方法用于翻转此缓冲区。将限制设置为当前位置，然后将该位置设置为零。如果定义了标记，则将其丢弃。在序列完成channel-read或放置操作之后，调用此方法为序列进行准备的channel-write或相对get操作。

例如：

buf.put(magic); // Prepend header
in.read(buf); // Read data into rest of buffer
buf.flip(); // Flip buffer
out.write(buf); // Write header + data to channel

当将数据从一个地方传输到另一个地方时，通常将此方法与compact()方法结合使用。

用法:

public final CharBuffer flip()

返回值：此方法返回此缓冲区。

下面是说明flip()方法的示例：

范例1：

// Java program to demonstrate 
// flip() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Declare and initialize the char array 
        char[] cb = { 'a', 'b', 'c' }; 
  
        // wrap the char array into CharBuffer 
        // using wrap() method 
        CharBuffer charBuffe 
            r 
            = CharBuffer.wrap(cb); 
  
        // set position at index 1 
        charBuffer.position(1); 
  
        // print the char buffer 
        System.out.println("CharBuffer before flip:"
                           + Arrays.toString( 
                                 charBuffer.array()) 
                           + "\nPosition:"
                           + charBuffer.position() 
                           + "\nLimit:"
                           + charBuffer.limit()); 
  
        // Flip the charBuffer 
        // using flip() method 
        charBuffer.flip(); 
  
        // print the byte buffer 
        System.out.println("\nCharBuffer after flip:"
                           + Arrays.toString( 
                                 charBuffer.array()) 
                           + "\nPosition:"
                           + charBuffer.position() 
                           + "\nLimit:"
                           + charBuffer.limit()); 
    } 
}

输出：

CharBuffer before flip:[a, b, c]
Position:1
Limit:3

CharBuffer after flip:[a, b, c]
Position:0
Limit:1

范例2：

// Java program to demonstrate 
// flip() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
        // defining and allocating CharBuffer 
        // using allocate() method 
        CharBuffer charBuffer 
            = CharBuffer.allocate(4); 
  
        // append char value in charBuffer 
        // using append() method 
        charBuffer.append('a'); 
        charBuffer.append('b'); 
  
        // print the char buffer 
        System.out.println("CharBuffer before flip:"
                           + Arrays.toString( 
                                 charBuffer.array()) 
                           + "\nPosition:"
                           + charBuffer.position() 
                           + "\nLimit:"
                           + charBuffer.limit()); 
  
        // Flip the charBuffer 
        // using flip() method 
        charBuffer.flip(); 
  
        // print the char buffer 
        System.out.println("CharBuffer before flip:"
                           + Arrays.toString( 
                                 charBuffer.array()) 
                           + "\nPosition:"
                           + charBuffer.position() 
                           + "\nLimit:"
                           + charBuffer.limit()); 
    } 
}

输出：

CharBuffer before flip:[a, b, c,  ]
Position:3
Limit:4
CharBuffer before flip:[a, b, c,  ]
Position:0
Limit:3

参考： https://docs.oracle.com/javase/9/docs/api/java/nio/CharBuffer.html#flip-

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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 CharBuffer flip() methods 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。