Java LongBuffer rewind()用法及代码示例

java.nio.LongBuffer类的rewind()方法用于倒带此缓冲区。通过倒带此Buffer，可以执行以下操作：

当前位置设置为零
如果有标记，则将其丢弃，但标记值不变。

用法:

public LongBuffer rewind()

参数：此方法不接受任何参数。

返回值：倒带后，此方法返回此缓冲区。

下面是说明rewind()方法的示例：

范例1：

// Java program to demonstrate 
// rewind() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
        // defining and allocating LongBuffer 
        // using allocate() method 
        LongBuffer longBuffer = LongBuffer.allocate(4); 
  
        // put long value in longBuffer 
        // using put() method 
        longBuffer.put(10); 
        longBuffer.put(20); 
  
        // print the long buffer 
        System.out.println( 
            "Buffer before operation: "
            + Arrays.toString( 
                  longBuffer.array()) 
            + "\nPosition: "
            + longBuffer.position() 
            + "\nLimit: "
            + longBuffer.limit()); 
  
        // rewind the Buffer 
        // using rewind() method 
        longBuffer.rewind(); 
  
        // print the longbuffer 
        System.out.println( 
            "\nBuffer after operation: "
            + Arrays.toString( 
                  longBuffer.array()) 
            + "\nPosition: "
            + longBuffer.position() 
            + "\nLimit: "
            + longBuffer.limit()); 
    } 
}

输出：

Buffer before operation: [10, 20, 0, 0]
Position: 2
Limit: 4

Buffer after operation: [10, 20, 0, 0]
Position: 0
Limit: 4

范例2：

// Java program to demonstrate 
// rewind() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
        // defining and allocating LongBuffer 
        // using allocate() method 
        LongBuffer longBuffer 
            = LongBuffer.allocate(5); 
  
        // put long value in longBuffer 
        // using put() method 
        longBuffer.put(10); 
        longBuffer.put(20); 
        longBuffer.put(30); 
  
        // mark will be going to 
        // discarded by rewind() 
        longBuffer.mark(); 
  
        // print the buffer 
        System.out.println( 
            "Buffer before operation: "
            + Arrays.toString( 
                  longBuffer.array()) 
            + "\nPosition: "
            + longBuffer.position() 
            + "\nLimit: "
            + longBuffer.limit()); 
  
        // Rewind the Buffer 
        // using rewind() method 
        longBuffer.rewind(); 
  
        // print the buffer 
        System.out.println( 
            "\nBuffer after operation: "
            + Arrays.toString( 
                  longBuffer.array()) 
            + "\nPosition: "
            + longBuffer.position() 
            + "\nLimit: "
            + longBuffer.limit()); 
    } 
}

输出：

Buffer before operation: [10, 20, 30, 0, 0]
Position: 3
Limit: 5

Buffer after operation: [10, 20, 30, 0, 0]
Position: 0
Limit: 5

参考： https://docs.oracle.com/javase/9/docs/api/java/nio/LongBuffer.html#mark–

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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 LongBuffer rewind() 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。