Java LongBuffer clear()用法及代码示例

java.nio.LongBuffer类的clear()方法用于清除此缓冲区。在清除此缓冲区时，需要进行以下更改：

位置设置为零
限制设置为容量
商标被丢弃。

用法:

public final LongBuffer clear()

参数：该方法不带任何参数。

返回值：从其中清除所有数据后，此方法将返回此LongBuffer实例。

下面是说明clear()方法的示例：

范例1：

// Java program to demonstrate 
// clear() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        try { 
  
            long[] arr = { 10, 20, 30, 40 }; 
  
            // creating object of LongBuffer 
            // and allocating size capacity 
            LongBuffer lb 
                = LongBuffer.wrap(arr); 
  
            // try to set the position at index 2 
            lb.position(2); 
  
            // Set this buffer mark position 
            // using mark() method 
            lb.mark(); 
  
            // try to set the position at index 4 
            lb.position(4); 
  
            // display position 
            System.out.println("position before reset: "
                               + lb.position()); 
  
            // try to call clear() to restore 
            // to the position at index 0 
            // by discarding the mark 
            lb.clear(); 
  
            // display position 
            System.out.println("position after reset: "
                               + lb.position()); 
        } 
  
        catch (InvalidMarkException e) { 
            System.out.println("new position is less than "
                               + "the position we "
                               + "marked before "); 
            System.out.println("Exception throws: " + e); 
        } 
    } 
}

输出：

position before reset: 4
position after reset: 0

范例2：

// Java program to demonstrate 
// clear() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        long[] arr = { 10, 20, 30, 40 }; 
  
        // creating object of LongBuffer 
        // and allocating size capacity 
        LongBuffer lb = LongBuffer.wrap(arr); 
  
        // try to set the position at index 3 
        lb.position(3); 
  
        // display position 
        System.out.println("position before clear: "
                           + lb.position()); 
  
        // try to call clear() to restore 
        // to the position at index 0 
        // by discarding the mark 
        lb.clear(); 
  
        // display position 
        System.out.println("position after clear: "
                           + lb.position()); 
    } 
}

输出：

position before clear: 3
position after clear: 0

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

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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 clear() 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。