Java IntBuffer clear()方法及示例

Java IntBuffer clear()方法及示例

java.nio.IntBuffer 类的 clear() 方法被用来清除这个缓冲区。在清除这个缓冲区时,会做以下改变。

  • 位置被设置为零
  • 限制被设置为容量
  • 标记被丢弃。

语法

public final IntBuffer clear()
Java

参数: 该方法不接受任何参数。

返回值: 该方法在清除IntBuffer中的所有数据后返回该实例。

下面的例子说明了clear()方法的作用。

例子 1 :

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

输出:

position before reset: 4
position after reset: 0
Java

例子 2 :

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

输出:

position before clear: 3
position after clear: 0
Java

参考资料: https://docs.oracle.com/javase/9/docs/api/java/nio/IntBuffer.html#rewind-

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