Java Buffer hasRemaining()方法及示例

java.nio.Buffer 类的 hasRemaining() 方法是用来告诉人们在当前位置和极限之间是否有任何元素。

语法

public final boolean hasRemaining()

返回： 当且仅当这个缓冲区中至少有一个元素剩余时，该方法将返回 true 。下面是说明 hasRemaining() 方法的例子。

例1 :

// Java program to demonstrate
// hasRemaining() method
 
import java.nio.*;
import java.util.*;
 
public class GFG {
    public static void main(String[] args)
    {
 
        // Declaring the capacity of the ByteBuffer
        int capacity = 10;
 
        // creating object of bytebuffer
        // and allocating size capacity
        ByteBuffer bb = ByteBuffer.allocate(capacity);
 
        // putting the value in bytebuffer
        bb.put((byte)10);
        bb.put((byte)20);
        bb.rewind();
 
        // Typecast bytebuffer to Buffer
        Buffer buffer = (Buffer)bb;
 
        // checking if, there is at least one element
        // remaining in this buffer.
        boolean isRemain = buffer.hasRemaining();
 
        // checking if else condition
        if (isRemain)
            System.out.println("there is at least one "
                               + "element remaining "
                               + "in this buffer");
        else
            System.out.println("there is no "
                               + "element remaining "
                               + "in this buffer");
    }
}

输出

there is at least one element remaining in this buffer

例2 :

// Java program to demonstrate
// hasRemaining() method
 
import java.nio.*;
import java.util.*;
 
public class GFG {
    public static void main(String[] args)
    {
 
        // Declaring the capacity of the ByteBuffer
        int capacity = 0;
 
        // creating object of bytebuffer
        // and allocating size capacity
        ByteBuffer bb = ByteBuffer.allocate(capacity);
 
        // Typecast bytebuffer to Buffer
        Buffer buffer = (Buffer)bb;
 
        // checking buffer is backed by array or not
        boolean isRemain = buffer.hasRemaining();
 
        // checking if else condition
        if (isRemain)
            System.out.println("there is at least one "
                               + "element remaining"
                               + " in this buffer");
        else
            System.out.println("there is no "
                               + "element remaining"
                               + " in this buffer");
    }
}

输出

there is no element remaining in this buffer