Java 中的 IntBuffer 标记()方法,示例

原文:https://www . geesforgeks . org/int buffer-mark-method-in-Java-with-examples/

java.nio.IntBuffer 类标记()方法用于将该 IntBuffer 的当前位置标记为该缓冲区的标记。

语法:

public final IntBuffer mark()

参数:该方法不取任何参数。

返回值:在当前位置设置缓冲区标记后,该方法返回该 IntBuffer。

下面是说明 mark()方法的示例:

示例 1:

// Java program to demonstrate
// mark() method

import java.nio.*;
import java.util.*;

public class GFG {

    public static void main(String[] args)
    {

        try {

            int[] farr = { 10, 20, 30, 40 };

            // creating object of IntBuffer
            // and allocating size capacity
            IntBuffer ib = IntBuffer.wrap(farr);

            // 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 reset() to restore
            // to the position we marked
            ib.reset();

            // display position
            System.out.println("position after reset: "
                               + ib.position());
        }

        catch (InvalidMarkException e) {
            System.out.println("New position "
                               + "is less than "
                               + "the position "
                               + "marked before ");
            System.out.println("Exception throws: "
                               + e);
        }
    }
}

输出:

position before reset: 4
position after reset: 2

示例 2: 演示无效标记异常

// Java program to demonstrate
// mark() method

import java.nio.*;
import java.util.*;

public class GFG {

    public static void main(String[] args)
    {

        try {

            int[] farr = { 10, 20, 30, 40 };

            // creating object of IntBuffer
            // and allocating size capacity
            IntBuffer ib = IntBuffer.wrap(farr);

            // 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 1
            ib.position(1);

            // display position
            System.out.println("position before reset: "
                               + ib.position());

            // try to call reset() to restore
            // to the position we marked
            ib.reset();

            // display position
            System.out.println("position after reset: "
                               + ib.position());
        }

        catch (InvalidMarkException e) {
            System.out.println("\nNew position "
                               + "is less than "
                               + "the position "
                               + "marked before ");
            System.out.println("Exception throws: "
                               + e);
        }
    }
}

输出:

position before reset: 1

New position is less than the position marked before 
Exception throws: java.nio.InvalidMarkException

参考:https://docs . Oracle . com/javase/9/docs/API/Java/nio/intbuffer . html # mark–