Java 中的 Reader markSupported()方法,示例

原文:https://www . geesforgeks . org/reader-marksupported-method-in-Java-with-examples/

Java 中 Reader 类的 markSupported() 方法用来检查这个 Reader 是否支持 mark()操作。它返回一个布尔值,该值表示读取器是否被标记为受支持。

语法:

public boolean markSupported()

参数:该方法不接受任何参数

返回值:这个方法返回一个布尔值,这个值告诉这个阅读器是否支持 mark()操作。如果它是 markSupported,则返回 true。否则返回假。

下面的方法说明了 markSupported()方法的工作原理:

程序 1:

// Java program to demonstrate
// Reader markSupported() method

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String[] args)
    {

        try {

            String str = "GeeksForGeeks";

            // Create a Reader instance
            Reader reader
                = new StringReader(str);

            // Check if the Reader is
            // markSupported using markSupported()
            System.out.println("Is Reader markSupported: "
                               + reader.markSupported());

            reader.close();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出:

Is Reader markSupported: true

程序二:

// Java program to demonstrate
// Reader markSupported() method

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String[] args)
    {

        try {
            char[] str = { 'G', 'E', 'E', 'K', 'S' };

            // Create a Reader instance
            Reader reader
                = new CharArrayReader(str);

            // Check if the Reader is
            // markSupported using markSupported()
            System.out.println("Is Reader markSupported: "
                               + reader.markSupported());

            reader.close();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出:

Is Reader markSupported: true

参考:https://docs . Oracle . com/javase/9/docs/API/Java/io/reader . html # markSupported–