Java PushbackReader markSupported()用法及代碼示例

Java中PushbackReader類的markSupported()方法用於檢查此PushbackReader是否支持mark()操作。它返回一個布爾值，該狀態指示是否標記了閱讀器。

用法:

public boolean markSupported()

參數：此方法不接受任何參數

返回值：此方法返回一個布爾值，該值指示此PushbackReader是否支持mark()操作。如果為markSupported，則返回true。否則返回false。

下麵的方法說明了markSupported()方法的用法方式：

示例1:

// Java program to demonstrate 
// PushbackReader markSupported() method 
  
import java.io.*; 
import java.util.*; 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        try { 
            // Initializing a StringReader 
            // and PushbackReader 
            String s = "GeeksForGeeks"; 
  
            StringReader stringReader 
                = new StringReader(s); 
            PushbackReader pushbackReader 
                = new PushbackReader(stringReader); 
  
            // check if the mark() method 
            // is supported or not 
            System.out.println("Is mark() supported:"
                               + pushbackReader.markSupported()); 
  
            // Close the stream using markSupported() 
            pushbackReader.close(); 
            System.out.println("Stream Closed."); 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
}

輸出：

Is mark() supported:false
Stream Closed.

示例2:

// Java program to demonstrate 
// PushbackReader markSupported() method 
  
import java.io.*; 
import java.util.*; 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        try { 
            // Initializing a StringReader 
            // and PushbackReader 
            String s = "GFG"; 
  
            StringReader stringReader 
                = new StringReader(s); 
            PushbackReader pushbackReader 
                = new PushbackReader(stringReader); 
  
            // check if the mark() method 
            // is supported or not 
            System.out.println("Is mark() supported:"
                               + pushbackReader.markSupported()); 
  
            // Close the stream 
            pushbackReader.close(); 
            System.out.println("Stream Closed."); 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
}

輸出：

Is mark() supported:false
Stream Closed.

參考： https://docs.oracle.com/javase/9/docs/api/java/io/PushbackReader.html#markSupported–

相關用法

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