JAVA - 非可寫通道異常

public FileProcessor(String filenameIn, String fileModeIn){ 
     try { 
      randomaccessfile = new RandomAccessFile(filenameIn, fileModeIn); 
      fileChannel = randomaccessfile.getChannel(); 
      buffer = fileChannel.map(FileChannel.MapMode.READ_WRITE, 0, fileChannel.size()); 
     } catch (FileNotFoundException e) { 
      System.err.println("Error while creating a File"); 
      e.printStackTrace(); 
      System.exit(1); 
     } catch (IOException e) { 
      System.err.println("Error while creating MappedByteBuffer"); 
      e.printStackTrace(); 
      System.exit(1); 
     }

異常線程「main」 java.nio.channels.NonWritableChannelException 在sun.nio.ch.FileChannelImpl.map（FileChannelImpl.java:880）JAVA - 非可寫通道異常

獲取NonwritableChannelException爲上面的代碼。請幫忙。謝謝。！！

來源

2016-11-14 ShreyasMN

什麼是你的fileModeIn？ – developer

我得到一個文件模式作爲輸入，但默認設置爲READ_WRITE – ShreyasMN

當我的最後一個小型可重複程序在fileModeIn和FileChannel.MapMode.READ_WRITE不匹配的時候出現錯誤。

樣例程序：

import java.io.*; 
import java.nio.channels.*; 
import java.nio.MappedByteBuffer; 
class SampleFileProcessor { 
    public static void main(String[] args) { 
     String fileName = args[0]; 
     String mode = args[1]; 
     JFP jf = new JFP(); 
     jf.FileProcessor(fileName,mode); 
    } 

    public void FileProcessor(String filenameIn, String fileModeIn){ 
     try { 
      RandomAccessFile randomaccessfile = new RandomAccessFile(filenameIn, fileModeIn); 
      FileChannel fileChannel = randomaccessfile.getChannel(); 
      MappedByteBuffer buffer = fileChannel.map(FileChannel.MapMode.READ_WRITE, 0, fileChannel.size()); 
     } catch (FileNotFoundException e) { 
      System.err.println("Error while creating a File"); 
      e.printStackTrace(); 
      System.exit(1); 
     } catch (IOException e) { 
      System.err.println("Error while creating MappedByteBuffer"); 
      e.printStackTrace(); 
      System.exit(1); 
     } 
    } 
}

輸入輸出&：

echo "Non-matching fileModeIn and FileChannel.MapMode" 
java SampleFileProcessor input_file.txt r 
Exception in thread "main" java.nio.channels.NonWritableChannelException 
    at sun.nio.ch.FileChannelImpl.map(FileChannelImpl.java:799) 
    at JFP.FileProcessor(JFP.java:19) 
    at JFP.main(JFP.java:9) 
<Error> 

echo "Matching fileModeIn and FileChannel.MapMode" 
java SampleFileProcessor input_file.txt rw 
<Success>

來源

2016-11-15 01:25:06 learningloop

如果你想READ_WRITE映射文件，當您創建RandomAccessFile你最終從得到它時需要"rw" ..

來源

2016-11-15 01:52:46 EJP

JAVA - 非可寫通道異常

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