如何只刪除java中文件的內容？

Question

請問我可以如何刪除java中的文件內容？ 在此先感謝。

Answer 1

如何：

new RandomAccessFile(fileName).setLength(0); 

Answer 2

打開文件進行寫入並保存。它刪除文件的內容。

Answer 3

你可以通過打開文件for writing and then truncating its content做到這一點，下面的例子使用NIO：

import static java.nio.file.StandardOpenOption.*; 

Path file = ...; 

OutputStream out = null; 
try { 
    out = new BufferedOutputStream(file.newOutputStream(TRUNCATE_EXISTING)); 
} catch (IOException x) { 
    System.err.println(x); 
} finally { 
    if (out != null) { 
     out.flush(); 
     out.close(); 
    } 
} 

Another way：截斷剛剛過去的20個字節的文件：

import java.io.RandomAccessFile; 


RandomAccessFile file = null; 
try { 
    file = new RandomAccessFile ("filename.ext","rw"); 
    // truncate 20 last bytes of filename.ext 
    file.setLength(file.length()-20); 
} catch (IOException x) { 
    System.err.println(x); 
} finally { 
    if (file != null) file.close(); 
} 

Answer 4

new FileOutputStream(file, false).close(); 

Answer 5

可能問題是這隻留下頭部我認爲而不是尾巴？

public static void truncateLogFile(String logFile) { 
    FileChannel outChan = null; 
    try { 
     outChan = new FileOutputStream(logFile, true).getChannel(); 
    } 
    catch (FileNotFoundException e) { 
     e.printStackTrace(); 
     System.out.println("Warning Logfile Not Found: " + logFile); 
    } 

    try { 
     outChan.truncate(50); 
     outChan.close(); 
    } 
    catch (IOException e) { 
     e.printStackTrace(); 
     System.out.println("Warning Logfile IO Exception: " + logFile); 
    } 
} 

Answer 6

try { 
     PrintWriter writer = new PrintWriter(file); 
     writer.print(""); 
     writer.flush(); 
     writer.close(); 

    }catch (Exception e) 
    { 

    } 

此代碼將刪除「文件」的當前內容，並設置文件爲0