writefileaction.java

高级java2 大学教程(含源码,经典的Java学习教程

// WriteFileAction.java
// WriteFileAction is a PrivilegedAction implementation that 
// simply writes a file to the local file system.
package com.deitel.advjhtp1.security.jaas;

// Java core packages
import java.io.*;
import java.security.PrivilegedAction;

public class WriteFileAction implements PrivilegedAction {
   
   // perform the PrivilegedAction
   public Object run() 
   {
      // attempt to write a message to the specified file
      try {
         File file = new File( "D:/", "privilegedFile.txt" );
         FileWriter fileWriter = new FileWriter( file );
         
         // write message to File and close FileWriter
         fileWriter.write( "Welcome to JAAS!" );
         fileWriter.close();
      }
      
      // handle exception writing file
      catch ( IOException ioException ) {
         ioException.printStackTrace();
      }
      
      return null;
      
   } // end method run
}

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