安卓文件寫入與讀取

讀寫/data/data/<應用程序名>目錄上的文件:

//寫數據  
public void writeFile(String fileName,String writestr) throws IOException{   
  try{   
        FileOutputStream fout =openFileOutput(fileName, MODE_PRIVATE);   

        byte [] bytes = writestr.getBytes();   

        fout.write(bytes);   

        fout.close();   
      }   

        catch(Exception e){   
        e.printStackTrace();   
       }   
}   

//讀數據  
public String readFile(String fileName) throws IOException{   
  String res="";   
  try{   
         FileInputStream fin = openFileInput(fileName);   
         int length = fin.available();   
         byte [] buffer = new byte[length];   
         fin.read(buffer);       
         res = EncodingUtils.getString(buffer, "UTF-8");   
         fin.close();       
     }   
     catch(Exception e){   
         e.printStackTrace();   
     }   
     return res;   

}     

從resource的asset中讀取文件數據

String fileName = "test.txt"; //文件名字   
String res="";   
try{   

   //得到資源中的asset數據流  
   InputStream in = getResources().getAssets().open(fileName);   

   int length = in.available();           
   byte [] buffer = new byte[length];          

   in.read(buffer);              
   in.close();  
   res = EncodingUtils.getString(buffer, "UTF-8");       

  }catch(Exception e){   

      e.printStackTrace();           

   }  

從resource的raw中讀取文件數據

String res = "";   
try{   

    //得到資源中的Raw數據流  
    InputStream in = getResources().openRawResource(R.raw.test);   

    //得到數據的大小  
    int length = in.available();         

    byte [] buffer = new byte[length];          

    //讀取數據  
    in.read(buffer);           

    //依test.txt的編碼類型選擇合適的編碼，如果不調整會亂碼   
    res = EncodingUtils.getString(buffer, "BIG5");   

    //關閉      
    in.close();              

   }catch(Exception e){   
      e.printStackTrace();           
   }   

讀寫SD卡中的文件。也就是/mnt/sdcard/目錄下面的文件

//寫數據到SD中的文件  
public void writeFileSdcardFile(String fileName,String write_str) throws IOException{   
 try{   

       FileOutputStream fout = new FileOutputStream(fileName);   
       byte [] bytes = write_str.getBytes();   

       fout.write(bytes);   
       fout.close();   
     }  

      catch(Exception e){   
        e.printStackTrace();   
       }   
   }   


//讀SD中的文件  
public String readFileSdcardFile(String fileName) throws IOException{   
  String res="";   
  try{   
         FileInputStream fin = new FileInputStream(fileName);   

         int length = fin.available();   

         byte [] buffer = new byte[length];   
         fin.read(buffer);       

         res = EncodingUtils.getString(buffer, "UTF-8");   

         fin.close();       
        }   

        catch(Exception e){   
         e.printStackTrace();   
        }   
        return res;   
}   

使用File類進行文件的讀寫

//讀文件  
public String readSDFile(String fileName) throws IOException {    

        File file = new File(fileName);    

        FileInputStream fis = new FileInputStream(file);    

        int length = fis.available();   

         byte [] buffer = new byte[length];   
         fis.read(buffer);       

         res = EncodingUtils.getString(buffer, "UTF-8");   

         fis.close();       
         return res;    
}    

//寫文件  
public void writeSDFile(String fileName, String write_str) throws IOException{    

        File file = new File(fileName);    

        FileOutputStream fos = new FileOutputStream(file);    

        byte [] bytes = write_str.getBytes();   

        fos.write(bytes);   

        fos.close();   
     ｝