Java Read/Write Fixed Length file sample

public static void TempPreProcessor_Fixed(String input, String output){
 BufferedReader reader = null;
 BufferedWriter writer = null;
 try 
 {
  String inputfilename = input;
  String outputfilename = output;
  
  reader = new BufferedReader(
     new InputStreamReader(
       new FileInputStream(inputfilename)));
  writer = new BufferedWriter(
     new OutputStreamWriter(
       new FileOutputStream(outputfilename)));
  
  String thisLine = null;

  //line 1
  if((thisLine =reader.readLine()) != null) 
   writer.write("AA,"+thisLine+"\n");

  //line 2-4
  for(int i = 0; i<3; i++){
   if((thisLine =reader.readLine()) != null)
    writer.write(thisLine+"\n");
  }
  
  //remaining lines
  while((thisLine=reader.readLine()) != null){   
   //add AB to start of line
   writer.write("AB,"+thisLine+"\n");
   //copy with no change
   if((thisLine=reader.readLine()) != null)
    writer.write(thisLine+"\n");
  } 
 }catch(Exception e){
  throw new ServiceException("TempPreProcessor: Unknown errors: " + e.toString());
 }finally{
  try{
   if(writer != null) writer.flush();
   if(reader != null) reader.close();
   if(writer != null) writer.close();
   reader=null; writer=null;
  }catch(Exception e){
   throw new ServiceException("TempPreProcessor: Unknown errors: " + e.toString());
  }
 }
}

Java Read/Write CSV file sample

public static void TempPreProcessor_CSV(String input, String output){
 //IDataSharedCursor idc = pipeline.getSharedCursor();
 BufferedReader reader = null;
 BufferedWriter writer = null;
 try 
 {
  String inputfilename = input;
  String outputfilename = output;

  reader = new BufferedReader(
               new InputStreamReader(
                   new FileInputStream(inputfilename)));
  writer = new BufferedWriter(
               new OutputStreamWriter(
                   new FileOutputStream(outputfilename)));
  int lineNum = 1;
  String checkNum = "";
  
  String thisLine = "";

  // comma, which is not enclosed in quotes
  String delims = ",(?=([^\"]*\"[^\"]*\")*[^\"]*$)";

  while((thisLine=reader.readLine()) != null){// till end of file
     StringBuffer sb = new StringBuffer();
     if(thisLine.trim().equals("")) 
                           continue; // ignore blank lines
   
     if (lineNum++ == 1){
      sb.append(thisLine + "\n");
      writer.write(sb.toString());
      continue;  
     }

     String[] thisTokens = thisLine.split(delims);                           
     if (!checkNum.equalsIgnoreCase(thisTokens[0].toString())){
         checkNum = thisTokens[0].toString();
         sb.append("AA," + thisLine);
     }else{
         sb.append("AB," + thisLine);
     }
     sb.append("\n");
     writer.write(sb.toString());
  }
 }catch(Exception e){
  //throw new ServiceException(
  //  "TempPreProcessor: Unknown errors: " + e.toString());
 }finally{
  try {
   if(writer != null) writer.flush();
   if(reader != null) reader.close();
   if(writer != null) writer.close();
   reader=null;
   writer=null;
   //idc.destroy();
  }catch(Exception e){
   //throw new ServiceException(
   //  "TempPreProcessor: Unknown errors: " + e.toString());
  }
 }
}

Java Date Format

public static String parseDate(String inDate, String fmFormat, String toFormat){
        SimpleDateFormat fmFormatter = new SimpleDateFormat(fmFormat);
        SimpleDateFormat toFormatter = new SimpleDateFormat(toFormat);
        if ( inDate == null ) return "";  // To avoid java.lang.NullPointerException
        if ( inDate.length() == 0 ) return ""; // Taking care of empty string.
        Date fromDate = null;
        try {
         fromDate = (Date) fmFormatter.parse(inDate);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return  toFormatter.format(fromDate);
}

Java Switch Statement

int boolInt=1;
switch (boolInt){
case 0: System.out.println("true = 0"); break;
case 1: System.out.println("false = 1"); break;
default: System.out.println("Invalid"); break;
}

// In Java SE 7 and later, you can use a String object in the switch statement's expression
String boolStr = "true";
switch (boolStr.toLowerCase()){
case "true": System.out.println("0 = true"); break;
case "false": System.out.println("1 = false"); break;
default: System.out.println(" Not 0/1 = false"); break;
}