How to escape comma and double quote at same time for CSV file?

Solution 1:

There are several libraries. Here are two examples:

❐ Apache Commons Lang

Apache Commons Lang includes a special class to escape or unescape strings (CSV, EcmaScript, HTML, Java, Json, XML): org.apache.commons.lang3.StringEscapeUtils.

• Escape to CSV

  String escaped = StringEscapeUtils
      .escapeCsv("I said \"Hey, I am 5'10\".\""); // I said "Hey, I am 5'10"."
  
  System.out.println(escaped); // "I said ""Hey, I am 5'10""."""
  

• Unescape from CSV

  String unescaped = StringEscapeUtils
      .unescapeCsv("\"I said \"\"Hey, I am 5'10\"\".\"\"\""); // "I said ""Hey, I am 5'10""."""
  
  System.out.println(unescaped); // I said "Hey, I am 5'10"."
  

_{* You can download it from here.}

❐ OpenCSV

If you use OpenCSV, you will not need to worry about escape or unescape, only for write or read the content.

• Writing file:

  FileOutputStream fos = new FileOutputStream("awesomefile.csv"); 
  OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF-8");
  CSVWriter writer = new CSVWriter(osw);
  ...
  String[] row = {
      "123", 
      "John", 
      "Smith", 
      "39", 
      "I said \"Hey, I am 5'10\".\""
  };
  writer.writeNext(row);
  ...
  writer.close();
  osw.close();
  os.close();
  

• Reading file:

  FileInputStream fis = new FileInputStream("awesomefile.csv"); 
  InputStreamReader isr = new InputStreamReader(fis, "UTF-8");
  CSVReader reader = new CSVReader(isr);
  
  for (String[] row; (row = reader.readNext()) != null;) {
      System.out.println(Arrays.toString(row));
  }
  
  reader.close();
  isr.close();
  fis.close();
  

_{* You can download it from here.}

Solution 2:

Excel has to be able to handle the exact same situation.

Put those things into Excel, save them as CSV, and examine the file with a text editor. Then you'll know the rules Excel is applying to these situations.

Make Java produce the same output.

The formats used by Excel are published, by the way...

****Edit 1:**** Here's what Excel does
****Edit 2:**** Note that php's fputcsv does the same exact thing as excel if you use " as the enclosure.

[email protected]
Richard
"This is what I think"

gets transformed into this:

Email,Fname,Quoted  
[email protected],Richard,"""This is what I think"""

Solution 3:

Thanks to both Tony and Paul for the quick feedback, its very helpful. I actually figure out a solution through POJO. Here it is:

if (cell_value.indexOf("\"") != -1 || cell_value.indexOf(",") != -1) {
    cell_value = cell_value.replaceAll("\"", "\"\"");
    row.append("\"");
    row.append(cell_value);
    row.append("\"");
} else {
    row.append(cell_value);
}

in short if there is special character like comma or double quote within the string in side the cell, then first escape the double quote("\"") by adding additional double quote (like "\"\""), then put the whole thing into a double quote (like "\""+theWholeThing+"\"" )