How to read from particular header in opencsv?

Magnilex and Sparky are right in that CSVReader does not support reading values by column name. But that being said there are two ways you can do this.

Given that you have the column names and the default CSVReader reads the header you can search the first the header for the position then use that from there on out;

private int getHeaderLocation(String[] headers, String columnName) {
   return Arrays.asList(headers).indexOf(columnName);
}

so your method would look like (leaving out a lot of error checks you will need to put in)

CSVReader reader = new CSVReader(new FileReader("yourfile.csv"));
String [] nextLine;
int columnPosition;

nextLine = reader.readNext();
columnPosition = getHeaderLocation(nextLine, "castle1");

while ((nextLine = reader.readNext()) != null && columnPosition > -1) {
   // nextLine[] is an array of values from the line
   System.out.println(nextLine[columnPosition]);
}

I would only do the above if you were pressed for time and it was only one column you cared about. That is because openCSV can convert directly to an object that has the variables the same as the header column names using the CsvToBean class and the HeaderColumnNameMappingStrategy.

So first you would define a class that has the fields (and really you only need to put in the fields you want - extras are ignored and missing ones are null or default values).

public class CastleDTO {
   private int id1;
   private String castle1;
   private double salary;
   private String name1;

   // have all the getters and setters here....
}

Then your code would look like

CSVReader reader = new CSVReader(new FileReader("yourfile.csv"));
HeaderColumnNameMappingStrategy<CastleDTO> castleStrategy = new HeaderColumnNameMappingStrategy<CastleDTO>();
CsvToBean<CastleDTO> csvToBean = new CsvToBean<CastleDTO>();

List<CastleDTO> castleList = csvToBean.parse(castleStrategy, reader);

for (CastleDTO dto : castleList) {
   System.out.println(dto.getCastle1());
}

There is no built in functionality in opencsv for reading from a column by name.

The official FAQ example has the following example on how to read from a file:

CSVReader reader = new CSVReader(new FileReader("yourfile.csv"));
String [] nextLine;
while ((nextLine = reader.readNext()) != null) {
   // nextLine[] is an array of values from the line
   System.out.println(nextLine[0] + nextLine[1] + "etc...");
}

You simply fetch the value in second column for each row by accesing the row with nextLine[1] (remember, arrays indices are zero based).

So, in your case you could simply read from the second line:

CSVReader reader = new CSVReader(new FileReader("yourfile.csv"));
String [] nextLine;
while ((nextLine = reader.readNext()) != null) {
   System.out.println(nextLine[1]);
}

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For a more sophisticated way of determining the column index from its header, refer to the answer from Scott Conway.