java依据 字段删除重复的数据

java根据 字段删除重复的数据
现在有这么一个问题：
Name,CardNo,Descriot,CtfTp,CtfId,Gender,Birthday,Address
彬,,,ID,xxxxx21059,M,20101001,,,F,,CHN,,,,,,,,139,19:46:02,4000000
珊,,,ID,xxxxx811090189,M,20101001,,,F,,CHN,,,,,,,,158
世,,,ID,4xxxxx1772,M,19880129,,,F,,CHN,,,,,,,,152108,2,1,,,,,0,2010-10-19 
超,,,ID,4xxxxx1772,M,20101001,,,F,,CHN,,,,,,,,1585091,,,mc06o.cn,,,,,,,,0,2010-10-19 19:46:04,4000003
磊,,,ID,4xxxxx1772,M,19831011,,,F,,CHN,,,,,,,,159159,362,,565408,,,,,,,,0,2010-10-19 19:46:05,4000004
芳,,,ID,xxxxx811090189,M,20101001,,,F,,CHN,,,,,,,,1506:05,4005
读取文件后，我要根据CtfTp 字段对应 的字段，删除掉重复的。
比如4xxxxx1772 有几个重复的，我要根据CtfTp将重复的删掉。
------解决方案--------------------
发现用Excel写代码也不错,至少对的起

import java.io.*;
import java.util.*;

public class TestMain {

	public static void main(String[] args) {
		
		ArrayList<HashMap<String, String>> rowList = readCsv("c:\\csv.csv");
		ArrayList<HashMap<String, String>> distinctRowList = new ArrayList<HashMap<String,String>>();

		HashMap<String, HashMap<String, String>> keyRowList = new HashMap<String, HashMap<String,String>>();
		for (Iterator<HashMap<String, String>> iterator = rowList.iterator(); iterator.hasNext();) {
			HashMap<String, String> currentRow =  iterator.next();
			try{
				keyRowList.put(currentRow.get("CtfTp"), currentRow);
			}catch(Exception e){	
			}
		}
		
		for (HashMap<String, String> hashMap : keyRowList.values()) {
			distinctRowList.add(hashMap);
		}
		
		writeCsv(distinctRowList, "c:\\csv.csv");
	}
	
	private static ArrayList<HashMap<String, String>> readCsv(String fileName) {
		ArrayList<HashMap<String, String>> retList = new ArrayList<HashMap<String,String>>();
		String[] keys = new String[8];
		File csv = null;
		BufferedReader br = null;
		try { 
            csv = new File(fileName);

            br = new BufferedReader(new FileReader(csv)); 

            String line = "";
            int lineIndex = 0;
			while ((line = br.readLine()) != null) {
				String[] cells = line.split(",");
				if (lineIndex > 0) {
					HashMap<String, String> row = new HashMap<String, String>();
					for (int i = 0; i < keys.length; i++) {
						row.put(keys[i], cells[i]);
					}
					retList.add(row);
				} else {
					for (int i = 0; i < keys.length; i++) {
						keys[i]=cells[i];
					}
				}
				lineIndex++;
            } 
        } catch (Exception e) { 
            e.printStackTrace(); 
        } finally {
        	if (br!=null) {
				try {
					br.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
        }
		return retList;
	}
	
	private static void writeCsv(ArrayList<HashMap<String, String>> data, String fileName){
		File csv = null;
		BufferedWriter bw = null;
		try { 
            csv = new File(fileName);
            if (csv.exists()) {
				csv.delete();
			}
			bw = new BufferedWriter(new FileWriter(csv, false));
			bw.newLine();
			bw.write("Name,CardNo,Descriot,CtfTp,CtfId,Gender,Birthday,Address");
			for (Iterator<HashMap<String, String>> iterator = data.iterator(); iterator
					.hasNext();) {
				HashMap<String, String> currentRow = iterator.next();
				bw.newLine();
				bw.write(String.format("%s,%s,%s,%s,%s,%s,%s,%s",
						currentRow.get("Name"), currentRow.get("CardNo"),
						currentRow.get("Descriot"), currentRow.get("CtfTp"),
						currentRow.get("CtfId"), currentRow.get("Gender"),
						currentRow.get("Birthday"), currentRow.get("Address")));
			}
        } catch (Exception e) { 
            e.printStackTrace(); 
        } finally {
        	if(bw !=null){
        		try {