java去重工具类

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class TT {
public void go(String file,String dirfile){
List m=new ArrayList();
try {
BufferedReader br = new BufferedReader(new FileReader(new File(file)));
StringBuffer sb = new StringBuffer();
String line = br.readLine();
while (line != null) {
m.add(line);
line = br.readLine();
}
br.close();
} catch (IOException e) {
e.printStackTrace();
}
System.out.println(m.size());

Map map=new HashMap();
for(int i=0;i<m.size();i++){
if(!map.containsKey(m.get(i))){
map.put(m.get(i),"1");
}
}

OutputStream os;
try {
os = new FileOutputStream(dirfile);
PrintWriter pw = new PrintWriter(new OutputStreamWriter(os, "utf-8"), true);

Iterator iter = map.entrySet().iterator();
while (iter.hasNext()) {
Map.Entry entry = (Map.Entry) iter.next();
Object key = entry.getKey();
pw.println(key);
System.out.println(key);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

public static void main(String[] args) {
// TODO Auto-generated method stub
new TT().go("c://qq.txt","c://qqee.txt");
}
}