Java利用正则表达式提取数据的方法

1300102,北京市
1300103,北京市
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1300108,北京市
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1300110,北京市
1300111,北京市
1300112,北京市
1300113,北京市
1300114,北京市
1300115,北京市
1300116,北京市
1300117,北京市
1300118,北京市
1300119,北京市

public static void main(String args[]) {
  File file = null;
  BufferedReader br = null;
  StringBuffer buffer = null;
  String childPath = "src/endlist.txt";
  String data = "";
  try {
   file = new File(childPath);
   buffer = new StringBuffer();
   InputStreamReader isr = new InputStreamReader(new FileInputStream(file), "utf-8");
   br = new BufferedReader(isr);
   int s;
   while ((s = br.read()) != -1) {
    buffer.append((char) s);
   }
   data = buffer.toString();
  } catch (Exception e) {
   e.printStackTrace();
  }
  Map<String, ArrayList<String>> resultMap = new HashMap<String, ArrayList<String>>();
  for (int i = 0; i < 10; i++) {
   resultMap.put("13" + i, new ArrayList<String>());
  }
  Pattern pattern = Pattern.compile("(\\d{3})(\\d{4},[\u4e00-\u9fa5]*\\n)");
  Matcher matcher = pattern.matcher(data); 
  while (matcher.find()) {
   resultMap.get(matcher.group(1)).add(matcher.group(2));
  }
  for (int i = 0; i < 10; i++) {
   if (resultMap.get("13" + i).size() > 0) {
    try {
     File outFile = new File("src/13" + i + ".txt");
     FileOutputStream outputStream = new FileOutputStream(outFile);
     OutputStreamWriter writer = new OutputStreamWriter(outputStream, "utf-8");
     ArrayList<String> tempList = resultMap.get("13" + i);
     for (int j = 0; j < tempList.size(); j++) {
      writer.append(resultMap.get("13" + i).get(j));
     }
     writer.close();
     outputStream.close();
    } catch (Exception e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
   }
  }
 }