正则表达式匹配中文后写入txt文件

匹配中文的正则表达式：[\u4e00-\u9fa5]

public class GetChinese {
	public static void main(String[] args) throws IOException {
		File f = new File("in.txt");
		File out = new File("out.txt");
		Pattern pattern = Pattern.compile("[\u4e00-\u9fa5]");
		BufferedReader br = new BufferedReader(new FileReader(f));
		BufferedWriter bw = new BufferedWriter(new FileWriter(out));
		String s = null;
		while((s = br.readLine())!=null){
			Matcher matcher = pattern.matcher(s);
			while(matcher.find()){
				bw.write(matcher.group());
			}
			bw.newLine();
			bw.flush();
		}
	}
}