将文件内容准换为unicode码内容文件（java实现）

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.BufferedReader;
import java.io.File;
import java.io.BufferedWriter;
import java.io.IOException;
import java.util.Scanner;

public class TranslateToUnicodeJava
{
public static void main(String args[]) throws IOException
{
Scanner in = new Scanner(System.in);
System.out.println("请输入已存在的文件名：");
String fileName = in.nextLine();
File f = new File("./"+fileName);
if(!f.exists())
{
System.out.println("文件："+fileName+"不存在！");
System.exit(0);
}
BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(f)));
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("c:/users/xiuye/desktop/"+fileName)));
int i=-1;
String str="";
String unicodeOriginal="";
String unicodeTemp = "";
while((i=br.read())!=-1)
{
unicodeOriginal = Integer.toHexString(i);
int length = unicodeOriginal.length();
if(length==1)
{
unicodeTemp="000"+unicodeOriginal;
}
else if(length==2)
{
unicodeTemp="00"+unicodeOriginal;
}
else if(length == 3)
{
unicodeTemp="0"+unicodeOriginal;
}
else{
unicodeTemp = unicodeOriginal;
}
str="\\u"+unicodeTemp;
bw.write(str,0,str.length());
bw.flush();
System.out.print("\\u"+unicodeTemp);

}

br.close();
bw.close();
in.close();

}
}