怎么修改jar包里的xml文件

static Properties readJarProperty() throws IOException {
  currentJarPath = URLDecoder.decode(com.taisys.ota.util.RunMain.class
    .getProtectionDomain().getCodeSource().getLocation().getFile(),"UTF-8"); // 获取当前Jar文件名，并对其解码，防止出现中文乱码
  System.out.println("currentJarPath=" + currentJarPath);
  JarFile currentJar = new JarFile(currentJarPath);

  JarEntry dbEntry = currentJar
    .getJarEntry("com/taisys/ota/util/jdbc.properties");
  InputStream in = currentJar.getInputStream(dbEntry);
  Properties p = new Properties();
  p.load(in);

  in.close();
  return p;

 }

 static void updateJarProperty() throws IOException {
  currentJarPath = URLDecoder.decode(com.taisys.ota.util.RunMain.class
    .getProtectionDomain().getCodeSource().getLocation().getFile(),"UTF-8"); // 获取当前Jar文件名，并对其解码，防止出现中文乱码
  String EntryName = "jdbc.properties";
  currentPath = startServer();
  byte[] data = null;
  File properFile = new File(currentPath + "/jdbc.properties");
  if (properFile.exists()) {
   InputStream in = new FileInputStream(properFile);
   data = getByte(in);
  }
  try {
   JarFile jf = new JarFile(currentJarPath);
   TreeMap<String,byte[]> tm = new TreeMap<String,byte[]>();
   Enumeration es = jf.entries();
   while (es.hasMoreElements()) {
    JarEntry je = (JarEntry) es.nextElement();
    byte[] b = getByte(jf.getInputStream(je));
    tm.put(je.getName(),b);
   }
   JarOutputStream out = new JarOutputStream(new FileOutputStream(
     currentJarPath));
   Set set = tm.entrySet();
   Iterator it = set.iterator();
   boolean has = false;
   while (it.hasNext()) {
    Map.Entry me = (Map.Entry) it.next();
    String name = (String) me.getKey();
    JarEntry jeNew = new JarEntry(name);
    // System.out.println("jeNew.getName()="+jeNew.getName());
    out.putNextEntry(jeNew);
    byte[] b;
    if (name.equals(EntryName)) {
     b = data;
     has = true;
    } else
     b = (byte[]) me.getValue();
    out.write(b,b.length);
   }
   if (!has) {
    JarEntry jeNew = new JarEntry(EntryName);
    out.putNextEntry(jeNew);
    out.write(data,data.length);
   }
   out.flush();
   out.finish();
   out.close();
  } catch (Exception e) {
   e.printStackTrace();
  }

 }