File arq = new File("C:\Users\EX-PHP\Desktop\ArquivosNfse\xml.xml");

    OkHttpClient client= new OkHttpClient();
    MediaType type = MediaType.parse("application/soap+xml;charset=utf-8");
    RequestBody body = RequestBody.create(type,arq);

    Request request = new Request.Builder()
            .url("http://isscuritiba.curitiba.pr.gov.br/Iss.NfseWebService/Nfsews.asmx")
            .post(body)
            .build();

    Response response = client.newCall(request).execute();
    String res = response.body().string();
    System.out.println(res);

    FileOutputStream out = new FileOutputStream("C:\Users\EX-PHP\Desktop\result.xml");
    out.write(res.getBytes());
    out.close();