安卓与java后台信息交互

安卓通过浏览器访问java发布在tomcat的地址并传值：http://localhost:8080/jinyi-backgmanage/download/down?versionNumber=201708041048，java后台接受网址传过来的值进行判断，怎么把信息返回给安卓？

response.setCharacterEncoding("utf-8");
response.write("要返回的信息");

后台响应的命令
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.print("responseData");
用response.write也可以
安卓端获取到的后台传的字符串值 responseData，
response = client.newCall(request).execute();
responseData_1 = response.body().string();
Log.e("responseData_1----",""+responseData_1);