在android手机端写了个程序，功能是完成一个两位数的运算。这个运算过程是在java后台完成的，android端利用Http通信把相关的参数传过去，后台经过计算把结果返回给客户端。
贴出客户端部分代码
//点击按钮，把参数打包成json格式发送到后台
public void send(View v){ String str1 = tv1.getText().toString(); String str2 = tv2.getText().toString(); if(str1.equals("") || str2.equals("")){ Toast.makeText(MainActivity.this, "参数不能为空!", Toast.LENGTH_LONG).show(); return; } final int a = Integer.parseInt(str1); final int b = Integer.parseInt(str2); new Thread(new Runnable() { @Override public void run() { JSONObject jsonObject = new JSONObject(); JSONArray jsonArray = new JSONArray(); try { jsonObject.put("parm1", a + ""); jsonObject.put("parm2", b + ""); jsonArray.put(jsonObject); } catch (JSONException e) { e.printStackTrace(); }result = new HttpUtils().getDataFromServer(Consant.url, jsonArray.toString(), method, a, b);mHandler.sendEmptyMessage(0x0001);}}).start();} //在这里我同时进行两种方式的参数传递
//一个是setRequestProperty(key, value);
//另一个是常用的输出流
/**
* 根据手机号从服务器获取相关信息
* 从服务器上获取指定的内容-POST
*
*/
public String getDataFromServer(String svrUrl, String ParamStr, String type, int a, int b) {try { // 转成指定格式 byte[] requestData = ParamStr.getBytes("UTF-8"); HttpURLConnection conn = null; DataOutputStream outStream = null; String MULTIPART_FORM_DATA = "multipart/form-data"; // 构造一个post请求的http头 URL url = new URL(svrUrl); // 服务器地址 conn = (HttpURLConnection) url.openConnection(); conn.setDoInput(true); // 允许输入 conn.setDoOutput(true); // 允许输出 conn.setUseCaches(false); // 不使用caches conn.setRequestMethod("POST"); conn.setRequestProperty("Connection", "Keep-Alive"); conn.setRequestProperty("Content-Type", MULTIPART_FORM_DATA); conn.setRequestProperty("Content-Length", Long.toString(requestData.length)); conn.setRequestProperty("method", type); conn.setRequestProperty("one", a + ""); conn.setRequestProperty("two", b + ""); // 请求参数内容, 获取输出到网络的连接流对象 outStream = new DataOutputStream(conn.getOutputStream()); outStream.write(requestData, 0, requestData.length); outStream.flush(); outStream.close(); ByteArrayOutputStream outStream2 = new ByteArrayOutputStream(); int cah = conn.getResponseCode(); if (cah != 200) { Log.v("data", "服务器响应错误代码:" + cah); return "0"; }else if(cah == 200){ Log.v("data", "服务器响应成功:" + cah); } InputStream inputStream = conn.getInputStream(); int len = 0; byte[] data = new byte[1024]; while ((len = inputStream.read(data)) != -1) { outStream2.write(data, 0, len); } outStream2.close(); inputStream.close(); String responseStr = new String(outStream2.toByteArray()); Log.v("data", "data = " + responseStr); return responseStr;} catch (Exception e) { return "";}} 接下来看看java服务端处理
//在java web项目中创建了一个Servlet用来接收客户端发送的数据
//因为客户端用的是Post方法，所以我们在Servlet的Post方法中对数据进行处理
//客户端用了两种方式传参数，在后台我们仍然用两种方式取参数
//第一种 String method = request.getHeader("method").toString();
//第二种则是输出流来取值了
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("---------00000000----"); int a; int b; int res = 0; double res2 = 0; String result; String method = request.getHeader("method").toString(); String str1 = request.getHeader("one").toString(); String str2 = request.getHeader("two").toString(); System.out.println(method + "/" + str1 + "/" + str2); try{ a = Integer.parseInt(str1); b = Integer.parseInt(str2); }catch(Exception e){ response.getWriter().append(e.getMessage() + ""); return; } if(method.equals("+")){ res = new Utils().plus(a, b); }else if(method.equals("-")){ res = new Utils().minus(a, b); }else if(method.equals("*")){ res = new Utils().multy(a, b); }else if(method.equals("/")){ res2 = new Utils().trad(a, b); } if(method.equals("/")){ result = res2 + ""; }else{ result = res + ""; } response.setCharacterEncoding("utf-8"); response.getWriter().append(result + ""); getData(request);} public String getData(HttpServletRequest req){ String result = null; try { //包装request的输入流 BufferedReader br = new BufferedReader( new InputStreamReader((ServletInputStream) req.getInputStream(), "utf-8")); //缓冲字符 StringBuffer sb=new StringBuffer(""); String line; while((line=br.readLine())!=null){ sb.append(line); } br.close();//关闭缓冲流 result=sb.toString();//转换成字符 System.out.println("result = " + result); } catch (Exception e) { e.printStackTrace(); } return result;} 另外注意编码格式问题，在客户端用的是utf-8编码，我们在服务端仍然要用utf-8编码，否则出现中文乱码现象。
//电脑的ip地址
//手机和电脑处于同一个局域网内，所以可以通过ip访问内网Tomcat
public static String url = "