Java利用Tomcat作为服务器与Android的Http通信

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 = "http://192.168.1.122:8080/MathTest/action?";











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