使用HttpURLConnection访问接口进行数据处理

项目中有这样一个场景：web工程接收到外部数据后，需要转发给biz工程进行处理，然后biz将处理结果数据返回给web工程。为什么要这么做呢？是因为蛋疼的网络权限控制，只有web工程能够跟外部打交道，那么问题来了，这种交互模式如何处理？

这里就使用到了HttpURLConnection对象，直接看如下方法吧，在web工程中使用如下：

public static String getResponseMessage(String resMsgUrl, String requestXmlData) throws IOException

{

// 向biz的接口发用户的上行消息，把requestXmlData发给biz工程的接口，这里的resMsgUrl就是biz工程提供的url

URL url = new URL(resMsgUrl);

//建立连接

HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();

//设置是否向HttpURLConnection输出，因为这个是post请求，参数放在http正文内，因此需要设置为true，默认为false

httpURLConnection.setDoOutput(true);

//设置是否从HttpURLConnection读入，默认为true

httpURLConnection.setDoInput(true);

//设置请求方法

httpURLConnection.setRequestMethod("POST");

//设置连接超时时间

httpURLConnection.setConnectTimeout(5000);

//设置读取超时时间

httpURLConnection.setReadTimeout(5000);

//对请求的正文使用urlencode进行编码

httpURLConnection.setRequestProperty("content-type", "application/x-www-form-urlencoded");

//一定是上面的参数设置完了之后才进行connection连接

httpURLConnection.connect();

//使用BufferedWriter对象进行参数写入到正文

BufferedWriter out = new BufferedWriter(new OutputStreamWriter(httpURLConnection.getOutputStream(), "UTF-8"));

if(StringUtils.isNotEmpty(requestXmlData)){

out.write(requestXmlData);

}

out.flush();

out.close();

int code = httpURLConnection.getResponseCode();

String message = httpURLConnection.getResponseMessage();

logger.info("%%%name:" + httpURLConnection.getHeaderField("name"));

// 连接成功后，从biz的接口读取返回的message

if (code == 200 || message.equalsIgnoreCase("ok"))

{

InputStream inputStream = httpURLConnection.getInputStream();

String resonpseMessage = readBytesFromStream(inputStream);

inputStream.close();

httpURLConnection.disconnect();

return resonpseMessage;

}

httpURLConnection.disconnect();

return "";

}

biz提供接口，先从request对象中读出web的请求参数，然后根据参数在数据库中找到欲返回的信息，然后通过BufferedWriter对象写入到response中，代码如下：

@RequestMapping(value="res_message.xhtml",method = RequestMethod.POST)

public void resMessage(HttpServletRequest request, HttpServletResponse response) throws IOException{

String requestXmlData = Util.getRequestXmlData(request);

String resopnseXmlData = messageService.getResponseXml(requestXmlData);

response.setCharacterEncoding("UTF-8");

logger.info("&&&&&&&resopnseXmlData:"+resopnseXmlData);

BufferedWriter out = new BufferedWriter(new OutputStreamWriter(response.getOutputStream(), "UTF-8"));

out.write(resopnseXmlData);

out.flush();

out.close();

}

二者的交互就完成了，值得注意的是，上述两个方法中都涉及到了从request或InputStream中读取数据，这里有两种模式：

1、按行读取，例如：

public static String getRequestXmlData(HttpServletRequest request) throws IOException

{

request.setCharacterEncoding("UTF-8");

BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream) request.getInputStream(), "UTF-8"));

String line;

StringBuilder sb = new StringBuilder();

while ((line = br.readLine()) != null)

{

sb.append(line);

}

String recievestr = sb.toString();

return recievestr;

}

public static String readBytesFromStream(InputStream inputStream) throws IOException

{

String responseStr = "";

String totalResponseStr = "";

BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));

while ((responseStr = reader.readLine()) != null)

{

totalResponseStr += responseStr + "\n";

}

return totalResponseStr;

}

2、按规定字符串长度读取

逐字节读取：

public static String getRequestXmlData(HttpServletRequest request) throws IOException {

ServletInputStream sis = request.getInputStream();

int size = request.getContentLength()==-1?0:request.getContentLength();

byte[] buffer = new byte[size];

byte[] xmldataByte = new byte[size];

int count = 0;

int rbyte = 0;

while (count < size) {

rbyte = sis.read(buffer);

for (int i = 0; i < rbyte; i++) {

xmldataByte[count + i] = buffer[i];

}

count += rbyte;

}

return new String(xmldataByte, "UTF-8");

}

这里很容易出现乱码，因为每次按长度进行读取，如果刚好一个汉字被截断，就会出现乱码，因此不建议这么使用。

public static String readBytesFromInputStream(InputStream inputStream) throws IOException

{

byte[] b = new byte[1024];

String res = "";

int bytesRead = 0;

while (true) {

bytesRead = inputStream.read(b, 0, 1024);

if (bytesRead == -1) {

return res;

}

res += new String(b, 0, bytesRead, "UTF-8");

}

}