Spring REST service: retrieving JSON from Request

Question

I am building a REST service on Spring 3.1. I am using @EnableWebMVC annotation for that. Since my service will only be accepting JSON requests, I would also like to dump the incoming request into a MongoDB collection for logging (and, later, for data transformation). I would like to access the raw JSON Request (which I could do on a non-spring implementation using "@Content HttpServletRequest request" as a method parameter). I am a Spring newbie. So, kindly help me with directions to achieve this. Thanks! UPDATE: The issue is not completely resolved. Only my tests with GET worked. It fails with POST. Therefore unchecked the accepted answer The issue is, even if I create a HttpServletRequestWrapper, I cannot forward the request after I process and wrap the request. Here is what happens: Interceptor: ``` public class DBLogInterceptor extends HandlerInterceptorAdapter { MyRequestWrapper requestWrapper; private final static Logger logger = Logger.getLogger(DBLogInterceptor.class); @Overr…

Accepted Answer

Using the HttpServletRequest object, you can get access to the URL the client used to make the request, the method used (GET, POST, PUT, etc), the query string, and headers. Getting the RequestBody may be a bit trickier and may require using the HttpServletRequestWrapper object. Since the request body can only be read once, you'll need to extend the wrapper to access it so that your target controller can still access it later to deserialize your JSON into POJO objects. ``` public class MyRequestWrapper extends HttpServletRequestWrapper { private final String body; public MyRequestWrapper(HttpServletRequest request) throws IOException { super(request); StringBuilder stringBuilder = new StringBuilder(); BufferedReader bufferedReader = null; try { InputStream inputStream = request.getInputStream(); if (inputStream != null) { bufferedReader = new BufferedReader(new InputStreamReader(inputStream)); char[] charBuffer = new char[128]; int bytesRead = -1; while ((bytesRead = bufferedReader.read(charBuffer)) > 0) { stringBuilder.append(charBuffer, 0, bytesRead); } } else { stringBuilder.append(""); } } catch (IOException ex) { throw ex; } finally { if (bufferedReader != null) { try { bufferedReader.close(); } catch (IOException ex) { throw ex; } } } body = stringBuilder.toString(); } @Override public ServletInputStream getInputStream() throws IOException { final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes()); ServletInputStream servletInputStream = new ServletInputStream() { public int read() throws IOException { return byteArrayInputStream.read(); } }; return servletInputStream; } @Override public BufferedReader getReader() throws IOException { return new BufferedReader(new InputStreamReader(this.getInputStream())); } public String getBody() { return this.body; } } ``` To access the requests in a central location, you can use either a Filter or a Spring Interceptor. Both of these are invoked prior to the request being delegated to the controller, and both have access to the servlet. Here is an actual Logging example using a Spring Interceptor: ``` package com.vaannila.interceptor; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.log4j.BasicConfigurator; import org.apache.log4j.Logger; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.handler. HandlerInterceptorAdapter; public class LoggerInterceptor extends HandlerInterceptorAdapter { static Logger logger = Logger.getLogger(LoggerInterceptor.class); static { BasicConfigurator.configure(); } @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { logger.info("Before handling the request"); return super.preHandle(request, response, handler); } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { logger.info("After handling the request"); super.postHandle(request, response, handler, modelAndView); } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { logger.info("After rendering the view"); super.afterCompletion(request, response, handler, ex); } } ``` In the LoggerInterceptor, you could use the following code to access the request: ``` MyRequestWrapper myRequestWrapper = new MyRequestWrapper((HttpServletRequest) request); String body = myRequestWrapper.getBody(); String clientIP = myRequestWrapper.getRemoteHost(); int clientPort = req…

Spring REST service: retrieving JSON from Request

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