GWT RPC Testing DB connection

I'm using GWT RPC to connect to server side. On server side I've to connect to MySQL database, from which I get data I need开发者_Python百科. My question is which is best practice when I want to test my application, because I haven't deployed it yet on Tomcat app server, and it seems I cant test it, if it is not deployed. When I test it in development mode, I can't connect to database. Do I have to deploy it on Tomcat to test my application, or is there any other way.

P.S. I included JDBC driver, so that is not a problem.

You don't need to deploy to Tomcat or any other webserver to be able to test your application. Separate you test in several layers (JDBC or JPA layer, Service layer), use JUnit and Spring test and you'll be fine.

Take a look at this documentation: http://static.springsource.org/spring/docs/2.5.x/reference/testing.html

Don't really know what problems you're encountering at this time since you don't have any exceptions posted, but the best practice I follow when I test my GWT code in Development Mode is to proxy the request from GWT to a backend implementation running on a different app server. Since you're planning on moving your code to tomcat, I'm assuming you will be moving your GWT compiled code under the war directory of your J2EE project running on tomcat and the actual db calls will be done from this J2EE project. Follow the below steps.

Basically, in your GWT application, on the 'server' side, you need to create a proxy servlet that will proxy all of the requests to a different port (the port on which your backend application is running -- for example tomcat's port).

You will need to have both applications running at the same time (obviously on different ports). That way, when you're in GWT Development Mode, all of the requests are sent to the jetty app server first, and then forwarded to tomcat, and that's how you can keep on testing without copying the files back and forth and testing your real backend implementation.

The proxy Servlet (from http://edwardstx.net/wiki/attach/HttpProxyServlet/ProxyServlet.java)

package com.xxxxxxx.xxxxx.gwt.xxxxx.server;


import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.List;
import java.util.Map;
import java.util.zip.GZIPInputStream;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.httpclient.Header;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.StringRequestEntity;

/**
 * ProxyServlet from http://edwardstx.net/wiki/attach/HttpProxyServlet/ProxyServlet.java
 * (This seems to be a derivative of Noodle -- http://noodle.tigris.org/)
 * 
 * Patched to skip "Transfer-Encoding: chunked" headers, avoid double slashes
 * in proxied URLs, handle GZip and allow GWT RPC.
 */
public class ProxyServlet extends HttpServlet {

    private static final int FOUR_KB = 4196;

    /**
     * Serialization UID.
     */
    private static final long serialVersionUID = 1L;
    /**
     * Key for redirect location header.
     */
    private static final String STRING_LOCATION_HEADER = "Location";
    /**
     * Key for content type header.
     */
    private static final String STRING_CONTENT_TYPE_HEADER_NAME = "Content-Type";
    /**
     * Key for content length header.
     */
    private static final String STRING_CONTENT_LENGTH_HEADER_NAME = "Content-Length";
    /**
     * Key for host header
     */
    private static final String STRING_HOST_HEADER_NAME = "Host";
    /**
     * The directory to use to temporarily store uploaded files
     */
    private static final File FILE_UPLOAD_TEMP_DIRECTORY = new File(System.getProperty("java.io.tmpdir"));

    // Proxy host params
    /**
     * The host to which we are proxying requests. Default value is "localhost".
     */
    private String stringProxyHost = "localhost";
    /**
     * The port on the proxy host to wihch we are proxying requests. Default value is 80.
     */
    private int intProxyPort = 80;
    /**
     * The (optional) path on the proxy host to wihch we are proxying requests. Default value is "".
     */
    private String stringProxyPath = "";
    /**
     * Setting that allows removing the initial path from client. Allows specifying /twitter/* as synonym for twitter.com.
     */
    private boolean removePrefix;
    /**
     * The maximum size for uploaded files in bytes. Default value is 5MB.
     */
    private int intMaxFileUploadSize = 5 * 1024 * 1024;
    private boolean isSecure;
    private boolean followRedirects;

    /**
     * Initialize the ProxyServlet
     * @param servletConfig The Servlet configuration passed in by the servlet container
     */
    public void init(ServletConfig servletConfig) {
        // Get the proxy host
        String stringProxyHostNew = servletConfig.getInitParameter("proxyHost");
        if (stringProxyHostNew == null || stringProxyHostNew.length() == 0) {
            throw new IllegalArgumentException("Proxy host not set, please set init-param 'proxyHost' in web.xml");
        }
        this.setProxyHost(stringProxyHostNew);
        // Get the proxy port if specified
        String stringProxyPortNew = servletConfig.getInitParameter("proxyPort");
        if (stringProxyPortNew != null && stringProxyPortNew.length() > 0) {
            this.setProxyPort(Integer.parseInt(stringProxyPortNew));
        }
        // Get the proxy path if specified
        String stringProxyPathNew = servletConfig.getInitParameter("proxyPath");
        if (stringProxyPathNew != null && stringProxyPathNew.length() > 0) {
            this.setProxyPath(stringProxyPathNew);
        }
        // Get the maximum file upload size if specified
        String stringMaxFileUploadSize = servletConfig.getInitParameter("maxFileUploadSize");
        if (stringMaxFileUploadSize != null && stringMaxFileUploadSize.length() > 0) {
            this.setMaxFileUploadSize(Integer.parseInt(stringMaxFileUploadSize));
        }
    }

    /**
     * Performs an HTTP GET request
     * @param httpServletRequest The {@link HttpServletRequest} object passed
     *                            in by the servlet engine representing the
     *                            client request to be proxied
     * @param httpServletResponse The {@link HttpServletResponse} object by which
     *                             we can send a proxied response to the client
     */
    public void doGet(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)
            throws IOException, ServletException {
        // Create a GET request
        String destinationUrl = this.getProxyURL(httpServletRequest);
        debug("GET Request URL: " + httpServletRequest.getRequestURL(),
              "Destination URL: " + destinationUrl);
        GetMethod getMethodProxyRequest = new GetMethod(destinationUrl);
        // Forward the request headers
        setProxyRequestHeaders(httpServletRequest, getMethodProxyRequest);
        setProxyRequestCookies(httpServletRequest, getMethodProxyRequest);
        // Execute the proxy request
        this.executeProxyRequest(getMethodProxyRequest, httpServletRequest, httpServletResponse);
    }

    /**
     * Performs an HTTP POST request
     * @param httpServletRequest The {@link HttpServletRequest} object passed
     *                            in by the servlet engine representing the
     *                            client request to be proxied
     * @param httpServletResponse The {@link HttpServletResponse} object by which
     *                             we can send a proxied response to the client
     */
    public void doPost(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)
            throws IOException, ServletException {
        // Create a standard POST request
        String contentType = httpServletRequest.getContentType();
        String destinationUrl = this.getProxyURL(httpServletRequest);
        debug("POST Request URL: " + httpServletRequest.getRequestURL(),
              "    Content Type: " + contentType,
              " Destination URL: " + destinationUrl);
        PostMethod postMethodProxyRequest = new PostMethod(destinationUrl);
        // Forward the request headers
        setProxyRequestHeaders(httpServletRequest, postMethodProxyRequest);
        setProxyRequestCookies(httpServletRequest, postMethodProxyRequest);
        // Check if this is a mulitpart (file upload) POST

            if (contentType == null || PostMethod.FORM_URL_ENCODED_CONTENT_TYPE.equals(contentType)) {
                this.handleStandardPost(postMethodProxyRequest, httpServletRequest);
            } else {
                this.handleContentPost(postMethodProxyRequest, httpServletRequest);
            }

        // Execute the proxy request
        this.executeProxyRequest(postMethodProxyRequest, httpServletRequest, httpServletResponse);
    }



    /**
     * Sets up the given {@link PostMethod} to send the same standard POST
     * data as was sent in the given {@link HttpServletRequest}
     * @param postMethodProxyRequest The {@link PostMethod} that we are
     *                                configuring to send a standard POST request
     * @param httpServletRequest The {@link HttpServletRequest} that contains
     *                            the POST data to be sent via the {@link PostMethod}
     */
    @SuppressWarnings("unchecked")
    private void handleStandardPost(PostMethod postMethodProxyRequest, HttpServletRequest httpServletRequest) {
        // Get the client POST data as a Map
        Map mapPostParameters = (Map) httpServletRequest.getParameterMap();
        // Create a List to hold the NameValuePairs to be passed to the PostMethod
        List listNameValuePairs = new ArrayList();
        // Iterate the parameter names
        for (String stringParameterName : mapPostParameters.keySet()) {
            // Iterate the values for each parameter name
            String[] stringArrayParameterValues = mapPostParameters.get(stringParameterName);
            for (String stringParamterValue : stringArrayParameterValues) {
                // Create a NameValuePair and store in list
                NameValuePair nameValuePair = new NameValuePair(stringParameterName, stringParamterValue);
                listNameValuePairs.add(nameValuePair);
            }
        }
        // Set the proxy request POST data
        postMethodProxyRequest.setRequestBody(listNameValuePairs.toArray(new NameValuePair[]{}));
    }

    /**
     * Sets up the given {@link PostMethod} to send the same content POST
     * data (JSON, XML, etc.) as was sent in the given {@link HttpServletRequest}
     * @param postMethodProxyRequest The {@link PostMethod} that we are
     *                                configuring to send a standard POST request
     * @param httpServletRequest The {@link HttpServletRequest} that contains
     *                            the POST data to be sent via the {@link PostMethod}
     */
    private void handleContentPost(PostMethod postMethodProxyRequest, HttpServletRequest httpServletRequest) throws IOException, ServletException {
        StringBuilder content = new StringBuilder();
        BufferedReader reader = httpServletRequest.getReader();
        for (;;) {
            String line = reader.readLine();
            if (line == null) break;
            content.append(line);
        }

        String contentType = httpServletRequest.getContentType();
        String postContent = content.toString();

        if (contentType.startsWith("text/x-gwt-rpc")) {
            String clientHost = httpServletRequest.getLocalName();
            if (clientHost.equals("127.0.0.1")) {
                clientHost = "localhost";
            }

            int clientPort = httpServletRequest.getLocalPort();
            String clientUrl = clientHost + ((clientPort != 80) ? ":" + clientPort : "");
            String serverUrl = stringProxyHost + ((intProxyPort != 80) ? ":" + intProxyPort : "") + httpServletRequest.getServletPath();
            //debug("Replacing client (" + clientUrl + ") with server (" + serverUrl + ")");
            postContent = postContent.replace(clientUrl , serverUrl);
        }

        String encoding = httpServletRequest.getCharacterEncoding();
        debug("POST Content Type: " + contentType + " Encoding: " + encoding,
              "Content: " + postContent);
        StringRequestEntity entity;
        try {
            entity = new StringRequestEntity(postContent, contentType, encoding);
        } catch (UnsupportedEncodingException e) {
            throw new ServletException(e);
        }
        // Set the proxy request POST data
        postMethodProxyRequest.setRequestEntity(entity);
    }

    /**
     * Executes the {@link HttpMethod} passed in and sends the proxy response
     * back to the client via the given {@link HttpServletResponse}
     * @param httpMethodProxyRequest An object representing the proxy request to be made
     * @param httpServletResponse An object by which we can send the proxied
     *                             response back to the client
     * @throws IOException Can be thrown by the {@link HttpClient}.executeMethod
     * @throws ServletException Can be thrown to indicate that another error has occurred
     */
    private void executeProxyRequest(
            HttpMethod httpMethodProxyRequest,
            HttpServletRequest httpServletRequest,
            HttpServletResponse httpServletResponse)
            throws IOException, ServletException {
        // Create a default HttpClient
        HttpClient httpClient = new HttpClient();
        httpMethodProxyRequest.setFollowRedirects(false);
        // Execute the request
        int intProxyResponseCode = httpClient.executeMethod(httpMethodProxyRequest);
        String response = httpMethodProxyRequest.getResponseBodyAsString();

        // Check if the proxy response is a redirect
        // The following code is adapted from org.tigris.noodle.filters.CheckForRedirect
        // Hooray for open source software
        if (intProxyResponseCode >= HttpServletResponse.SC_MULTIPLE_CHOICES /* 300 */ && intProxyResponseCode  responseHeaders = Arrays.asList(headerArrayResponse);

        if (isBodyParameterGzipped(responseHeaders)) {
            debug("GZipped: true");
            if (!followRedirects && intProxyResponseCode == HttpServletResponse.SC_MOVED_TEMPORARILY) {
                response = httpMethodProxyRequest.getResponseHeader(STRING_LOCATION_HEADER).getValue();
                httpServletResponse.setStatus(HttpServletResponse.SC_OK);
                intProxyResponseCode = HttpServletResponse.SC_OK;
                httpServletResponse.setHeader(STRING_LOCATION_HEADER, response);
            } else {
                response = new String(ungzip(httpMethodProxyRequest.getResponseBody()));
            }
            httpServletResponse.setContentLength(response.length());
        }

        // Send the content to the client
        debug("Received status code: " + intProxyResponseCode,
              "Response: " + response);

        httpServletResponse.getWriter().write(response);
    }


    /**
     * The response body will be assumed to be gzipped if the GZIP header has been set.
     *
     * @param responseHeaders of response headers
     * @return true if the body is gzipped
     */
    private boolean isBodyParameterGzipped(List responseHeaders) {
        for (Header header : responseHeaders) {
            if (header.getValue().equals("gzip")) {
                return true;
            }
        }
        return false;
    }

    /**
     * A highly performant ungzip implementation. Do not refactor this without taking new timings.
     * See ElementTest in ehcache for timings
     *
     * @param gzipped the gzipped content
     * @return an ungzipped byte[]
     * @throws java.io.IOException when something bad happens
     */
    private byte[] ungzip(final byte[] gzipped) throws IOException {
        final GZIPInputStream inputStream = new GZIPInputStream(new ByteArrayInputStream(gzipped));
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(gzipped.length);
        final byte[] buffer = new byte[FOUR_KB];
        int bytesRead = 0;
        while (bytesRead != -1) {
            bytesRead = inputStream.read(buffer, 0, FOUR_KB);
            if (bytesRead != -1) {
                byteArrayOutputStream.write(buffer, 0, bytesRead);
            }
        }
        byte[] ungzipped = byteArrayOutputStream.toByteArray();
        inputStream.close();
        byteArrayOutputStream.close();
        return ungzipped;
    }

    public String getServletInfo() {
        return "GWT Proxy Servlet";
    }

    /**
     * Retrieves all of the headers from the servlet request and sets them on
     * the proxy request
     *
     * @param httpServletRequest The request object representing the client's
     *                            request to the servlet engine
     * @param httpMethodProxyRequest The request that we are about to send to
     *                                the proxy host
     */
    @SuppressWarnings("unchecked")
    private void setProxyRequestHeaders(HttpServletRequest httpServletRequest, HttpMethod httpMethodProxyRequest) {
        // Get an Enumeration of all of the header names sent by the client
        Enumeration enumerationOfHeaderNames = httpServletRequest.getHeaderNames();
        while (enumerationOfHeaderNames.hasMoreElements()) {
            String stringHeaderName = (String) enumerationOfHeaderNames.nextElement();
            if (stringHeaderName.equalsIgnoreCase(STRING_CONTENT_LENGTH_HEADER_NAME)) {
                continue;
            }
            // As per the Java Servlet API 2.5 documentation:
            //      Some headers, such as Accept-Language can be sent by clients
            //      as several headers each with a different value rather than
            //      sending the header as a comma separated list.
            // Thus, we get an Enumeration of the header values sent by the client
            Enumeration enumerationOfHeaderValues = httpServletRequest.getHeaders(stringHeaderName);
            while (enumerationOfHeaderValues.hasMoreElements()) {
                String stringHeaderValue = (String) enumerationOfHeaderValues.nextElement();
                // In case the proxy host is running multiple virtual servers,
                // rewrite the Host header to ensure that we get content from
                // the correct virtual server
                if (stringHeaderName.equalsIgnoreCase(STRING_HOST_HEADER_NAME)) {
                    stringHeaderValue = getProxyHostAndPort();
                }
                Header header = new Header(stringHeaderName, stringHeaderValue);
                // Set the same header on the proxy request
                httpMethodProxyRequest.setRequestHeader(header);
            }
        }
    }

    /**
     * Retrieves all of the cookies from the servlet request and sets them on
     * the proxy request
     *
     * @param httpServletRequest The request object representing the client's
     *                            request to the servlet engine
     * @param httpMethodProxyRequest The request that we are about to send to
     *                                the proxy host
     */
    @SuppressWarnings("unchecked")
    private void setProxyRequestCookies(HttpServletRequest httpServletRequest, HttpMethod httpMethodProxyRequest) {
        // Get an array of all of all the cookies sent by the client
        Cookie[] cookies = httpServletRequest.getCookies();
        if (cookies == null) {
            return;
        }

        for (Cookie cookie : cookies) {
            cookie.setDomain(stringProxyHost);
            cookie.setPath(httpServletRequest.getServletPath());
            httpMethodProxyRequest.setRequestHeader("Cookie", cookie.getName() + "=" + cookie.getValue() + "; Path=" + cookie.getPath());
        }
    }

    // Accessors
    private String getProxyURL(HttpServletRequest httpServletRequest) {
        // Set the protocol to HTTP
        String protocol = (isSecure) ? "https://" : "http://";
        String stringProxyURL = protocol + this.getProxyHostAndPort() + "/gui";

        // simply use whatever servlet path that was part of the request as opposed to getting a preset/configurable proxy path
        if (!removePrefix) {
            if (httpServletRequest.getServletPath() != null) {
                stringProxyURL += httpServletRequest.getServletPath();              
            }
        }
        stringProxyURL += "/";

        // Handle the path given to the servlet
        String pathInfo = httpServletRequest.getPathInfo();
        if (pathInfo != null && pathInfo.startsWith("/")) {
            if (stringProxyURL != null && stringProxyURL.endsWith("/")) {
                // avoid double '/'
                stringProxyURL += pathInfo.substring(1);
            }
        } else {
            stringProxyURL += httpServletRequest.getPathInfo();
        }
        // Handle the query string
        if (httpServletRequest.getQueryString() != null) {
            stringProxyURL += "?" + httpServletRequest.getQueryString();
        }

        stringProxyURL = stringProxyURL.replaceAll("/null", "");
        //System.out.println("----stringProxyURL: " + stringProxyURL);
        return stringProxyURL;
    }

    private String getProxyHostAndPort() {
        if (this.getProxyPort() == 80) {
            return this.getProxyHost();
        } else {
            return this.getProxyHost() + ":" + this.getProxyPort();
        }
    }

    protected String getProxyHost() {
        return this.stringProxyHost;
    }

    protected void setProxyHost(String stringProxyHostNew) {
        this.stringProxyHost = stringProxyHostNew;
    }

    protected int getProxyPort() {
        return this.intProxyPort;
    }

    protected void setSecure(boolean secure) {
        this.isSecure = secure;
    }

    protected void setFollowRedirects(boolean followRedirects) {
        this.followRedirects = followRedirects;
    }

    protected void setProxyPort(int intProxyPortNew) {
        this.intProxyPort = intProxyPortNew;
    }

    protected String getProxyPath() {
        return this.stringProxyPath;
    }

    protected void setProxyPath(String stringProxyPathNew) {
        this.stringProxyPath = stringProxyPathNew;
    }

    protected void setRemovePrefix(boolean removePrefix) {
        this.removePrefix = removePrefix;
    }

    protected int getMaxFileUploadSize() {
        return this.intMaxFileUploadSize;
    }

    protected void setMaxFileUploadSize(int intMaxFileUploadSizeNew) {
        this.intMaxFileUploadSize = intMaxFileUploadSizeNew;
    }

    private void debug(String ... msg) {
        for (String m : msg) {
            //System.out.println("[DEBUG] " + m);
        }
    }
}

You then need to subclass it and provide the port:

package xxx.xxxx.xxxxx;

import javax.servlet.ServletConfig;

public class MyProxyServlet extends ProxyServlet {
    public void init(ServletConfig servletConfig) {

        //System.out.println("in the init");
        setFollowRedirects(true);

        setRemovePrefix(false);
        //setProxyPath("gui/" + getProxyPath());
        setProxyPort(8080);

    }

}