webresourceservlet.java

esri的ArcGIS Server超级学习模板程序（for java）

package com.esri.solutions.jitk.web.util;

import java.io.IOException;
import java.io.InputStream;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.FilenameUtils; 
import org.apache.commons.io.IOUtils;

/**
 * Reads web resources (images, javascript, and stylesheets) from the
 * classpath and writes them to the Output Stream to be sent to the client.
 * This servlet looks to the PathInfo property on the request to get the resource
 * to retrieve from the classpath.  The format will be <package>/<package>.../<resource>.
 * 
 * <p>
 * This servlet only allows for certain types of web resources to be 
 * retrieved from the classpath.  The types can be configured as init-params
 * within the Web Deployment Descriptor.  The param-name is the file-extension
 * in uppercase and the param-value is the MIME type.  Example:
 * 
 * <init-param>
 * 	<param-name>JPG</param-name>
 *  <param-value>image/jpg</param-value>
 * </init-param>
 * </p>
 * 
 * <p>
 * If a request is received for a resource type that is not included in
 * the init-params then an SC_NOT_ACCEPTABLE is returned.
 * </p>
 * 
 * <p>
 * If a request is received for a resource that cannot be located, then
 * an SC_NOT_FOUND is returned.
 * </p>
 * 
 * <p>
 * If the request is not formed correctly, then an SC_BAD_REQUEST is
 * returned.
 * </p>
 *
 */
 public class WebResourceServlet extends javax.servlet.http.HttpServlet {
   
	private static final long serialVersionUID = 1L;

	/* (non-Java-doc)
	 * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	
		String resPath = null;
		String mimeType = null;
		
		resPath = request.getPathInfo();
		
		if (resPath != null) {
			InputStream in = this.getClass().getResourceAsStream(resPath);
			
			if (in == null) {
				response.sendError(HttpServletResponse.SC_NOT_FOUND);
				return;
			}
			
			String ext = FilenameUtils.getExtension(resPath);
			mimeType = this.getInitParameter(ext.toUpperCase());
			
			if (mimeType == null) {
				response.sendError(HttpServletResponse.SC_NOT_ACCEPTABLE);
				return;
			}
			
			response.setContentType(mimeType);
			IOUtils.copy(in, response.getOutputStream());
		}
		else {
			response.sendError(HttpServletResponse.SC_BAD_REQUEST);
		}
	}  	  	  	    
}