mapcomppreviewservlet.java

esri的ArcGIS Server超级学习模板程序（for java）

package com.esri.solutions.jitk.web.tasks.mapcomp;

import java.io.File;
import java.io.IOException;
import java.text.MessageFormat;
import java.util.UUID;

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

import org.apache.commons.codec.binary.Base64;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import com.esri.solutions.jitk.common.personalization.ConstantUserId;
import com.esri.solutions.jitk.personalization.PersonalizationException;
import com.esri.solutions.jitk.personalization.data.IMapComposition;
import com.esri.solutions.jitk.personalization.data.IPersonalizationData;
import com.esri.solutions.jitk.personalization.data.IPersonalizationDataFactory;
import com.esri.solutions.jitk.personalization.data.beans.v1.MapCompositionType;
import com.esri.solutions.jitk.personalization.data.beans.v1.PreviewType;

/**
 * Generates the Preview for a specified Map Composition.  This servlet needs
 * to be configured with path-style URL mappings and not extension-style mappings.  This
 * servlet expects the URL to be configured like the following:
 * 
 * <code>http://host/Viewer/maps/preview/<username>/<id> where
 * 
 * <ul>
 * 	<li>username is the name of the user that created the Map Composition
 *  <li>id is the unique identifier for the Map Composition
 * </ul>
 * 
 * In this example, this servlet would need to be mapped to /maps/preview/* URL patterns.
 * 
 * <p>
 * This servlet will send a 404 (Not Found) response if any of the conditions are met:
 * 	<ul>
 * 		<li>{@link HttpServletRequest#getPathInfo()} is null or zero-length.
 * 		<li>Personalization Data cannot be retrieved for the user.
 * 		<li>Map Composition with the specified ID cannot be found.
 *  	<li>ID is not in the correct format.
 *  	<li>Preview cannot be found for the Map Composition
 *  	<li>Any unexpected exceptions occur.
 * 	</ul>
 * </p>
 */
 public class MapCompPreviewServlet extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
	 
	private static final String ERROR_INCORRECT_PATH_INFO = "Incorrect Path Information in Request.";
	private static final String ERROR_ID_IN_BAD_FORMAT = "ID [{0}] is not in acceptable format";
	private static final String ERROR_PERS_EXCEPTION = "Cannot retrieve Map Composition Preview [{0}]";
	private static final String ERROR_NO_PREVIEW_IN_MAP_COMP = "Map Composition [{0}] does not contain a Preview.";
	private static final String ERROR_MAP_COMP_NOT_FOUND = "Map Composition [{0}] not found.";
	private static final String ERROR_PERS_DATA_NOT_FOUND = "Unable to create Personalization Data object.";
	private static final long serialVersionUID = 1986336733811201885L;
	private static final Logger LOG = LogManager.getLogger(MapCompPreviewServlet.class);
	
	/* (non-Java-doc)
	 * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		IPersonalizationDataFactory factory = null;
		IPersonalizationData data = null;
		IMapComposition mc = null;
		MapCompositionType bean = null;
		ConstantUserId userId = null;
		
		String pathInfo = request.getPathInfo();
		if (pathInfo == null || pathInfo.trim().length() == 0) {
			LOG.error(ERROR_INCORRECT_PATH_INFO);
			log(ERROR_INCORRECT_PATH_INFO);
			response.sendError(HttpServletResponse.SC_NOT_FOUND);
			return;
		}
		
		File resource = new File(pathInfo);
		String username = resource.getParent().replace(File.separator, "");
		String id = resource.getName();
		
		userId = new ConstantUserId();
		userId.setUsername(username);
		
		WebApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
		factory = (IPersonalizationDataFactory) ctx.getBean("dbPersonalizationDataFactory");
		
		try {
			data = factory.create(userId);
		} catch (PersonalizationException e) {
			LOG.error(ERROR_PERS_DATA_NOT_FOUND);
			log(ERROR_PERS_DATA_NOT_FOUND);
			response.sendError(HttpServletResponse.SC_NOT_FOUND);
			return;
		}
		
		try {
			UUID mcId = UUID.fromString(id);
			mc = data.getMapComposition(mcId);
			
			if (mc == null) {
				LOG.error(MessageFormat.format(ERROR_MAP_COMP_NOT_FOUND, id));
				log(MessageFormat.format(ERROR_MAP_COMP_NOT_FOUND, id));
				response.sendError(HttpServletResponse.SC_NOT_FOUND);
				return;
			}
			
			bean = mc.getMapComposition();
			PreviewType preview = bean.getPreview();
			if (preview != null) {
				byte[] preview64Data = preview.getValue();
				byte[] imageData = Base64.decodeBase64(preview64Data);
				
				response.setContentType(preview.getType());
				ServletOutputStream out = response.getOutputStream();
				out.write(imageData);
			} else {
				LOG.error(MessageFormat.format(ERROR_NO_PREVIEW_IN_MAP_COMP, id));
				log(MessageFormat.format(ERROR_NO_PREVIEW_IN_MAP_COMP, id));
				response.sendError(HttpServletResponse.SC_NOT_FOUND);
				return;
			}
			
		} catch (PersonalizationException e) {
			LOG.error(MessageFormat.format(ERROR_PERS_EXCEPTION, id));
			log(MessageFormat.format(ERROR_PERS_EXCEPTION, id));
			response.sendError(HttpServletResponse.SC_NOT_FOUND);
			return;
		} catch (IllegalArgumentException e) {
			LOG.error(MessageFormat.format(ERROR_ID_IN_BAD_FORMAT, id));
			log(MessageFormat.format(ERROR_ID_IN_BAD_FORMAT, id));
			response.sendError(HttpServletResponse.SC_NOT_FOUND);
			return;
		} catch (NullPointerException npe) {
			LOG.error(MessageFormat.format(ERROR_MAP_COMP_NOT_FOUND, id));
			log(MessageFormat.format(ERROR_MAP_COMP_NOT_FOUND, id));
			response.sendError(HttpServletResponse.SC_NOT_FOUND);
			return;			
		}
	}  	  	  	    
}