Develop Reference

Multipart request giving issues when received in rest service

I am trying to upload a file using multipart request through angularjs and receive the content on my Rest service. I am putting up this question here after trying several helps for last 4 days and tiring myself to utmost level. I would appreciate if you can fine tune my approach or suggest another approach (I am open to any suggestions which may work as I am out of ideas now).
Just a pointer, I have tried writing a servlet to read the multipart request sent through angularjs and I got the parts correctly. But I am still putting the angular code here for your reference as I am not better on both angular and rest.
Following is the html extract for file upload:
<div>
<input type="file" data-file-upload multiple/>
<ul>
<li data-ng-repeat="file in files">{{file.name}}</li>
</ul>
</div>
Followingis the angularjs directive code extract:
.directive('fileUpload', function () {
return {
scope: true, //create a new scope
link: function (scope, el, attrs) {
el.bind('change', function (event) {
var files = event.target.files;
//iterate files since 'multiple' may be specified on the element
for (var i = 0;i<files.length;i++) {
//emit event upward
scope.$emit("fileSelected", { file: files[i] });
}
});
}
};
})
Following is the angularjs controller code extract
//a simple model to bind to and send to the server
$scope.model = {
name: "test",
comments: "TC"
};
//an array of files selected
$scope.files = [];
//listen for the file selected event
$scope.$on("fileSelected", function (event, args) {
$scope.$apply(function () {
//add the file object to the scope's files collection
$scope.files.push(args.file);
});
});
//the save method
$scope.save = function() {
$http({
method: 'POST',
url: "/services/testApp/settings/api/vsp/save",
headers: { 'Content-Type': undefined },
transformRequest: function (data) {
var formData = new FormData();
formData.append("model", angular.toJson(data.model));
for (var i = 0; i < data.files.length; i++) {
formData.append("file" , data.files[i]);
}
return formData;
},
data: { model: $scope.model, files: $scope.files }
}).
success(function (data, status, headers, config) {
alert("success!");
}).
error(function (data, status, headers, config) {
alert("failed!");
});
};
And here is my rest service code:
#Path("/vsp")
public class SampleService{
#Path("/save")
#POST
#Consumes(MediaType.MULTIPART_FORM_DATA)
public void saveProfile(#FormParam("model") String theXml,
#FormParam("file") List<File> files) throws ServletException, IOException {
final String response = "theXML: " + theXml + " and " + files.size() + " file(s) received";
System.out.println(response);
}
}
And here is the response:
theXML: {"name":"test","comments":"TC"} and 1 file(s) received
The problem is that the content of the file is coming in path and I am not able to get the input stream to read the file. I even tried using
new ByteArrayInputStream(files.get(0).getPath().getBytes())
If the content is text (like txt or csv) it works, but if the content is any other file like xls etc, the retrieved content is corrupt and unusable. Also tried using Jeresy api, but with same result. Am I missing anything obvious? Any help is appreciated.

I came across a few links, but none worked for me. So finally, I had to write a servlet to read the multipart request and added the files and the request parameters as request attributes. Once the request attributes are set, I forwarded the request to my Rest service.
Just for the record, if the multipart request is read once to extract the parts, the request will not have the parts in the forwarded servlet. So I had to set them as request attributes before forwarding.
Here is the servlet code:
public class UploadServlet extends HttpServlet {
#Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// process only if its multipart content
RequestContext reqContext = new ServletRequestContext(request);
if (ServletFileUpload.isMultipartContent(reqContext)) {
try {
List<FileItem> multiparts = new ServletFileUpload(
new DiskFileItemFactory()).parseRequest(request);
ArrayList<FileItem> fileList = new ArrayList<FileItem>();
request.setAttribute("files", fileList);
for (FileItem item : multiparts) {
if (!item.isFormField()) {
fileList.add(item);
} else {
request.setAttribute(item.getFieldName(),
item.getString());
}
}
request.setAttribute("message", "success");
} catch (Exception ex) {
request.setAttribute("message", "fail"
+ ex);
}
} else {
request.setAttribute("message",
"notMultipart");
}
System.out.println(request.getRequestURI().substring(request.getRequestURI().indexOf("upload")+6));
String forwardUri = "/api" + request.getRequestURI().substring(request.getRequestURI().indexOf("upload")+6);
request.getRequestDispatcher(forwardUri)
.forward(request, response);
}
}
Any request starting with /upload/<rest api path> will be received by the servlet and once the attributes are set, they will be forwarded to /api/<rest api path>.
In the rest api, I used the following code to retrieve the parameters.
#Path("/vsp")
public class SampleService{
#Path("/save")
#POST
#Consumes(MediaType.MULTIPART_FORM_DATA)
public void saveProfile(#Context HttpServletRequest request,
#Context HttpServletResponse response) throws Exception {
// getting the uploaded files
ArrayList<FileItem> items = (ArrayList<FileItem>)request.getAttribute("files");
FileItem item = items.get(0);
String name = new File(item.getName()).getName();
item.write( new File("C:" + File.separator + name));
// getting the data
String modelString = (String)request.getAttribute("model");
// Getting JSON from model string
JSONObject obj = JSONObject.parse(modelString);
String responseString = "model.name: " + obj.get("name") + " and " + items.size() + " file(s) received";
System.out.println(responseString);
}
}

Changing part of the html page without refreshing whole page

I have a html page and a java application with Thymeleaf templating engine and I'm looking for a tutorial to make a request to the server and render only part of the page based on response.
At this moment, I have some buttons having a link of the same page with a different parameter, my div is created based on attribute articleList (which I receive from the server based on button_id)
HTML:
button 1
button 2
<div class="" th:each="article : ${articleList}">
<p th:text="${article.getText()}">Article</p>
Java:
public class NodController implements IGTVGController {
public void process(
final HttpServletRequest request, final HttpServletResponse response,
final ServletContext servletContext, final TemplateEngine templateEngine)
throws Exception {
final WebContext ctx = new WebContext(request, response, servletContext, request.getLocale());
Integer button_id = Integer.valueOf(request.getParameter("button_id"));
List<String> articleList = getArticleList(button_id);
request.getSession().setAttribute("articleList",articleList);
templateEngine.process("/index", ctx, response.getWriter());
}
I want my buttons to process my index controller and only change the div with the articles and not refresh the entire page.
I have tried using ajax but I didn't find code examples for server-side that I could understand, so I don't know how to process the request and I don't know how to use servlets. Also I didn't manage to send any request to my current controller.
I have also found in thymeleaf api this method:
public final void process(String templateName, IContext context,
IFragmentSpec fragmentSpec, Writer writer)
where IFragmentSpec should "select a fragment of a template to be processed (once read and parsed), discarding the rest of the template" but I couldn't find more information about it as how to use it or if it is what I'm looking for.

this is the javascript code
//get text 1 by ajax
function getText1(urlstarted) {
xmlHttp = false;
if (window.XMLHttpRequest) { // Mozilla, Safari,...
xmlHttp = new XMLHttpRequest();
if (xmlHttp.overrideMimeType) {
// set type accordingly to anticipated content type
//http_request.overrideMimeType('text/xml');
xmlHttp.overrideMimeType('text/html');
}
} else if (window.ActiveXObject) { // IE
try {
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
if (!xmlHttp) {
alert('Cannot create XMLHTTP instance');
return false;
}
var url=urlstarted+"/jsp/viewText1.jsp"; //put the link to ur Ajax page here
xmlHttp.onreadystatechange = startAjaxingText;
xmlHttp.open("GET", url, true);
xmlHttp.send(null);
}
function startAjaxingText() {
if (xmlHttp.readyState != 4) {
document.getElementById('image').style.display='block' ;
document.getElementById('result').style.display='none' ;
}
if (xmlHttp.readyState == 4) {
if (xmlHttp.status == 200) {
document.getElementById('image').style.display='none' ;
document.getElementById('result').style.display='block';
document.getElementById('result').innerHTML = xmlHttp.responseText;
} else {
alert("There was a problem with the request.");
}
}
}
//get text 2 by ajax
function getText2(urlstarted) {
xmlHttp = false;
if (window.XMLHttpRequest) { // Mozilla, Safari,...
xmlHttp = new XMLHttpRequest();
if (xmlHttp.overrideMimeType) {
// set type accordingly to anticipated content type
//http_request.overrideMimeType('text/xml');
xmlHttp.overrideMimeType('text/html');
}
} else if (window.ActiveXObject) { // IE
try {
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
if (!xmlHttp) {
alert('Cannot create XMLHTTP instance');
return false;
}
var url=urlstarted+"/jsp/viewText2.jsp"; //put the link to ur Ajax page here
xmlHttp.onreadystatechange = startAjaxingText2;
xmlHttp.open("GET", url, true);
xmlHttp.send(null);
}
function startAjaxingText2() {
if (xmlHttp.readyState != 4) {
document.getElementById('image').style.display='block' ;
document.getElementById('result').style.display='none' ;
}
if (xmlHttp.readyState == 4) {
if (xmlHttp.status == 200) {
document.getElementById('image').style.display='none' ;
document.getElementById('result').style.display='block';
document.getElementById('result').innerHTML = xmlHttp.responseText;
} else {
alert("There was a problem with the request.");
}
}
}
now your buttons will look like this
<input name="button_1" id="button_1" type="button" value="button_1" onclick="getText1('<%=request.getContextPath()%>');" />
<input name="button_2" id="button_2" type="button" value="button_2"
onclick="getText2('<%=request.getContextPath()%>');" />
your div will look like
<div id="image" style="display:none"><img src="<%= request.getContextPath()%>/images/ajax-loader.gif" alt="Loading...."/> </div>
<div id="result" style="display:none"></div></td>
your viewText1.jsp page that doing ajax part
out.println("text1");//or any logic u want
your viewText2.jsp page that doing ajax part
out.println("text2");//or any logic u want
note that : the result of viewText1.jsp or viewText2.jsp must be a text either a table or paragraphs

Client-side implementation
You will have to use AJAX to load content from the server dynamically.
Consider designing your frontend as SPA. Look into AngularJS or Knockout.
Also, you can use old-school approach by using something like jQuery AJAX if this is just a small area of your application.
Separation of concerns
I strongly suggest to consider the idea to separate concerns by using server as a REST service and frontend as a client. This is the best practice for large applications if you want to keep them maintainable and scalable.
You should look for tutorials of how to implement REST with your server-side technology. It's very common practice so I think you should be able to find one.
If you have any questions I will be glad to update this answer.

How to add a cookie using doTag method in custom tag?

I have developed a custom tag library in Java which I use in my web application.
I am not sure why but my doTag() is not setting up cookie at all. I have cleared my cache and restarted my computer as well. Here is the code:
public class UserVersionOfSite extends EvenSimplerTagSupport {
private static final Log logger = LogFactory.getLog(UserVersionOfSite.class);
private StringWriter sw = new StringWriter();
#Override
public void doTag() throws IOException, JspException {
getJspBody().invoke(sw); //get the tag body and put it in StringWriter object
//get request object to get cookie value
PageContext ctx = (PageContext)getJspContext();
HttpServletRequest httpServletRequest = (HttpServletRequest) ctx.getRequest();
HttpServletResponse httpServletResponse = (HttpServletResponse) ctx.getResponse();
if(httpServletRequest.getParameterMap().containsKey("show_full_site")) {
logger.debug("show_full_site ");
if(!checkIfCookieExists(httpServletRequest)){
Cookie cookie = new Cookie("SHOW_FULL_SITE",httpServletRequest.getParameter("show_full_site"));
cookie.setMaxAge(86400);
httpServletResponse.addCookie(cookie);
//write the tag output
if(!httpServletRequest.getParameter("show_full_site").equalsIgnoreCase("true")){
//write the response
getJspContext().getOut().println(sw.toString());
}
}else{
String cookieValueString = getCookieValue(httpServletRequest.getCookies(),"SHOW_FULL_SITE","false");
if(!cookieValueString.equalsIgnoreCase("true")){
//write the response
getJspContext().getOut().println(sw.toString());
}
}
}
}
#Override
public String getResult() throws IOException {
return "User version of site";
}
public String getCookieValue(Cookie[] cookies,
String cookieName,
String defaultValue) {
for(int i=0; i<cookies.length; i++) {
Cookie cookie = cookies[i];
if (cookieName.equals(cookie.getName()))
return(cookie.getValue());
}
return(defaultValue);
}
public boolean checkIfCookieExists(HttpServletRequest httpServletRequest){
logger.debug("inside checkIfCookieExists()");
boolean cookiePresent = Arrays.asList(httpServletRequest.getCookies()).contains( "SHOW_FULL_SITE" );
return cookiePresent;
}
}
Even I tried adding the code without using if else statements but still no success. Is there any thing critical I am missing?
Any ideas guys??!!! I have checked the browser's setting as well, but there is nothing there which is blocking a creation of cookie!

I realise the horse has probably bolted by the time I'm posting this but, for the benefit of others stumbling across it, I think the problem may be related to the feature of RequestDispatcher highlighted in this question: unable to add a cookie included in JSP via jsp:include

your following line inside checkIfCookieExists() method is wrong:
Arrays.asList(httpServletRequest.getCookies()).contains( "SHOW_FULL_SITE" );
HttpServletRequest.getCookies() returns Cookie[]. You are wrapping it inside a List and checking for a string "SHOW_FULL_SITE" inside this.
Coming back to your question- how do you know cookie is not being set in the HTTP headers? Try using browser plugins like firebug to see the HTTP response headers coming from server. Also set the path of cookie before adding it to response e.g.
Cookie cookie = new Cookie("SHOW_FULL_SITE",httpServletRequest.getParameter("show_full_site"));
cookie.setMaxAge(86400);
cookie.setPath("/");

response.sendRedirect() in Servlet not working correctly after file upload

I have a web application with a simple upload function. The idea is to allow user select a file and upon successfully upload, redirect to index.jsp.
However, although the file got uploaded, the response.redirect is not working. After a successfully upload, the page doesn't get redirected. It just stays there. The weird thing is that I can see it is processing the index.jsp from the tomcat server log even though it doesn;t get redirected.
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//processRequest(request, response);
boolean status=false;
if (!ServletFileUpload.isMultipartContent(request)) {
throw new IllegalArgumentException("Request is not multipart, please 'multipart/form-data' enctype for your form.");
}
ServletFileUpload uploadHandler = new ServletFileUpload(new DiskFileItemFactory());
PrintWriter writer = response.getWriter();
response.setContentType("text/plain");
try {
List<FileItem> items = uploadHandler.parseRequest(request);
for (FileItem item : items) {
if (!item.isFormField()) {
File file = new File(getServletContext().getRealPath("/WEB-INF/upload"), item.getName());
item.write(file);
writer.write("{\"name\":\"" + item.getName() + "\",\"type\":\"" + item.getContentType() + "\",\"size\":\"" + item.getSize() + "\"}");
}
}
//redirect to index.jsp if successfully
redirect(request, response);
} catch (FileUploadException e) {
throw new RuntimeException(e);
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
writer.close();
}
}
The redirect method:
private void redirect(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.getRequestDispatcher("/index.jsp").forward(request, response);
}
The file upload plugin is from https://aquantum-demo.appspot.com/file-upload
I used the front-end and developed the upload event handler using java apache fileupload. Everything works fine except the redirect part.
The application.js file which handles the JSON returns:
$(function () {
// Initialize jQuery File Upload (Extended User Interface Version):
$('#file_upload').fileUploadUIX();
// Load existing files:
$.getJSON($('#file_upload').fileUploadUIX('option', 'url'), function (files) {
var options = $('#file_upload').fileUploadUIX('option');
options.adjustMaxNumberOfFiles(-files.length);
$.each(files, function (index, file) {
options.buildDownloadRow(file, options)
.appendTo(options.downloadTable).fadeIn();
});
});
});
Any ideas?

You're attempting to send two responses on a single request. One with JSON data in the response body and one which redirects the response to another request. This is not going to work. You can send only one response back per request. A redirect requires an untouched (uncommitted) response body, otherwise the redirect will just fail with IllegalStateException: response already committed in the server logs.
You need to move the redirect call from the servlet code to JavaScript code. Get rid of the redirect() line in the servlet and add the following line as the last line of the $.getJSON() callback function.
window.location = '/index.jsp';
This way JavaScript will take care of the redirect.

Crystal Report DB authentication in java

I'm facing a problem in Crystal Report with Eclipse.
I am using a servlet to render the crystal report viewer by writing the viewer object to the response like:
public class ReportViewer extends HttpServlet {
#SuppressWarnings("deprecation")
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
String reportName = "WEB-INF/includes/reports/"+request.getParameter("ReportName");
ReportClientDocument clientDoc = (ReportClientDocument) request.getSession().getAttribute(reportName);
if (clientDoc == null) {
// Report can be opened from the relative location specified in the CRConfig.xml, or the report location
// tag can be removed to open the reports as Java resources or using an absolute path
// (absolute path not recommended for Web applications).
clientDoc = new ReportClientDocument();
// Open report
clientDoc.open(reportName, OpenReportOptions._discardSavedData);
// Store the report document in session
ConnectionInfo info = new ConnectionInfo();
info.setUserName("sa");
info.setPassword("sa");
Tables t = clientDoc.getDatabaseController().getDatabase().getTables();
for (com.crystaldecisions.sdk.occa.report.data.ITable table : t) {
IConnectionInfo Ic = table.getConnectionInfo();
Ic.setPassword("sa");
Ic.setUserName("sa");
table.setConnectionInfo(Ic);
}
request.getSession().setAttribute(reportName, clientDoc);
}
// Create the CrystalReportViewer object
CrystalReportViewer crystalReportPageViewer = new CrystalReportViewer();
// set the reportsource property of the viewer
IReportSource reportSource = clientDoc.getReportSource();
crystalReportPageViewer.setReportSource(reportSource);
// set viewer attributes
crystalReportPageViewer.setOwnPage(true);
crystalReportPageViewer.setOwnForm(true);
// Apply the viewer preference attributes
// Process the report
crystalReportPageViewer.processHttpRequest(request, response, request.getSession(false).getServletContext(), null);
} catch (ReportSDKExceptionBase e) {
System.out.println(e);
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
When I am trying to request this servlet it redirects me to jdbc login page then it goes back to this servlet. I need to avoid jdbc login step by hardcoding it somewhere. please help me, every single comment will be appreciated.

Have you checked out the wiki over at https://wiki.sdn.sap.com/wiki/display/BOBJ/Crystal%20Reports%20Java%20%20SDK%20Samples
There are a JSP example you maybe could use:
<%# page import="com.crystaldecisions.sdk.occa.report.application.OpenReportOptions,
com.crystaldecisions.sdk.occa.report.application.ReportClientDocument,
com.crystaldecisions.sdk.occa.report.exportoptions.ReportExportFormat,
java.io.ByteArrayInputStream,
java.util.Calendar"
%><%
String reportPath;
String db_username;
String db_password;
ReportClientDocument reportClientDocument;
ByteArrayInputStream byteArrayInputStream;
byte[] byteArray;
int bytesRead;
reportPath = request.getParameter("report_path");
db_username = request.getParameter("db_username");
db_password = request.getParameter("db_password");
/*
* Instantiate ReportClientDocument and specify the Java Print Engine as the report processor.
* Open a rpt file.
*/
reportClientDocument = new ReportClientDocument();
reportClientDocument.setReportAppServer(ReportClientDocument.inprocConnectionString);
reportClientDocument.open(reportPath, OpenReportOptions._openAsReadOnly);
/*
* Set the database logon for all connections in main report.
*/
reportClientDocument.getDatabaseController().logon(db_username, db_password);
/*
* Retrieve PDF format of report and stream out to web browser.
*/
byteArrayInputStream = (ByteArrayInputStream) reportClientDocument
.getPrintOutputController().export(ReportExportFormat.PDF);
response.reset();
response.setHeader("Content-disposition", "inline;filename=crreport.pdf");
response.setContentType("application/pdf");
byteArray = new byte[1024];
while((bytesRead = byteArrayInputStream.read(byteArray)) != -1) {
response.getOutputStream().write(byteArray, 0, bytesRead);
}
response.getOutputStream().flush();
response.getOutputStream().close();
reportClientDocument.close();
%>