Java - String comparison

Does it give you a bellyache?

	String gg1 = "goldengate";
	String gg2 = "goldengate"; //s2 is stored in a string pool.
	String gg3 = new String("goldengate");
	System.out.println(gg1==gg2); //is true, because they share
	//the same memory addr
	System.out.println(gg1==gg3); //false, because of 'new'

view raw StringPool.java hosted with ❤ by GitHub

Never mind, you can compare them like this-

System.out.println(gg1.compareTo(gg3));

Url encode an HTTP GET Solr request and parse json using gson java library

Make a request to the SOLR webserver and parse the json string to Java classes using the code snippets below.
The JSON to be parsed-

	{
	"responseHeader": {
	"status": 0,
	"QTime": 1,
	"params": {
	"q": "searchterm1 OR searchterm2",
	"q.op": "AND",
	"wt": "json",
	"rows": "10000",
	"version": "2.2"
	}
	},
	"response": {
	"numFound": 2,
	"start": 0,
	"docs": [
	{
	"name": "searchterm1",
	"id": "1"
	},
	{
	"name": "searchterm2",
	"id": "2"
	}
	]
	}
	}

view raw Solr.json hosted with ❤ by GitHub

The corresponding Java classes-

	public class Documents {
	private String name;
	private String id;
	@Override
	public String toString() {
	return id+":"+name;
	}
	public String getName() {
	return name;
	}
	public String getID() {
	return id;
	}
	}
	public class Results {
	private String numFound;
	private ArrayList<Documents> docs;
	@Override
	public String toString() {
	return numFound +" - " + docs.toString();
	}
	public ArrayList<Documents> getDocs(){
	return docs;
	}
	public String getNumFound() {
	return numFound;
	}
	}
	public class Response {
	private Results response;
	@Override
	public String toString() {
	return response.toString();
	}
	}

view raw Classes.java hosted with ❤ by GitHub

Code snippet to make a web server call and parse using gson-

	String REQUEST_URL = "properties/select/?q=" + criteria
	+ "&q.op=AND&rows=10&version=2.2&wt=json";
	try {
	URL url = new URL(webServer + "properties/select/?q="
	+ URLEncoder.encode(criteria, "UTF-8")
	+ "&q.op=AND&rows=10&version=2.2&wt=json");
	BufferedReader in = new BufferedReader(
	new InputStreamReader(url.openStream()));
	String inputLine;
	while ((inputLine = in.readLine()) != null) {
	jsonString = inputLine;
	}
	in.close();
	//Create gson
	Gson gson = new GsonBuilder().create();
	Response r = gson.fromJson(jsonString, Response.class);
	LOG.info("MyGSON:" + r.toString());
	} catch (IOException e) {
	e.getMessage();
	e.printStackTrace();
	} catch (Exception e) {
	e.getMessage();
	e.printStackTrace();
	}

view raw ParseGson.java hosted with ❤ by GitHub

The Java classes must have the same variable names as the Json's keys. Notice how nested Json elements are handled.

Errors running builder 'Google WebApp Project Validator'

Error:

Problems occurred building the selected resources.
Errors running builder 'Java Builder' on project 'curve_app'.
com/google/gdt/eclipse/suite/preferences/GdtPreferences
Errors running builder 'Google WebApp Project Validator' on project 'curve_app'.
java.lang.NullPointerException

Workaround solution:

Close all projects, close eclipse.

Start eclipse using, "eclipse -clean" option.

You can try repeating the process 2-3 times,  if it does not work first time.

Not sure of the exact reason why this appears.

Highcharts Phantomjs Export - TypeError: 'undefined' is not an object

Generating a png file from config-

phantomjs-1.8.1/bin/phantomjs highcharts-convert.js -infile config.json  -outfile out1.png -width 300 -scale 2.5 -constr Chart -callback callback.js

Error-

	TypeError: 'undefined' is not an object (evaluating 'svgElem.getAttribute')
	phantomjs://webpage.evaluate():20
	phantomjs://webpage.evaluate():23
	phantomjs://webpage.evaluate():23
	TypeError: 'null' is not an object (evaluating 'svg.width')
	highcharts-convert.js:89
	highcharts-convert.js:322
	:/modules/webpage.js:277

view raw gistfile1.js hosted with ❤ by GitHub

Things to check-
1. The following 3 files should be there in same folder or you have to set the paths to these here-
var config = {
                /* define locations of mandatory javascript files */
                HIGHCHARTS: 'highstock.js',
                HIGHCHARTS_MORE: 'highcharts-more',
                JQUERY: 'jquery-1.8.2.min.js'
        },

2. The 'infile' parameter should have an extension of .json, because that is what it uses to decide between svg input and a configuration json.

GWT - Highchart export request - Read multipart/form-data parameters

Getting multipart-form-data request parameters in java servlet-

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
	throws IOException, ServletException {
	if (!ServletFileUpload.isMultipartContent(req)) {
	throw new ServletException("Not a file upload request");
	}
	ServletFileUpload upload = new ServletFileUpload();
	FileItemIterator iter;
	iter = upload.getItemIterator(req);
	while (iter.hasNext()) {
	FileItemStream item = iter.next();
	InputStream stream = item.openStream();
	if (item.isFormField()) {
	if (item.getFieldName().equalsIgnoreCase("svg")) {
	svg = Streams.asString(stream);
	}
	...
	...
	}
	}
	}

view raw MultipartRequestParam.java hosted with ❤ by GitHub