I am using Jsoup to print off HTMl to a mobile app and i know this is the code that is printing the meta data but i want to know exactly what buffer.append is doing?
StringBuffer buffer = new StringBuffer();
// Get meta info
Elements metaElems = doc.select("meta");
buffer.append("META DATA\r\n");
for (Element metaElem : metaElems) {
String name = metaElem.attr("name");
String content = metaElem.attr("content");
buffer.append("name ["+name+"] - content ["+content+"] \r\n");
}
Always somehow include the specific Class you're talking about with your code/question. To a reader, the buffer variable could be anything.
Judging from the context of your code you're probably talking about an instance of the java class StringBuffer. Read more about it here.
In a nutshell, it's like a String, just mutable, which means you can change its content after it has been instantiated like your code snippet is doing with .append(..).
Just call buffer.toString() once you're done with appending things to it and continue using the String Object that the buffer will return.
Related
OK, What I want to achieve is to write each result JSoup fetches me in a separate String. Is this somehow possible? I can get the first and last with a function but, yea, then the rest is lost.
right now i have this in my doInBackground:
// Connect to the web site
Document document = Jsoup.connect(url).get();
// Using Elements to get the Meta data
Elements titleElement = document.select("h2[property=schema:name]");
// Locate the content attribute
date1 = titleElement.toString();
Log.e("Date", String.valueOf(Html.fromHtml(date1)));
With this i get a list of results which is nice, but i'd like to have every result in a separate String.
Thanks in advance, if you need anything more please ask :)
I read through the documentation carefully again and found this:
element.eq(n).text
The "n" defines which position to get, the .text strips all the html and makes it a readable text
I write app for Android such gets data from server in JSON format. Now I get this value in string, but in my application it must look like:
Route:
1)first point
2)secon point
3).....
n) n point
I read that in Android in textView I can do it if string will be with html tags but I think it is not the best variant. After Android I must do it in iPhone now I don't know how to do that there. Send Routes as Array is not good variant too. Can you say what is the best way to decide this problem?
Have a look here you will have to find the good pattern .
Hence you have separated strings just use a list View with an ArrayAdapter.
I am not so good with regex but i think it should like : [1-9][0-9]) [[a-f][0-9]]+
I couldn't comment b/c of rep, sorry. Could you provide an example of returned JSON string. I think JSON format can be parsed with ease.
If this the case you can parse it in a loop (or another way. I'm not that good at it)
String[] parseIt (String JSON){
String[] list=JSON.split("\\d\\)");
String[] rlist=new String[list.length-1];
for(int i=0;i<list.length-1;i++){
rlist[i]=list[i+1].trim();
}
return rlist;
}
This might do trick. But you should edit result. I didn't test yet
Edit: I edited code. It simply return the address now with leading whitespace. You can get rid off them using. String trim() method like;
list[1].trim();
Do it in loop and don't care about first element (index 0).
Edit 2: Now it should work
Okay I wasn't really sure how to word this question, but basically what I want to do is, I got a url from a webView in android, and I need to put part of that url into a string, the url will look something like this: http://localhost/?code=4/3pakksajdfASDFwek.4nsKfAYN7XQVshQV0ieZDAp-PrgEcAI and I only want the part after code=, is that possible? Thanks
int start = my_string.indexOf("=");
String suffix = my_string.substring(start + 1);
If other parameters can be on the URL, or code is not always first parameter:
String url = "http://localhost/?code=4/3pakksajdfASDFwek.4nsKfAYN7XQVshQV0ieZDAp-PrgEcAI";
String code = url.replaceAll(".*(?:[?]|[&])code=([^&]+)","\1");
tests here: http://fiddle.re/nxfv
If you are totally sure the URL never has other form, you can use indexOf and substring.
Otherwise, it is better if you use URI class to extract out the query part of the URL (use getRawQuery just to be safe), then tokenize it with split along & character and find the correct key-value pair to obtain the correct value. This method is not as brittle as indexOf method above.
First, I have researched this question a lot. I learned how to read from my text file in the assets folder. The problem is that I don't want to end up with a string because the file is actually an arraylist written using json and inside that arraylist are objects. I need to access one object only. Here's what I mean:
I have a Book class, which has an int called chapter, an int called title, and an int called pageNum. I created several Book objects and added them to an ArrayList. Then I used the following code to write my ArrayList to a text file (in a regular java project):
ArrayList<Book> aList = new ArrayList<Book>();
aList.add(book1);
//etc...add more Book objects here...
File aFile = new File("books.txt");
FileOutputStream aFileStream = new FileOutputStream(aFile);
JSONOutputStream jsonOut = new JSONOutputStream(aFileStream);
jsonOut.writeObject(aList);
jsonOut.close();
That code creates a text file which I then put into the /assets folder in my Android project because I want it included with the app. In a non-Android java project I could simply use the following code to repopulate an ArrayList so that I could parse Book obects from specific indexes:
File bFile = new File("books.txt");
FileInputStream bFileStream = new FileInputStream(bFile);
JSONInputStream jsonIn = new JSONInputStream(bFileStream);
Arraylist<Book> bList = (ArrayList<Book>) jsonIn.readObject();
Book aBook = bList.get(253); //some arbitrary index
The json code I'm using comes from quickconnectfamily.org. You have to add a file called qc_json.jar to the build path of your project. http://www.quickconnectfamily.org/qcjson/more.html
The problem in Android is when I read the file using InputStream, I can only get the entire file into a string, the code above doesn't work in Android. I can't wrap JSONInputStreams around an InputStream, only around a FileInputStream. But it seems I am unable to use
FileInputStream.
So what I need is a way to create an ArrayList rather than a string in my Android app.
Without giving away too much about my app, the app basically generates a random number and creates a Book object from that index in the ArrayList. Then the user is quizzed with info from that specific book. Sounds silly, but the real app is much cooler.
I'm open to solutions, alternative methods of storing objects in a text file, etc. Please don't simply post criticism about my grammar, syntax, or application idea. I'm pretty new to app development and I couldn't care less about personal opinions. If anyone wants to see
more code I can upload it, but it doesn't seem necessary at this point. Thanks.
I figured out the solution. I connected my Evo 4G and tested the app and it worked. Here's what I did:
I used the following method to read from the file, which is what I was doing before:
InputStream is = appContext.getAssets().open("books.txt");
int size = is.available();
buffer = new byte[size];
is.read(buffer);
is.close();
String bufferString = new String(buffer);
When you do this, you end up with a String of the entire file. This is what I was able to do before, but what I wanted was a way to convert the String to an ArrayList of Book objects. Here's how I accomplished this:
//convert string to JSONArray
jsonArray = new JSONArray(bufferString);
//parse an Object from a random index in the JSONArray
JSONObject anObject = jsonArray.getJSONObject(randomNum);
Book aBook = new Book();
aBook.setTitle((String) anObject.get("title"));
//you can continue to set the different attributes of the Book object using key/value pairs from the Book class (e.g. setPageNum, setChapter, etc).
I don't know, maybe that was obvious to some people, but I really couldn't find any examples that did this. In a different question someone mentioned using the json library native to Android org.json and so I tried that and it worked.
I need to extract information from an unstructured web page in Android. The information I want is embedded in a table that doesn't have an id.
<table>
<tr><td>Description</td><td></td><td>I want this field next to the description cell</td></tr>
</table>
Should I use
Pattern Matching?
Use BufferedReader to extract the information?
Or are there faster way to get that information?
I think in this case it makes no sense to look for a fast way to extract the information as there is virtually no performance difference between the methods already suggested in answers when you compare it to the time it will take to download the HTML.
So assuming that by fastest you mean most convenient, readable and maintainable code, I suggest you use a DocumentBuilder to parse the relevant HTML and extract data using XPathExpressions:
Document doc = DocumentBuilderFactory.newInstance()
.newDocumentBuilder().parse(new InputSource(new StringReader(html)));
XPathExpression xpath = XPathFactory.newInstance()
.newXPath().compile("//td[text()=\"Description\"]/following-sibling::td[2]");
String result = (String) xpath.evaluate(doc, XPathConstants.STRING);
If you happen to retrieve invalid HTML, I recommend to isolate the relevant portion (e.g. using substring(indexOf("<table")..) and if necessary correct remaining HTML errors with String operations before parsing. If this gets too complex however (i.e. very bad HTML), just go with the hacky pattern matching approach as suggested in other answers.
Remarks
XPath is available since API Level 8 (Android 2.2). If you develop for lower API levels you can use DOM methods and conditionals to navigate to the node you want to extract
The fastest way will be parsing the specific information yourself. You seem to know the HTML structure precisely beforehand. The BufferedReader, String and StringBuilder methods should suffice. Here's a kickoff example which displays the first paragraph of your own question:
public static void main(String... args) throws Exception {
URL url = new URL("http://stackoverflow.com/questions/2971155");
BufferedReader reader = null;
StringBuilder builder = new StringBuilder();
try {
reader = new BufferedReader(new InputStreamReader(url.openStream(), "UTF-8"));
for (String line; (line = reader.readLine()) != null;) {
builder.append(line.trim());
}
} finally {
if (reader != null) try { reader.close(); } catch (IOException logOrIgnore) {}
}
String start = "<div class=\"post-text\"><p>";
String end = "</p>";
String part = builder.substring(builder.indexOf(start) + start.length());
String question = part.substring(0, part.indexOf(end));
System.out.println(question);
}
Parsing is in practically all cases definitely faster than pattern matching. Pattern matching is easier, but there is a certain risk that it may yield unexpected results, certainly when using complex regex patterns.
You can also consider to use a more flexible 3rd party HTML parser instead of writing one yourself. It will not be as fast as parsing yourself with beforehand known information. It will however be more concise and flexible. With decent HTML parsers the difference in speed is pretty negligible. I strongly recommend Jsoup for this. It supports jQuery-like CSS selectors. Extracting the firsrt paragraph of your question would then be as easy as:
public static void main(String... args) throws Exception {
Document document = Jsoup.connect("http://stackoverflow.com/questions/2971155").get();
String question = document.select("#question .post-text p").first().text();
System.out.println(question);
}
It's unclear what web page you're talking about, so I can't give a more detailed example how you could select the specific information from the specific page using Jsoup. If you still can't figure it at your own using Jsoup and CSS selectors, then feel free to post the URL in a comment and I'll suggest how to do it.
When you Scrap Html webPage. Two things you can do for it. First One is using REGEX. Another One is Html parsers.
Using Regex is not preferable by all. Because It causes logical exception at the Runtime.
Using Html Parser is More Complicated to do. you can not sure proper output will come. its too made some runtime exception by my experience.
So Better make response of the url to Xml file. and do xml parsing is very easy and effective.
Why don't you just write
int start=data.indexOf("Description");
After that take the required substring.
Why don't you create a script that does the scraping with cURL and simple html dom parser and just grab the value you need from that page? These tools work with PHP, but other tools exist for exist for any language you need.
One way of doing this is to put the html into a String and then manually search and parse through the String. If you know that the tags will come in a specific order then you should be able to crawl through it and find the data. This however is kinda sloppy, so its a question of do you want it to work now? or work well?
int position = (String)html.indexOf("<table>"); //html being the String holding the html code
String field = html.substring(html.indexOf("<td>",html.indexOf("<td>",position)) + 4, html.indexOf("</td>",html.indexOf("</td>",position)));
like i said... really sloppy. But if you're only doing this once and you need it to work, this just might do the trick.