Develop Reference

default value on <form:select /> is completely wrong - JSP

I'm passing an attribute "hours" containing the following values:
ArrayList<Integer> hours = new ArrayList<>(Arrays.asList({0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 21, 22, 23}));
model.addAttribute("hours", hours);
model.addAttribute("dto", dto);
on my jsp:
...
<form:select id="to" path="to" class="form-control chosen-select"
items="${hours}" value="${dto.to}" />
...
I have tried outputting the values on my jsp and they're all correct, the only problem is that they're completely wrong. dto.to should be an Integer "3" but it shows 13 as default selected value. What's the problem here??

Parsing comment levels from forum posts

Is it possible to find out the comment levels from this web like below?
https://www.ozbargain.com.au/node/249439#comment-3719026
From jsoup I am able to parse the comments, username etc, but I am having trouble getting the correct comment levels.
Viewing the source of that page, the doesn't match with the correct live posts, unless I am reading it all wrong.
Is there a way to solve this?
I was able to generate the source comment level using:
String url = "https://www.ozbargain.com.au/node/249439";
Document doc = Jsoup.connect(url).get();
Elements level = doc.select("ul.comment");
for(Element column : e.select("ul")){
//comment level
System.out.println(column.attr("class"));
levels.add(column.attr("class"));
}
But its doesn't look right. Only showing 1 of level 0 comment etc.
Thanks

for(Element column : e.select("ul")) {
//comment level
System.out.println(column.attr("class"));
levels.add(column.attr("class"));
}
From the above code where does the e comes from?
Anyway, you need to parse the class attribute value in order to find the comment level.
Here is a working sample code:
SAMPLE CODE
public static void main(String[] args) throws IOException {
String url="https://www.ozbargain.com.au/node/249439#comment-3719026";
Document doc = Jsoup.connect(url).get();
Elements comments = doc.select("div.comment-wrap");
Matcher levelMatcher = Pattern.compile("(?i)^(.*level)(\\d+)(.*)$").matcher("");
List<String> levels = new ArrayList<>();
System.out.println("Comments found: "+ comments.size());
for (Element comment : comments) {
if (levelMatcher.reset(comment.parent().parent().className()).find()) {
levels.add(levelMatcher.replaceAll("$2"));
}
}
System.out.println(levels);
}
OUTPUT [https://www.ozbargain.com.au/node/249439#comment-3719026] (may change depending on the request time)
Comments found: 38
[0, 1, 2, 3, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 2, 3, 3, 1, 2, 3, 3, 0, 1, 2, 3, 2, 3, 3, 2, 0, 0, 0, 1, 2, 3]
OUTPUT [https://www.ozbargain.com.au/node/249604] (may change depending on the request time)
Comments found: 14
[0, 1, 0, 1, 0, 1, 1, 2, 1, 0, 0, 1, 2, 0]

Joda DateTime deserialized from JSON as current timestamp instead of provided data

I have a JSON with Joda DateTime field. It has some sample values. But whenever I convert it to Object it automatically takes the current DateTime instead of the DateTime present in the JSON.
PFB the sample JSON
[{
"pas": "CSP",
"policyNumber": "ZU131874",
"schemeName": "PepsiCo employee scheme20",
"policyStatus": "ACTIVE",
"productCode": "GPP",
"totalSavings": 100000,
"investmentReturn": 55000,
"effectiveDate": {
"startDate": {
"dayOfYear": 2,
"year": 2014,
"dayOfMonth": 2,
"dayOfWeek": 4,
"era": 1,
"weekOfWeekyear": 1,
"millisOfSecond": 0,
"secondOfMinute": 0,
"minuteOfDay": 0,
"centuryOfEra": 20,
"yearOfCentury": 14,
"hourOfDay": 0,
"monthOfYear": 1,
"weekyear": 2014,
"minuteOfHour": 0,
"yearOfEra": 2014,
"secondOfDay": 0,
"millisOfDay": 0,
"millis": 1388601000000
},
"endDate": null
}
}, {
"pas": "CSP",
"policyNumber": "ZU146271",
"schemeName": "PepsiCo employee scheme7",
"policyStatus": "ACTIVE",
"productCode": "GPP",
"totalSavings": 100000,
"investmentReturn": 55000,
"effectiveDate": {
"startDate": {
"dayOfYear": 156,
"year": 2015,
"dayOfMonth": 5,
"dayOfWeek": 5,
"era": 1,
"weekOfWeekyear": 23,
"millisOfSecond": 0,
"secondOfMinute": 0,
"minuteOfDay": 0,
"centuryOfEra": 20,
"yearOfCentury": 15,
"hourOfDay": 0,
"monthOfYear": 6,
"weekyear": 2015,
"minuteOfHour": 0,
"yearOfEra": 2015,
"secondOfDay": 0,
"millisOfDay": 0,
"millis": 1433442600000
},
"endDate": null
}
}]
I am using following code to convert list of JSON objects to a list Of Java objects.
policies = new ArrayList<Policy>();
JsonParser parser = new JsonParser();
JsonElement jsonElement = parser.parse(new FileReader("./src/test/resources/" + "sample-zurich-pensions.json"));
Type listType = new TypeToken<List<Policy>>(){}.getType();
List<Policy> policyList = new Gson().fromJson(jsonElement, listType);
policies.addAll(policyList);
In the jsonElement I am getting the exact value, but in the policyList the DateTime is set to the current date.
PFB the classes
Policy.java
private String pas;
private String policyNumber;
private String schemeName;
private String policyStatus;
private String productCode;
private BigDecimal totalSavings;
private BigDecimal investmentReturn;
private EffectiveDate effectiveDate;
EffectiveDate.java
private DateTime startDate;
private DateTime endDate;

During deserialization from JSON, Gson is creating a new DateTime() (which is equal to current system DateTime). The fields present in your JSON are based on getters in DateTime, but there are no setters for them present, so the object cannot be adjusted to the timestamp represented by the JSON. You are much better off using a standard date-time representation like ISO 8601. Then, implement a JsonSerializer and JsonDeserializer for DateTime as suggested on the Gson site:
class DateTimeTypeConverter implements JsonSerializer<DateTime>, JsonDeserializer<DateTime> {
#Override
public JsonElement serialize(DateTime src, Type srcType, JsonSerializationContext context) {
return new JsonPrimitive(src.toString());
}
#Override
public DateTime deserialize(JsonElement json, Type type, JsonDeserializationContext context)
throws JsonParseException {
return new DateTime(json.getAsString());
}
}
or use one of the solutions provided in this post (linked also by #user2762451). You can register the serializer/deserializer like this:
GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(DateTime.class, new DateTimeTypeConverter());
Gson gson = gsonBuilder.create();

How do you turn an array into a list or how can you set up an array to be used in stickyheaders?

I have a set of data in an array and would like to turn it into a list or added the data to a list. The stickyheaders library uses lists and I need to change mine into a list since I'm having difficulty in using the stickyheaders as arrays it only shows a blank recyclerview.
This is my set of sample data, this is data is just used for creating a new event in a calendar. I retrieve the day and format it to show (e.g Monday). This is what the header will be.
If anyone can help turning this array into a list or how to add these data to a list, it would be appreciated, or if someone is familiar with stickyheaders and used arrays for it some sample code is appreciated.
public static final Event[] EventList = {
new Event("The Theory of Everything", "1:00 PM", "Cinema 1", 2015, 2, 5, 13, 0),
new Event("Kingsman the Secret Service", "3:00 PM", "Cinema 2", 2015, 2, 5, 15, 0),
new Event("Fifty Shades of Grey", "5:00 PM", "Cinema 3", 2015, 2, 5, 17, 0),
new Event("Focus", "7:00 PM", "Cinema 4", 2015, 2, 5, 19, 0),
new Event("Crazy Beautiful You", "9:00 PM", "Cinema 5", 2015, 2, 5, 21, 0),
new Event("The Theory of Everything", "1:00 PM", "Cinema 1", 2015, 2, 6, 13, 0),
new Event("Kingsman the Secret Service", "3:00 PM", "Cinema 2", 2015, 2, 6, 15, 0),
new Event("Fifty Shades of Grey", "5:00 PM", "Cinema 3", 2015, 2, 6, 17, 0),
new Event("Focus", "7:00 PM", "Cinema 4", 2015, 2, 6, 19, 0),
new Event("Crazy Beautiful You", "9:00 PM", "Cinema 5", 2015, 2, 6, 21, 0)
};

You're almost there. After that you can do:
List<Event> eventList = Arrays.asList(EventList);

How to train mahout with java?

i need to create a classifier by feature, i have 15M rows of data like:
{
"app_entertainment" : 1,
"app_widgets" : 2,
"arcade" : 8,
"books_and_reference" : 2,
"comics" : 0,
"brain" : 20,
"business" : 0,
"cards" : 5,
"casual" : 1,
"communication" : 4,
"education" : 0,
"finance" : 1,
"game_wallpaper" : 0,
"game_widgets" : 0,
"health_fitness" : 0,
"libraries_demo" : 0,
"racing" : 1,
"lifestyle" : 1,
"media_video" : 0,
"medical" : 0,
"music_and_audio" : 7,
"news_magazines" : 2,
"personalization" : 1,
"photography" : 0,
"productivity" : 4,
"shopping" : 1,
"social" : 1,
"sports_apps" : 1,
"sports_games" : 7,
"tools" : 15,
"transportation" : 2,
"travel_and_local" : 8,
"weather" : 3,
"app_wallpaper" : 0,
"entertainment" : 0,
"health_and_fitness" : 0,
"libraries_and_demo" : 0,
"media_and_video" : 0,
"news_and_magazines" : 0,
"sports" : 0
}
also for every dataset like this i know if its true or false,
the boolean is if the user with this dataset clicked on ad or not.
how can i use mahout to train a classifier and how do i classify after i trained it?
everything that i found on the net is very abstract, not many examples of how to do it via java

There are very few materials for Mahout on the internet. I referred to the Mahout source code and the source code in Mahout in Action.
You could refer to 20newsgroup source code for classification.
A simple example using NavieBayes classifier. The vector is the dataset.
public List<String> classifyCase(Vector vector) {
TreeMap<Double, String> resultMap = new TreeMap<Double, String>();
Vector result = classifier.classifyFull(vector);
for (Vector.Element element: result) {
int categoryId = element.index();
double score = element.get();
resultMap.put(-score, labels.get(categoryId));
}
return new ArrayList<String>(resultMap.values());
}