Java to JavaScript array of arrays?

Question

I've to create from Java a JSON structure like this one:

[ [ timestamp , number ],[ timestamp , number ] ]

for using it on Highcharts graphs.

I've used a "LinkedList of LinkedList" structure that I've found formatting in json in the same way, and it works.

I wished to know if there's another way to do it. A LinkedList of LinkedList sounds weird..

EDIT:

Maybe the question wasn't clear. I'm not asking how to convert the array-of-arrays in json but WHAT to convert.

In my case I know the result of the conversion and I can choose the starting structure. Other structures, instead of "LinkedList of LinkedLists" that json-ized are like this:

[ [ x, y ] , [ z, k ] , ... ]

Answer 1

If u dont want to use any collection class then by simply using following code u can make the string required to u for JSON.In following code u can keep the num variable value dynamic.

StringBuilder sb = new StringBuilder();
 sb.append("[");
 int num = 5;
 for(int i=0;i<num;i++)
 {
 sb.append("[");
 sb.append(new Date().getTime() + "," + (i+1));
 sb.append("]");
 if((i+1)<num)
 sb.append(",");
 }
 sb.append("]");

Answer 2

Another way? You haven't really said how you've already done it. I've found Json-lib easy to use and reliable, and it should turn a Java array-of-arrays into JSON for you.

• Enrichman: I know how to made the structures in JSON (I'm using the JAX-RS because I'm building a restful web service). I'm asking which should be the starting structure instead of my LinkedList-of-LinkedLists.
• Paul: Did you try an array of arrays in Java?

Answer 3

Good day!

LinkedList-of-LinkedLists is a bad way to do it, as it does not allow you to extend your structure further. You'd better take a glance at how it is implemented in existent Java-JSON wrappers. You surely need to make some class which would have encapsulated a linked list inside it. This way you could make even more complex structures without loosing readability.

Answer 4

You can use List of arrays:

List<long[]> hcData = new ArrayList<long[]>();
//add the pairs
hcData.add(new long[]{date.getTime(), number});

Just make sure your list (hcData) will be sorted according to the date, so that you don't have to play with it on the client side.