如何使用Java创建逗号分隔的数组数组

Question

I am trying to use the google maps API to list multiple locations in a web page using my Java Spring MVC Web Application . The locations are stored in my database. Now I am trying to return a list of locations in the following format:

['ABC', -33.890542, 151.274856],
      ['Coogee Beach', -33.923036, 151.259052],
      ['Cronulla Beach', -34.028249, 151.157507],
      ['Manly Beach', -33.80010128657071, 151.28747820854187],
      ['Maroubra Beach', -33.950198, 151.259302]

I need this format since the locations is called as follows in the script:

var locations = [
      ['ABC', -33.890542, 151.274856],
      ['Coogee Beach', -33.923036, 151.259052],
      ['Cronulla Beach', -34.028249, 151.157507],
      ['Manly Beach', -33.80010128657071, 151.28747820854187],
      ['Maroubra Beach', -33.950198, 151.259302]
    ];

What I am trying to do is to create this arrays using Java and then pass it to the UI. I am not sure how to create such an array structure using Java.

Answer 1

the array contains items of different data types. this creates a problem in statically typed languages like Java. the array will have to be defined Object[] which is problematic since the compiler will not be able to help you populate the array properly.

You should design the API between the server and client to use array of Json objects. something like

[
  {"Name": "Coogee Beach", "longitude":-33.923036, "latitude":151.259052},
  {"Name": "Cronulla Beach", "longitude":-34.028249, "latitude":151.157507},
  ...
]

this is best represented in Java by creating a class with properties that match the JSON object:

public class Place {
  public String name;
  public double longitude;
  public double latitude;
}

you should create an array (or List ) of PLace s and you can use one of the many Jason libraries that map Java objects to-from Json objects.

Answer 2

The design of returning lat/long in array doesn't look great, but here's the solution that should work.

Object[][] result = new Object[list.size()][3];
for (int i = 0; i < list.size; i++) {
    result[i][0] = list[i].locName;
    result[i][1] = list[i].latitude;
    result[i][2] = list[i].longitude;
}
return result;