Java – Convert Map to JSON
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Convert Map to JSON in Java
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import com.google.gson.Gson; import com.google.gson.reflect.TypeToken; import java.lang.reflect.Type; import java.util.HashMap; import java.util.Map; public class MapToJson { public static void main(String[] args) { Map<String, String> colours = new HashMap<String, String>(); colours.put("BLACK", "#000000"); colours.put("RED", "#FF0000"); colours.put("GREEN", "#008000"); colours.put("BLUE", "#0000FF"); colours.put("YELLOW", "#FFFF00"); colours.put("WHITE", "#FFFFFF"); // // Convert a Map into JSON string. // Gson gson = new Gson(); String json = gson.toJson(colours); System.out.println("json = " + json); // // Convert JSON string back to Map. // Type type = new TypeToken<Map<String, String>>() {}.getType(); Map <String, String> map = gson.fromJson(json, type); for (String key: map.keySet()) { System.out.println("map.get = " + map.get(key)); } } } |
Output:
json = {“WHITE”:”#FFFFFF”,”BLUE”:”#0000FF”,”YELLOW”:”#FFFF00″,”GREEN”:”#008000″,”BLACK”:”#000000″,”RED”:”#FF0000″}
map.get = #FFFFFF
map.get = #0000FF
map.get = #FFFF00
map.get = #008000
map.get = #000000
map.get = #FF0000
map.get = #FFFFFF
map.get = #0000FF
map.get = #FFFF00
map.get = #008000
map.get = #000000
map.get = #FF0000