map的本质

Map<String, String> map = new HashMap<String, String>();
  map.put("1", "value1");
  map.put("2", "value2");
  map.put("3", "value3");

String[] array_num = ["1","2","3"];
String[] array_value= ["value1","value2","value3"];

map.get("1") == array_value[array_num.indexOf("1")];
map.get("2") == array_value[array_num.indexOf("2")];
map.get("3") == array_value[array_num.indexOf("3")];