使用gson怎么把HashMap对象转为json格式,再从json字符串转回HashMap

1. 将HashMap对象转为json格式：

HashMap<String, String> hashMap = new HashMap<>();
hashMap.put("key1", "value1");
hashMap.put("key2", "value2");

Gson gson = new Gson();
String json = gson.toJson(hashMap);

System.out.println(json); // {"key1":"value1","key2":"value2"}

2. 将json字符串转回HashMap对象：

String json = "{\"key1\":\"value1\",\"key2\":\"value2\"}";

Type type = new TypeToken<HashMap<String, String>>(){}.getType();
HashMap<String, String> hashMap = new Gson().fromJson(json, type);

System.out.println(hashMap); // {key1=value1, key2=value2}