通过map获取json指定字段

{
    "func":"staffExportInvigilationPhoto",
    "bandTestExamUserId": 311,
    "photoType": 1,
    "token": "74_rXsFyYMeiNjJOQAYdAJMFrCclEZGobpkXJTLLzWGsxC2GWSUfR1kJZuhvZBLq2afg6q38GxI="
}

ObjectMapper mapper = new ObjectMapper();
 
Map parameterMap = mapper.readValue(inputJsonString, Map.class);

 最后通过map.getKey()即可得到