java - 将 Json 解析为 DBObject

Question

我有一个使用“test/plain”的 REST 服务，基本上我收到的字符串是一个 JSON 字符串，我有以下代码将 JSON 字符串解析为 DBObject，以便我可以将其保存到 MongoDB。

@Timed
@POST
@Consumes("text/plain")
@Produces(MediaType.APPLICATION_JSON)
public Response insertscreenview(String message) {
    // System.out.println(message);
    final Logger logger = LoggerFactory.getLogger(ScreenviewResource.class);
    logger.info("Screenview Insert Request Recieved" + "\n" + message);
    screenviewInstance = new Screenview();
    tracInfoInstance = new TracInfo();
    BasicDBObject ageRangeId;
    GeoCheckManager geoCheckInstance = new GeoCheckManager();
    boolean brCheck;        
    try {
        ObjectMapper mapper = new ObjectMapper();
        JsonNode actualObj = mapper.readTree(message);

        System.out.println(message);

        DBObject objInstance = (DBObject)JSON.parse(message);
 ...}

我的 JSON 字符串如下所示

{
"Screenview": {
    "TracInfo": null,
    "Id": 0,
    "ScreenName": "SettingsActivity",
    "Timestamp": "2014-07-02T18:50:10",
    "Timezone": "Asia/Kolkata",
    "ApplicationId": null,
    "DeviceId": null,
    "UserId": null,
    "SessionId": "5684ae84-9a48-49a5-ab47-fcb7de3c08cf"
},
"Session": {
    "Id": "5684ae84-9a48-49a5-ab47-fcb7de3c08cf",
    "StartTime": "2014-07-02T13:20:58",
    "EndTime": "2014-07-02T13:21:09",
    "EntryScreen": "AccessPointActivity",
    "ExitScreen": "SettingsActivity",
    "FirstEvent": "SCREEN STARTED",
    "LastEvent": "SCREEN STOPPED",
    "ApplicationId": "fa41f204bfc711e3b9f9c8cbb8c502c4",
    "DeviceId": "0_6e505bcbe7e511e393b60aba4a7caa0b",
    "UserId": "",
    "TracInfoId": -1,
    "SensorsInfo": null
},
"CustomParams": {
    "Latitude": 0,
    "Longitude": 0,
    "Country": null,
    "CountryCode": null,
    "Region": null,
    "RegionCode": null,
    "City": null,
    "Gender": null,
    "Age": 0,
    "Platform": "Android",
    "OSVersion": "16",
    "Manufacturer": "samsung",
    "Resolution": "600 * 976",
    "NetworkCarrier": null,
    "Timezone": null
} }

它给我错误如下，我无法找到原因。

java.lang.ClassCastException: java.util.HashMap cannot be cast to com.mongodb.DBObject

Answer 1

您可以使用 BasicDBObject 而不是使用 DBObject，它有一个以 Map 作为输入的构造函数:

BasicDBObject obj= new BasicDBObject(JSON.parse(message));

或使用 ObjectMapper:

BasicDBObject obj = mapper.readValue(message, BasicDBObject.class);