Question

我有一个像这样的json文件

[ {
    "id":"serve-coffee",
    "tags":[ {
        "name": "@tag1", "line": 1
    }
    ],
    "description":"Coffee should not be served\n",
    "name":"Serve coffee",
    "keyword":"Feature",
    "line":2,
    "elements":[ {
        "id": "serve-coffee;buy-last-coffee", "tags":[ {
            "name": "@tag2", "line": 6
        }
        ],
        "description":"",
        "name":"Buy last coffee",
        "keyword":"Scenario",
        "line":7,
        "steps":[ {
            "name": "there are 1 coffees left in the machine", "keyword": "Given ", "line": 8
        }
        ,
        {
            "name": "I have deposited 1$", "keyword": "And ", "line": 9
        }
        ],
        "type":"scenario"
    }
    ],
    "uri":"src\/test\/resources\/traffic-remove-locations.feature"
}

]

Iam尝试将上面的json文件转换为JSONObject。但是我遇到了类强制转换异常"java.lang.ClassCastException: org.json.simple.JSONArray cannot be cast to org.json.simple.JSONObject"

码

public static JSONObject convertFileToJSON(String fileName) throws ParseException {

        // Read from File to String
        JSONParser parser = new JSONParser();
        JSONObject jsonObject = null;
        try {
            Object object = parser.parse(new FileReader(fileName));         
            jsonObject = (JSONObject) object;   // Getting classCast Exception here.

        } catch (FileNotFoundException e) {

        } catch (IOException ioe) {

        }       
        return jsonObject;
    }

but when i changed the line jsonObject = (JSONObject) object; to JSONArray jsonArray = (JSONObject)object异常消失。但是，如果我要转换为JSONArray，那么我如何从id,tags获取description和JSONArray等值。请提供建议人

Answer 1

尝试转换为JsonArray，然后借助JSON数组中的索引逐个转换对象。

 Object object = parser.parse(new FileReader(fileName));         
 JsonArray  jsonArr = (JsonArray) object;   // Getting c
 jsonObject jsonObj = jsonArr.get(0);  //use index to access like a list

Answer 2

您的JSON文件表示一个包含一个对象的数组。因此，如果这是一个Java数据结构，那么您可以有效地执行此操作：

ID

这显然不起作用，因为你无法将数组转换为单个对象。你真正想要做的是拉出数组的第一个元素。要继续Java示例，您需要执行

# INITIAL MERGE (CROSS-PRODUCT OF ALL ID PAIRINGS)
mdf = pd.merge(df1, df2, on=['ID'])

def f(row):
    col = mdf[(mdf['ID'] == row['ID']) & 
              (mdf['date_time_x'] < row['date_time_y'])]['date_time_x'].max()
    return col

# FILTER BY MATCHED DATES TO CONDITIONAL MAX
mdf = mdf[mdf['date_time_x'] ==  mdf.apply(f, axis=1)].reset_index(drop=True)

使用JSON内容，您的int[] arr = {5}; int i = (int)arr;调用返回JSONArray，而不是JSONObject。所以你需要做这样的事情：

int[] arr = {5};
int i = (int)arr[0];

Answer 3

我也面临同样的问题。我做了以下更改以使其工作。下面是我的示例JSON。 {

"routes": [{

        "startTime": 1520319414,
        "routeInfo": [{
                "routePart": 0,
                "transType": "WALK",
                "transDetails": {
                    "startLoc": {
                        "lat": 28.6434862,
                        "lon": 77.22542659999999
                    }
                }
            }, {
                "routePart": 1,
                "transType": "BUS",
                "transDetails": {
                    "routeNumber": "307-U",
                    "interStopDetails": [{
                            "seq": 1,
                            "name": "test1",
                            "loc": {
                                "lat": 28.64302,
                                "lon": 77.2260367
                            },
                            "eta": 1520319600
                        }
                    ]
                }
            }
        ],
        "totalTime": 5742
    }
]

}

解析解决方案： JSONObject obj =（JSONObject）jsonParser.parse（new FileReader（FilepathDummy））;

        JSONArray jsonRoutes=  (JSONArray) obj.get("routes"); //Gives Main JSoN

        JSONObject  routeJsonObject = (JSONObject) jsonRoutes.get(0); // Route Array into JSON

        JSONArray routeInfoArray = (JSONArray) routeJsonObject.get("routeInfo"); //  RouteInfo Array

希望这可以解决您的问题。

类强制转换异常[JSONArray无法强制转换为org.json.simple.JSONObject]

3 个答案: