java - 使用 Java 有条件地访问同一级别的 JsonElements

Question

我有一个大型且复杂的 JSON 对象，如下所示:

{
    "FDN": [{
        "OT": 1,
        "CL": [{
            "K": [{
                "FID": 348,
                "VAL": "20822548"
            }, {
                "FID": "LANGUAGE_ID",
                "VAL": "FR"
            }]
        }],
        "NK": null,
        "SS": 0,
        "ITID": "NEWS",
        "TSID": 44969007,
        "DT": "20180504123302006"
    }, {
        "OT": 1,
        "CL": [{
            "K": [{
                "FID": 348,
                "VAL": "20822549"
            }, {
                "FID": "LANGUAGE_ID",
                "VAL": "AR"
            }]
        }],
        "NK": null,
        "SS": 0,
        "ITID": "NEWS",
        "TSID": 44969008,
        "DT": "20180504123302007"
    }, {
        "OT": 1,
        "CL": [{
            "K": [{
                "FID": 348,
                "VAL": "20822550"
            }, {
                "FID": "LANGUAGE_ID",
                "VAL": "FR"
            }]
        }],
        "NK": null,
        "SS": 0,
        "ITID": "NEWS",
        "TSID": 44969009,
        "DT": "20180504123302007"
    }, {
        "OT": 1,
        "CL": [{
            "K": [{
                "FID": 348,
                "VAL": "20822551"
            }, {
                "FID": "LANGUAGE_ID",
                "VAL": "AR"
            }]
        }],
        "NK": null,
        "SS": 0,
        "ITID": "NEWS",
        "TSID": 44969010,
        "DT": "20180504123302008"
    }, {
        "OT": 1,
        "CL": [{
            "K": [{
                "FID": 348,
                "VAL": "20822552"
            }, {
                "FID": "LANGUAGE_ID",
                "VAL": "FR"
            }]
        }],
        "NK": null,
        "SS": 0,
        "ITID": "NEWS",
        "TSID": 44969011,
        "DT": "20180504123302009"
    }, {
        "OT": 1,
        "CL": [{
            "K": [{
                "FID": 348,
                "VAL": "20822553"
            }, {
                "FID": "LANGUAGE_ID",
                "VAL": "FR"
            }]
        }],
        "NK": null,
        "SS": 0,
        "ITID": "NEWS",
        "TSID": 44969012,
        "DT": "20180504123302010"
    }, {
        "OT": 1,
        "CL": [{
            "K": [{
                "FID": 348,
                "VAL": "20822554"
            }, {
                "FID": "LANGUAGE_ID",
                "VAL": "FR"
            }]
        }],
        "NK": null,
        "SS": 0,
        "ITID": "NEWS",
        "TSID": 44969013,
        "DT": "20180504123302010"
    }, {
        "OT": 1,
        "CL": [{
            "K": [{
                "FID": 348,
                "VAL": "20822573"
            }, {
                "FID": "LANGUAGE_ID",
                "VAL": "AR"
            }]
        }],
        "NK": null,
        "SS": 0,
        "ITID": "NEWS",
        "TSID": 44969065,
        "DT": "20180504080929368"
    }, {
        "OT": 0,
        "CL": [{
            "K": [{
                "FID": 348,
                "VAL": "20822573"
            }, {
                "FID": "LANGUAGE_ID",
                "VAL": "AR"
            }]
        }],
        "NK": null,
        "SS": 0,
        "ITID": "NEWS",
        "TSID": 44969066,
        "DT": "20180504080929369"
    }, {
        "OT": 1,
        "CL": [{
            "K": [{
                "FID": 348,
                "VAL": "20822574"
            }, {
                "FID": "LANGUAGE_ID",
                "VAL": "AR"
            }]
        }],
        "NK": null,
        "SS": 0,
        "ITID": "NEWS",
        "TSID": 44969067,
        "DT": "20180504082130104"
    }]
}

由此，我只需要考虑这样的“CL”单元:

"CL": [{
                "K": [{
                    "FID": 348,
                    "VAL": "20822573"
                }, {
                    "FID": "LANGUAGE_ID",
                    "VAL": "AR"
                }]
            }],

检查LANGUAGE_ID是否为“AR”，然后将相应键“FID:348”的相关值(20822573)添加到列表中。只是一个前任:

 if(LANGUAGE_ID.equals("AR")){
         IdList.add("20822573");
     }

我不能这样做，因为两个键都处于同一级别。

到目前为止我的代码是:

public static void main(String[] a) throws IOException {
        FileReader jsonReader = new FileReader(new File("json.json"));
        Gson gson = new Gson();
        Map<String,String> fidMap = new HashMap<String, String>();
        JsonObject jsonObject = gson.fromJson(jsonReader, JsonObject.class);
        JsonArray fdnJsonArray = (JsonArray) jsonObject.get("FDN");

        fdnJsonArray.forEach(jsonElement -> {
            JsonArray clJsonArray = jsonElement.getAsJsonObject().get("CL").getAsJsonArray();
            clJsonArray.forEach(clJsonItem -> {
                JsonArray kJsonArray = clJsonItem.getAsJsonObject().get("K").getAsJsonArray();
                kJsonArray.forEach(kArrayElement -> {
                    String fid = kArrayElement.getAsJsonObject().get("FID").getAsString();
                    if(fid != null && !fid.isEmpty() && fid.equalsIgnoreCase("LANGUAGE_ID")) {
                        String val = kArrayElement.getAsJsonObject().get("VAL").getAsString();
                        System.out.println(fid + ":"+ val);
                    }
                });
            });
        });
    }

非常感谢您对此的帮助!

Answer 1

考虑使用jsonpath为了这。获取 CL 对象的这个特定问题的一个简单示例就像 $..CL 一样简单。然后你可以用纯java操作返回的对象。您可以在线快速制作原型(prototype) here 。要进一步细化 jsonpath 以包含语言 ID，您可以在此处查看文档:http://goessner.net/articles/JsonPath/index.html#e2