java - 如何使用 GSON 获取 JSON 数据

Question

这可能以前有人问过，但我不知道我的问题的术语，因此不知道要查找什么。

我正在使用 GSON 和 Java 尝试从已解析的 JSONElement 中获取信息。

Java代码:

    JsonParser parser = new JsonParser();

    String url = "https://chapel-logs.herokuapp.com/attendance";

    URL obj = new URL(url);
    HttpURLConnection con = (HttpURLConnection) obj.openConnection();

    // optional default is GET
    con.setRequestMethod("GET");

    //add request header
    con.setRequestProperty("Accept", "application/json");

    int responseCode = con.getResponseCode();
    System.out.println("\nSending 'GET' request to URL : " + url);
    System.out.println("Response Code : " + responseCode);

    BufferedReader in = new BufferedReader(
            new InputStreamReader(con.getInputStream()));
    String inputLine;
    StringBuffer response = new StringBuffer();

    while ((inputLine = in.readLine()) != null) {
        response.append(inputLine);
    }

    in.close();

    //print result
    JsonElement element = parser.parse(response.toString());

    if (element.isJsonObject()) {
        JsonObject albums = element.getAsJsonObject();
        System.out.println(albums.get("students")); //prints out data in students
        System.out.println(albums.get("students.LastChapelAttended")); //error
    }

我的 JSON:

{"students":[{"LastChapelAttended":{"Loc":"","Chapel":"WhyChapel","Year":2018,"Month":9,"Day":6,"Hour":15,"Min":14,"Sec":28},"StudNum":"F02660934","Attendance":17},{"LastChapelAttended":{"Loc":"","Chapel":"WhyChapel","Year":2018,"Month":9,"Day":5,"Hour":19,"Min":49,"Sec":11},"StudNum":"002660934","Attendance":2},{"LastChapelAttended":{"Loc":"","Chapel":"WhyChapel","Year":2018,"Month":9,"Day":4,"Hour":20,"Min":35,"Sec":57},"StudNum":"002643472","Attendance":2},{"LastChapelAttended":{"Loc":"","Chapel":"WhyChapel","Year":2018,"Month":9,"Day":7,"Hour":5,"Min":34,"Sec":54},"StudNum":"002664906","Attendance":1}]}

我要获取的数据是:LastChapelAttended，但是 LastChapelAttended 在 students 中。在 JavaScript 中，如果有帮助，与我正在尝试的等效的是 students.LastChapelAttended。

提前致谢!

Answer 1

JsonObject jObj=(JsonObject)albums.get("students").getAsJsonArray().get(0);
System.out.println(jObj.get("LastChapelAttended"));

将其作为 JsonArray 获取，然后遍历数组以获取 LastChapelAttended。