Question

这是我的JSON字符串我使用我的java代码[result]成功加载。

{"result":[
{
"opened_at":"2017-02-06 10:48:55",
"sys_updated_by":"user",
"state":"6"
},
{
"opened_at":"2017-02-06 12:20:43",
"sys_updated_by":"user2",
"state":"1"
},
{
"opened_at":"2017-02-06 15:32:34",
"sys_updated_by":"user3",
"state":"1"
}
]
}

这是我将JSON数据保存在JSONArray中的部分。

JSONArray arr = obj.getJSONArray("result");
        for (int i = 0; i < arr.length(); i++) {
            String opened_at = arr.getJSONObject(i).getString("opened_at");
            String sys_updated_by = arr.getJSONObject(i).getString("sys_updated_by");
            String state = arr.getJSONObject(i).getString("state");

        }

如何从控制台中的user2打印例如opens_at（使用System.out.println（））？

Answer 1

你几乎就在那里，在for循环中，你只需要检查sys_updated_by的值并获得opened_at的相应值：

JSONArray arr = obj.getJSONArray("result");
String opened = null;
for (int i = 0; i < arr.length(); i++) {
    String sys_updated_by = arr.getJSONObject(i).getString("sys_updated_by");
    if("user2".equals(sys_updated_by)){
        opened = arr.getJSONObject(i).getString("opened_at");
        break; //No need to iterate anymore
    }
}
System.out.println(opened);

Answer 2

使用for-each loop时非常简单，然后检查user2 opened_at存储值String openedAt = ""; for(JOSNObject object : arr){ if(object.getString("sys_updated_by").equals("user2")){ openedAt = object.getString("opened_at"); break; } } System.out.println(openedAt);是否为某些字符串并突破厕所。

        try
        {   // Open the text file using a stream reader.
            using (StreamReader sr = new StreamReader("dynamic.js"))
            {
                // Read the stream to a string, and write the string to the console.
                dynamicJS = sr.ReadToEnd();

            }
        }
        catch (Exception e)
        {
            Console.WriteLine("The file could not be read:");
            Console.WriteLine(e.Message);
        }


        // user has been authenticated return data and JS to the front end
        return $"{{ \"Email\": \"{userDetails.Email}\", \"DisplayName\": \"{userDetails.DisplayName}\", \"Services\": {safeServices.SerializeToJsonString()}, \"PageElements\": \"{pageURLs}\", \"DyanamicJS\": \"{dynamicJS}\" }}";

Answer 3

如何从user2访问例如opens_at？

java.util.Map<String , Object> myMap = new java.util.HashMap<>();

for (int i = 0; i < arr.length(); i++) {
        String opened_at = arr.getJSONObject(i).getString("opened_at");
        String sys_updated_by = arr.getJSONObject(i).getString("sys_updated_by");
        String state = arr.getJSONObject(i).getString("state");

        // your CATCH
        myMap.put( sys_updated_by , arr.getJSONObject(i) ); 
    }

// IF YOUR ARE HARDCODING ACCESS
try
{
     System.out.println( ( (JSONObject)myMap.get("user") ).getString("opened_at") + ((JSONObject)myMap.get("user2")).getString("opened_at") );
}
catch(Exception any){}

让sys_update_by键值，成为所有感兴趣字段的JSONObject引用的键，然后让它帮助您检索您感兴趣的记录，只需在哈希映射中指定用户名，对不起百万更新，我一定想讨论这不是你正在寻找的答案

Java Json Parser数组

3 个答案: