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使用JSON字符串创建哈希表

javaandroidjsonhashmap
69
在Java中从JSON字符串创建哈希映射？
我有一个JSON字符串，如{"phonetype":"N95","cat":"WP"}，想要将其转换为标准哈希映射。
我该怎么做？
1
使用 JSON 库，例如 Jackson（参见 JsonNode）。 - fge
请看这个链接.. https://dev59.com/Umkv5IYBdhLWcg3wwjgI - Vinay Veluri
处理嵌套和复杂对象：https://dev59.com/QWEh5IYBdhLWcg3wyGHy#51121461 - Natesh bhat
16个回答
78

解析 JSONObject 并创建 HashMap

public static void jsonToMap(String t) throws JSONException {

        HashMap<String, String> map = new HashMap<String, String>();
        JSONObject jObject = new JSONObject(t);
        Iterator<?> keys = jObject.keys();

        while( keys.hasNext() ){
            String key = (String)keys.next();
            String value = jObject.getString(key); 
            map.put(key, value);

        }

        System.out.println("json : "+jObject);
        System.out.println("map : "+map);
    }

测试输出：

json : {"phonetype":"N95","cat":"WP"}
map : {cat=WP, phonetype=N95}
5
请指明你正在使用哪个库，json-simple中的JSONObject没有keys()或getString()方法。 - Alexandru Severin
@VinothkumarArputharaj 当我将类似的JSON字符串转换为JSONObject时，它会被随机排序。我该如何将JSON字符串按照相同的顺序转换为JSONObject？ - KJEjava48
HashMaps不是有序的：http://docs.oracle.com/javase/6/docs/api/java/util/HashMap.html - Sarah Messer
你可以使用 Gson 库。 - chaitanya
55
您可以使用Google的Gson库将JSON转换为Hashmap。尝试以下代码
String jsonString = "Your JSON string";
HashMap<String,String> map = new Gson().fromJson(jsonString, new TypeToken<HashMap<String, String>>(){}.getType());
找了好久，谢谢。你能解释一下 TypeToken<HashMap<String, String>>(){}.getType() 吗？ - Srujan Barai
20
public class JsonMapExample {

    public static void main(String[] args) {
        String json = "{\"phonetype\":\"N95\",\"cat\":\"WP\"}";
        Map<String, String> map = new HashMap<String, String>();
        ObjectMapper mapper = new ObjectMapper();

        try {
            //convert JSON string to Map
            map = mapper.readValue(json, new TypeReference<HashMap<String, String>>() {});
            System.out.println(map);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

输出：

{phonetype=N95, cat=WP}

您可以查看这个链接，它会很有帮助：http://www.mkyong.com/java/how-to-convert-java-map-to-from-json-jackson/

org.codehaus.jackson？还在使用Jackson 1.9.x吗？;) - fge
7

你可以使用Gson库

Type type = new TypeToken<HashMap<String, String>>() {}.getType();
new Gson().fromJson(jsonString, type);
5

这是一个简单的操作，不需要使用任何外部库。

相反，您可以使用这个类：（处理甚至包含列表、嵌套列表和 JSON 的情况）

public class Utility {

    public static Map<String, Object> jsonToMap(Object json) throws JSONException {

        if(json instanceof JSONObject)
            return _jsonToMap_((JSONObject)json) ;

        else if (json instanceof String)
        {
            JSONObject jsonObject = new JSONObject((String)json) ;
            return _jsonToMap_(jsonObject) ;
        }
        return null ;
    }


   private static Map<String, Object> _jsonToMap_(JSONObject json) throws JSONException {
        Map<String, Object> retMap = new HashMap<String, Object>();

        if(json != JSONObject.NULL) {
            retMap = toMap(json);
        }
        return retMap;
    }


    private static Map<String, Object> toMap(JSONObject object) throws JSONException {
        Map<String, Object> map = new HashMap<String, Object>();

        Iterator<String> keysItr = object.keys();
        while(keysItr.hasNext()) {
            String key = keysItr.next();
            Object value = object.get(key);

            if(value instanceof JSONArray) {
                value = toList((JSONArray) value);
            }

            else if(value instanceof JSONObject) {
                value = toMap((JSONObject) value);
            }
            map.put(key, value);
        }
        return map;
    }


    public static List<Object> toList(JSONArray array) throws JSONException {
        List<Object> list = new ArrayList<Object>();
        for(int i = 0; i < array.length(); i++) {
            Object value = array.get(i);
            if(value instanceof JSONArray) {
                value = toList((JSONArray) value);
            }

            else if(value instanceof JSONObject) {
                value = toMap((JSONObject) value);
            }
            list.add(value);
        }
        return list;
    }
}

要将您的JSON字符串转换为哈希映射，请使用以下方法：

使用此代码：

HashMap<String, Object> hashMap = new HashMap<>(Utility.jsonToMap(response)) ;
1
这比被接受的答案好多了，因为它处理嵌套和复杂对象。对我帮助很大 :) - user2810114
2
在Java中，我们可以使用以下语句来实现。我们需要使用Jackson ObjectMapper，并将HashMap.class作为映射类提供。最后将结果存储为HashMap对象。
HashMap<String,String> hashMap = new ObjectMapper().readValue(jsonString, HashMap.class);
2
HashMap<String, String> hashMap = new HashMap<String, String>();
String string = "{\"phonetype\":\"N95\",\"cat\":\"WP\"}";

try {
    JSONObject json = new JSONObject(string);

    hashMap.put("phonetype", json.getString("phonetype"));
    hashMap.put("cat", json.getString("cat"));
} catch (JSONException e) {
     // TODO Handle expection!
}
4
请勿使用空的 catch 块。 - peter.petrov
此解决方案仅适用于 {"phonetype":"N95","cat":"WP"}，它应该是通用的。 - Paramesh Korrakuti
3
这里不关注捕获块，所以我同意 - 将它们保持为空以便集中注意力于实际逻辑。 - NullPumpkinException
2
HashMap<String, Object> map = new Gson().fromJson(jsonString, HashMap.class);

试试这个

0

考虑这个 JSON 字符串

{
    "12": [
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/12/12_960x540_200k.mp4/manifest.mpd",
            "video_bitrate": "200k",
            "audio_bitrate": "32k",
            "video_width": 960,
            "video_height": 540,
            "file_size": 125465600
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/12/12_960x540_80k.mp4/manifest.mpd",
            "video_bitrate": "80k",
            "audio_bitrate": "32k",
            "video_width": 960,
            "video_height": 540,
            "file_size": 50186240
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/12/12_640x360_201k.mp4/manifest.mpd",
            "video_bitrate": "201k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 145934731
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/12/12_640x360_199k.mp4/manifest.mpd",
            "video_bitrate": "199k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 145800030
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/12/12_640x360_79k.mp4/manifest.mpd",
            "video_bitrate": "79k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 71709477
        }
    ],
    "13": [
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/13/13_960x540_200k.mp4/manifest.mpd",
            "video_bitrate": "200k",
            "audio_bitrate": "32k",
            "video_width": 960,
            "video_height": 540,
            "file_size": 172902400
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/13/13_960x540_80k.mp4/manifest.mpd",
            "video_bitrate": "80k",
            "audio_bitrate": "32k",
            "video_width": 960,
            "video_height": 540,
            "file_size": 69160960
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/13/13_640x360_201k.mp4/manifest.mpd",
            "video_bitrate": "201k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 199932081
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/13/13_640x360_199k.mp4/manifest.mpd",
            "video_bitrate": "199k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 199630781
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/13/13_640x360_79k.mp4/manifest.mpd",
            "video_bitrate": "79k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 98303415
        }
    ],
    "14": [
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/14/14_960x540_200k.mp4/manifest.mpd",
            "video_bitrate": "200k",
            "audio_bitrate": "32k",
            "video_width": 960,
            "video_height": 540,
            "file_size": 205747200
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/14/14_960x540_80k.mp4/manifest.mpd",
            "video_bitrate": "80k",
            "audio_bitrate": "32k",
            "video_width": 960,
            "video_height": 540,
            "file_size": 82298880
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/14/14_640x360_201k.mp4/manifest.mpd",
            "video_bitrate": "201k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 237769546
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/14/14_640x360_199k.mp4/manifest.mpd",
            "video_bitrate": "199k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 237395552
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/14/14_640x360_79k.mp4/manifest.mpd",
            "video_bitrate": "79k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 116885686
        }
    ],
    "15": [
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/15/15_960x540_200k.mp4/manifest.mpd",
            "video_bitrate": "200k",
            "audio_bitrate": "32k",
            "video_width": 960,
            "video_height": 540,
            "file_size": 176128000
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/15/15_960x540_80k.mp4/manifest.mpd",
            "video_bitrate": "80k",
            "audio_bitrate": "32k",
            "video_width": 960,
            "video_height": 540,
            "file_size": 70451200
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/15/15_640x360_201k.mp4/manifest.mpd",
            "video_bitrate": "201k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 204263286
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/15/15_640x360_199k.mp4/manifest.mpd",
            "video_bitrate": "199k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 204144447
        },
        {
            "dash_url": "http://mediaserver.superprofs.com:1935/vods3/_definst_/mp4:amazons3/superprofs-media/private/lectures/15/15_640x360_79k.mp4/manifest.mpd",
            "video_bitrate": "79k",
            "audio_bitrate": "32k",
            "video_width": 640,
            "video_height": 360,
            "file_size": 100454382
        }
    ]
}

使用Jackson解析器
 private static ObjectMapper underScoreToCamelCaseMapper;

    static {
        final DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

        underScoreToCamelCaseMapper = new ObjectMapper();
        underScoreToCamelCaseMapper.setDateFormat(df);
        underScoreToCamelCaseMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        underScoreToCamelCaseMapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);
        underScoreToCamelCaseMapper.setPropertyNamingStrategy(
                PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES);
}
    public static <T> T parseUnderScoredResponse(String json, Class<T> classOfT) {
        try {
            if (json == null) {
                return null;
            }
            return underScoreToCamelCaseMapper.readValue(json, classOfT);

        } catch (JsonParseException e) {
        } catch (JsonMappingException e) {
        } catch (IOException e) {
        }
        return null;
    }

使用以下代码进行解析
 HashMap<String, ArrayList<Video>> integerArrayListHashMap =
                JsonHandler.parseUnderScoredResponse(test, MyHashMap.class);

其中 MyHashMap 是

 private static class MyHashMap extends HashMap<String,ArrayList<Video>>{
    }
0

没有JSON库，只有String和HashMap。
保持简单！
希望适用于所有人。

// 基于String的JSON转换为HashMap示例

    String tempJson = "{\"incomePhone\":\"213121122\",\"clientId\":\"1001\",\"clientAccountManager\":\"Gestor de Conta 1\",\"clientRetailBranch\":\"100\",\"phoneAccountManager\":\"7800100\"}";
    System.out.println(tempJson);

    String[] parts = tempJson.split(",");
    HashMap<String,String> jsonHash = new HashMap<String,String>();

    for(int i=0;i<parts.length;i++){
        parts[i]    =   parts[i].replace("\"", "");
        parts[i]    =   parts[i].replace("{", "");
        parts[i]    =   parts[i].replace("}", "");
        String[] subparts = parts[i].split(":");
        jsonHash.put(subparts[0],subparts[1]);
    }
这将无法处理任何数组和可能的嵌套对象。 - Christopher Schneider
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