creating Hashmap from a JSON String

Question

creating a hashmap from a json string in java   I have json string like   phonetype   N95   cat   WP   and want to convert into a standard Hashmap   How can i do it

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No JSON libraries  just String and HashMap   Keeps it simple   Hope it suits to all       JSON Transform to HashMap example based on String      String tempJson       incomePhone     213121122     clientId     1001     clientAccountManager     Gestor de Conta 1     clientRetailBranch     100     phoneAccountManager     7800100          System out println tempJson        String   parts   tempJson split           HashMap lt String String gt  jsonHash   new HashMap lt String String gt          for int i 0 i lt 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

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You could use Jackson to do this  I have yet to find a simple Gson solution   Where data map json is a JSON  object  resource file and data list json is a JSON  array  resource file   import java io File  import java io IOException  import java net MalformedURLException  import java net URISyntaxException  import java net URL  import java util List  import java util Map  import java util Scanner   import com fasterxml jackson core JsonGenerationException  import com fasterxml jackson core JsonParseException  import com fasterxml jackson core JsonProcessingException  import com fasterxml jackson core type TypeReference  import com fasterxml jackson databind JsonMappingException  import com fasterxml jackson databind ObjectMapper          Based on         http   www mkyong com java how-to-convert-java-map-to-from-json-jackson      public class JsonLoader       private static final ObjectMapper OBJ MAPPER      private static final TypeReference lt Map lt String Object gt  gt  OBJ MAP      private static final TypeReference lt List lt Map lt String Object gt  gt  gt  OBJ LIST       static           OBJ MAPPER   new ObjectMapper            OBJ MAP   new TypeReference lt Map lt String Object gt  gt               OBJ LIST   new TypeReference lt List lt Map lt String Object gt  gt  gt                  public static void main String   args            try               System out println jsonToString parseJsonString read  data map json   true                  System out println jsonToString parseJsonString read  data array json   true                catch  IOException e                e printStackTrace                         private static final Object parseJsonString String jsonString            try               if  jsonString startsWith                         return readJsonObject jsonString                 else if  jsonString startsWith                         return readJsonArray jsonString                           catch  JsonGenerationException e                e printStackTrace              catch  JsonMappingException e                e printStackTrace              catch  IOException e                e printStackTrace                       return null             public static String jsonToString Object json  throws JsonProcessingException           return OBJ MAPPER writerWithDefaultPrettyPrinter   writeValueAsString json              private static final Map lt String Object gt  readJsonObject String jsonObjectString  throws JsonParseException  JsonMappingException  IOException           return OBJ MAPPER readValue jsonObjectString  OBJ MAP              private static final List lt Map lt String Object gt  gt  readJsonArray String jsonArrayString  throws JsonParseException  JsonMappingException  IOException           return OBJ MAPPER readValue jsonArrayString  OBJ LIST              public static final Map lt String Object gt  loadJsonObject String path  boolean isResource  throws JsonParseException  JsonMappingException  MalformedURLException  IOException           return OBJ MAPPER readValue load path  isResource   OBJ MAP              public static final List lt Map lt String Object gt  gt  loadJsonArray String path  boolean isResource  throws JsonParseException  JsonMappingException  MalformedURLException  IOException           return OBJ MAPPER readValue load path  isResource   OBJ LIST              private static final URL pathToUrl String path  boolean isResource  throws MalformedURLException           if  isResource                return JsonLoader class getClassLoader   getResource path                      return new URL  file      path              protected static File load String path  boolean isResource  throws MalformedURLException           return load pathToUrl path  isResource               protected static File load URL url            try               return new File url toURI               catch  URISyntaxException e                return new File url getPath                          public static String read String path  boolean isResource  throws IOException           return read path   UTF-8   isResource              public static String read String path  String charset  boolean isResource  throws IOException           return read pathToUrl path  isResource   charset               SuppressWarnings  resource       public static String read URL url  String charset  throws IOException           return new Scanner url openStream    charset  useDelimiter    A   next                Extra  Here is the complete code for Dheeraj Sachan s example   import java io File  import java io IOException  import java io Serializable  import java net MalformedURLException  import java net URISyntaxException  import java net URL  import java text DateFormat  import java text SimpleDateFormat  import java util HashMap  import java util Iterator  import java util List  import java util Map Entry  import java util Scanner   import com fasterxml jackson annotation JsonAutoDetect  import com fasterxml jackson annotation PropertyAccessor  import com fasterxml jackson core JsonParseException  import com fasterxml jackson databind DeserializationFeature  import com fasterxml jackson databind JsonMappingException  import com fasterxml jackson databind ObjectMapper  import com fasterxml jackson databind PropertyNamingStrategy   public class JsonHandler       private static ObjectMapper propertyMapper       static           final DateFormat df   new SimpleDateFormat  yyyy-MM-dd HH mm ss             propertyMapper   new ObjectMapper            propertyMapper setDateFormat df           propertyMapper configure DeserializationFeature FAIL ON UNKNOWN PROPERTIES  false           propertyMapper setVisibility PropertyAccessor FIELD  JsonAutoDetect Visibility ANY           propertyMapper setPropertyNamingStrategy PropertyNamingStrategy CAMEL CASE TO LOWER CASE WITH UNDERSCORES              private static class MyHashMap extends HashMap lt String  List lt Video gt  gt           private static final long serialVersionUID   7023107716981734468L             private static class Video implements Serializable           private static final long serialVersionUID   -446275421030765463L           private String dashUrl          private String videoBitrate          private String audioBitrate          private int videoWidth          private int videoHeight          private long fileSize            Override         public String toString                 return  Video  url     dashUrl      video     videoBitrate      audio     audioBitrate                          width     videoWidth      height     videoHeight      size     fileSize                             public static void main String   args            try               HashMap lt String  List lt Video gt  gt  map   loadJson  sample json   true               Iterator lt Entry lt String  List lt Video gt  gt  gt  lectures   map entrySet   iterator                 while  lectures hasNext                      Entry lt String  List lt Video gt  gt  lecture   lectures next                     System out printf  Lecture   s n   lecture getKey                      for  Video video   lecture getValue                          System out println video                                             catch  IOException e                e printStackTrace                         public static  lt T gt  T parseUnderScoredResponse String json  Class lt T gt  classOfT            try               if  json    null                    return null                            return propertyMapper readValue json  classOfT              catch  JsonParseException e                e printStackTrace              catch  JsonMappingException e                e printStackTrace              catch  IOException e                e printStackTrace                      return null             public static URL pathToUrl String path  boolean isResource  throws MalformedURLException           if  isResource                return JsonHandler class getClassLoader   getResource path                      return new URL  file      path              public static File load String path  boolean isResource  throws MalformedURLException           return load pathToUrl path  isResource               public static File load URL url            try               return new File url toURI               catch  URISyntaxException e                return new File url getPath                           SuppressWarnings  resource       public static String readFile URL url  String charset  throws IOException           return new Scanner url openStream    charset  useDelimiter    A   next               public static String loadJsonString String path  boolean isResource  throws IOException           return readFile path  isResource   UTF-8               public static String readFile String path  boolean isResource  String charset  throws IOException           return readFile pathToUrl path  isResource   charset              public static HashMap lt String  List lt Video gt  gt  loadJson String jsonString  throws IOException           return JsonHandler parseUnderScoredResponse jsonString  MyHashMap class              public static HashMap lt String  List lt Video gt  gt  loadJson String path  boolean isResource  throws IOException           return loadJson loadJsonString path  isResource

User · Answer

You can use Google s Gson library to convert json to Hashmap  Try below code  String jsonString    Your JSON string   HashMap lt String String gt  map   new Gson   fromJson jsonString  new TypeToken lt HashMap lt String  String gt  gt      getType

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This is simple operation no need to use any external library   You can use this class instead     handles even lists   nested lists and json   public class Utility        public static Map lt String  Object gt  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 lt String  Object gt   jsonToMap  JSONObject json  throws JSONException           Map lt String  Object gt  retMap   new HashMap lt String  Object gt              if json    JSONObject NULL                retMap   toMap json                     return retMap              private static Map lt String  Object gt  toMap JSONObject object  throws JSONException           Map lt String  Object gt  map   new HashMap lt String  Object gt              Iterator lt String gt  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 lt Object gt  toList JSONArray array  throws JSONException           List lt Object gt  list   new ArrayList lt Object gt             for int i   0  i  lt  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              To convert your JSON string to hashmap use this     HashMap lt String  Object gt  hashMap   new HashMap lt  gt  Utility jsonToMap response

User · Answer

You could use Gson library  Type type   new TypeToken lt HashMap lt String  String gt  gt       getType    new Gson   fromJson jsonString  type

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consider this json string          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                     using jackson parser   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  lt T gt  T parseUnderScoredResponse String json  Class lt T gt  classOfT            try               if  json    null                    return null                            return underScoreToCamelCaseMapper readValue json  classOfT              catch  JsonParseException e              catch  JsonMappingException e              catch  IOException e                      return null          use following code to parse   HashMap lt String  ArrayList lt Video gt  gt  integerArrayListHashMap                   JsonHandler parseUnderScoredResponse test  MyHashMap class     where MyHashMap is   private static class MyHashMap extends HashMap lt String ArrayList lt Video gt  gt

User · Answer

public class JsonMapExample        public static void main String   args            String json       phonetype     N95     cat     WP              Map lt String  String gt  map   new HashMap lt String  String gt             ObjectMapper mapper   new ObjectMapper             try                 convert JSON string to Map             map   mapper readValue json  new TypeReference lt HashMap lt String  String gt  gt                     System out println map             catch  Exception e                e printStackTrace                        Output     phonetype N95  cat WP    You can see this link it s helpful http   www mkyong com java how-to-convert-java-map-to-from-json-jackson

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Parse the JSONObject and create HashMap  public static void jsonToMap String t  throws JSONException            HashMap lt String  String gt  map   new HashMap lt String  String gt             JSONObject jObject   new JSONObject t           Iterator lt   gt  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           Tested output   json     phonetype   N95   cat   WP   map    cat WP  phonetype N95

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Best way to parse Json to HashMap      public static HashMap lt String  String gt  jsonToMap JSONObject json  throws JSONException               HashMap lt String  String gt  map   new HashMap lt  gt                 try                   Iterator lt String gt  iterator   json keys                     while  iterator hasNext                          String key   iterator next                        String value   json getString key                       map put key  value                                      return map                catch  JSONException e                    e printStackTrace                              return null

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HashMap lt String  String gt  hashMap   new HashMap lt String  String gt     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

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Here is an example of an easy and simple way to create a Hashmap from a JSON string by only using the JSON simple library     quot Collection quot    quot Item Type quot   quot Any quot   quot Name quot   quot A quot   quot Item ID quot   quot 000014 quot    quot Object Name quot   quot System quot    import java io FileReader  import java util HashMap  import java util Iterator   import java util Map    import org json simple JSONObject   import org json simple parser     public class JSONRead    public static void main String   args  throws Exception            Object obj   new JSONParser   parse new FileReader  quot D   other json quot              HashMap lt String String gt  map  new HashMap lt String String gt                 typecasting obj to JSONObject      JSONObject jo    JSONObject  obj           Map Item Id     Map jo get  quot Collection quot                      Iterator lt Map Entry gt  itr1   Item Id entrySet   iterator         while  itr1 hasNext               Map Entry pair   itr1 next             String key    String  pair getKey            String value    String  pair getValue            System out println  pair getKey      quot     quot    pair getValue              map put key  value                  System out println map      System out println map get  quot Item quot

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public Map lt String  String gt  parseJSON JSONObject json  Map lt String  String gt  dataFields  throws JSONException           Iterator lt String gt  keys   json keys            while  keys hasNext                  String key   keys next                String val   null              try                   JSONObject value   json getJSONObject key                   parseJSON value  dataFields                 catch  Exception e                    if  json isNull key                         val                         else                       try                           val   json getString key                         catch  Exception ex                            System out println ex getMessage                                                                        if  val    null                    dataFields put key  val                                   return dataFields

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In Java we can do it using the following statement   We need to use Jackson ObjectMapper for the same and provide the HashMap class as the mapping class  Finally store the result as a HashMap object   HashMap lt String String gt  hashMap   new ObjectMapper   readValue jsonString  HashMap class

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Don t do this yourself  I suggest  Use a library  e g  the Gson library from Google   https   code google com p google-gson

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This worked for me  JSONObject jsonObj   new JSONObject    jsonObj put  quot phonetype quot   quot N95 quot    jsonObj put  quot cat quot   quot WP quot     jsonObj to  Hashmap as following using gson HashMap lt String  Object gt  hashmap   new Gson   fromJson jsonObj toString    HashMap class    package used  lt dependencies gt       lt dependency gt           lt groupId gt org json lt  groupId gt           lt artifactId gt json lt  artifactId gt           lt version gt 20180813 lt  version gt       lt  dependency gt       lt dependency gt           lt groupId gt com google code gson lt  groupId gt           lt artifactId gt gson lt  artifactId gt           lt version gt 2 8 6 lt  version gt       lt  dependency gt   lt  dependencies gt

[java] creating Hashmap from a JSON String

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