how to convert JSONArray to List of Object using camel-jackson

Question

Am having the String of json array as follow    Compemployes                   id  1001           name   jhon                                        id  1002           name   jhon                 i want to convert this this jsonarray to List lt Empolyee gt    for this i had added the the maven dependency  camel-jackson  and also write the pojo class for employee   but when i try to run my below code    ObjectMapper mapper   new ObjectMapper     List lt Employe gt  list   mapper readValue jsonString  TypeFactory collectionType List class  Employe class      am getting the following exception   org codehaus jackson map JsonMappingException  Can not deserialize instance of java util ArrayList out of START OBJECT token  at  Source  java io StringReader 43caa144  line  1  column  1    can someone pls tell what am missing or doing anyting wrong

User · Answer

It has been answered in http   stackoverflow com questions 15609306 convert-string-to-json-array 33292260 33292260    put string into file jsonFileArr json       username   Hello   email   hello email com   credits       100   twitter username            username   Goodbye   email   goodbye email com       credits   0   twitter username            username   mlsilva   email   mlsilva email com       credits   524   twitter username            username   fsouza   email   fsouza email com       credits   1052   twitter username            public class TestaGsonLista    public static void main String   args    Gson gson   new Gson     try       BufferedReader br   new BufferedReader new FileReader               C   Temp  jsonFileArr json         JsonArray jsonArray   new JsonParser   parse br  getAsJsonArray        for  int i   0  i  lt  jsonArray size    i              JsonElement str   jsonArray get i           Usuario obj   gson fromJson str  Usuario class             use the add method from the list and returns it          System out println obj           System out println str           System out println  -------             catch  IOException e        e printStackTrace

User · Answer

The problem is not in your code but in your json     Compemployes     id  1001  name   jhon      id  1002  name   jhon       this represents an object which contains a property Compemployes which is a list of  Employee  In that case you should create that object like   class EmployeList      private List lt Employe gt  compemployes       with getter an setter      and to deserialize the json simply do   EmployeList employeList   mapper readValue jsonString EmployeList class     If your json should directly represent a list of employees it should look like      id  1001  name   jhon      id  1002  name   jhon      Last remark   List lt Employee gt  list2   mapper readValue jsonString   TypeFactory collectionType List class  Employee class      TypeFactory collectionType is deprecated you should now use something like   List lt Employee gt  list   mapper readValue jsonString  TypeFactory defaultInstance   constructCollectionType List class       Employee class

User · Answer

I also faced the similar problem with JSON output format  This code worked for me with the above JSON format   package com test ameba   import java util List   public class OutputRanges       public List lt Range gt  OutputRanges      public String Message      public String Entity                   return the outputRanges             public List lt Range gt  getOutputRanges             return OutputRanges                         param outputRanges the outputRanges to set             public void setOutputRanges List lt Range gt  outputRanges            OutputRanges   outputRanges                         return the message             public String getMessage             return Message                         param message the message to set             public void setMessage String message            Message   message                         return the entity             public String getEntity             return Entity                         param entity the entity to set             public void setEntity String entity            Entity   entity           package com test    public class Range       public String Name                  return the name             public String getName             return Name                        param name the name to set             public void setName String name            Name   name             public Object   Value                  return the value             public Object   getValue             return Value                        param value the value to set             public void setValue Object   value            Value   value            package com test ameba   import java io IOException   import com fasterxml jackson core JsonParseException  import com fasterxml jackson databind JsonMappingException  import com fasterxml jackson databind ObjectMapper   public class JSONTest                    param args             public static void main String   args               TODO Auto-generated method stub         String jsonString      OutputRanges       Name     ABF MEDICAL RELATIVITY     Value     1 3628407124839714       Name      ABF RX RELATIVITY     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF Unique ID ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF FIRST ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF AMEBA ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF Effective Date ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF AMEBA MODEL     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF UC ER COPAY ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF INN OON DED ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF COINSURANCE ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF PCP SPEC COPAY ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF INN OON OOP MAX ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF IP OP COPAY ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF PHARMACY ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Name      ABF PLAN ADMIN ERR     Value       CPD     SL Limit     Concat   1 1 5 2 2 5 3       Message          Entity   null            ObjectMapper mapper   new ObjectMapper            OutputRanges OutputRanges null          try               OutputRanges   mapper readValue jsonString  OutputRanges class             catch  JsonParseException e                   TODO Auto-generated catch block             e printStackTrace              catch  JsonMappingException e                   TODO Auto-generated catch block             e printStackTrace              catch  IOException e                   TODO Auto-generated catch block             e printStackTrace                      System out println  OutputRanges      OutputRanges            System out println  OutputRanges getOutputRanges        OutputRanges getOutputRanges              for  Range r   OutputRanges getOutputRanges                  System out println r getName

User · Answer

private static String readAll Reader rd  throws IOException       StringBuilder sb   new StringBuilder        int cp      while   cp   rd read       -1          sb append  char  cp             return sb toString          String jsonText   readAll inputofyourjsonstream    JSONObject json   new JSONObject jsonText    JSONArray arr   json getJSONArray  Compemployes      Your arr would looks like                   id  1001           name   jhon                                        id  1002           name   jhon              You can use   arr getJSONObject index    to get the objects inside of the array

User · Answer

I had similar json response coming from client  Created one main list class  and one POJO class

[java] how to convert JSONArray to List of Object using camel-jackson

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