How to parse a JSON string to an array using Jackson

Question

I have a String with the following value              key1    value11        key2    value12                key1    value21        key2    value22          And the following class   public class SomeClass       private String key1      private String key2             getters and setters omitted           And I want to parse it to a List lt SomeClass gt  or a SomeClass    Which is the simplest way to do it using Jackson ObjectMapper

User · Answer

I sorted this problem by verifying the json on JSONLint com and then using Jackson  Below is the code for the same    Main Class -  String jsonStr       r n              name      John    r n               city      Berlin    r n                                cars      r n                   FIAT    r n                 Toyata   r n                             r n            job      Teacher   r n           r n        r n                            name      Mark    r n               city      Oslo    r n               cars      r n                                VW    r n                   Toyata   r n             r n                            job      Doctor   r n           r n                  ObjectMapper mapper   new ObjectMapper             MyPojo jsonObj     mapper readValue jsonStr  MyPojo   class            for  MyPojo itr   jsonObj                 System out println  Val of getName is      itr getName                 System out println  Val of getCity is      itr getCity                 System out println  Val of getJob is      itr getJob                 System out println  Val of getCars is      itr getCars       n                POJO   public class MyPojo    private List lt String gt  cars   new ArrayList lt String gt      private String name   private String job   private String city   public List lt String gt  getCars         return cars     public void setCars List lt String gt  cars        this cars   cars     public String getName         return name     public void setName String name        this name   name     public String getJob         return job     public void setJob String job        this job   job     public String getCity         return city     public void setCity String city        this city   city         RESULT -          Val of getName is  John          Val of getCity is  Berlin          Val of getJob is  Teacher          Val of getCars is   FIAT  Toyata             Val of getName is  Mark           Val of getCity is  Oslo           Val of getJob is  Doctor           Val of getCars is   VW  Toyata

User · Answer

I finally got it   ObjectMapper objectMapper   new ObjectMapper    TypeFactory typeFactory   objectMapper getTypeFactory    List lt SomeClass gt  someClassList   objectMapper readValue jsonString  typeFactory constructCollectionType List class  SomeClass class

User · Answer

The complete example with an array  Replace  constructArrayType    by  constructCollectionType    or any other type you need   import java io IOException   import com fasterxml jackson core JsonParseException  import com fasterxml jackson databind ObjectMapper  import com fasterxml jackson databind type TypeFactory   public class Sorting        private String property       private String direction       public Sorting                 public Sorting String property  String direction            this property   property          this direction   direction             public String getProperty             return property             public void setProperty String property            this property   property             public String getDirection             return direction             public void setDirection String direction            this direction   direction             public static void main String   args  throws JsonParseException  IOException           final String json        property     title1      direction     ASC        property     title2      direction     DESC               ObjectMapper mapper   new ObjectMapper            Sorting   sortings   mapper readValue json  TypeFactory defaultInstance   constructArrayType Sorting class            System out println sortings

User · Answer

The other answer is correct  but for completeness  here are other ways   List lt SomeClass gt  list   mapper readValue jsonString  new TypeReference lt List lt SomeClass gt  gt          SomeClass   array   mapper readValue jsonString  SomeClass   class

[java] How to parse a JSON string to an array using Jackson

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