[Solved] Jackson: No suitable constructor found for type

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1. I covert list to json and json back to list

   
   ObjectMapper objectMapper = new ObjectMapper();
   
               // Convert list to json
               String json = objectMapper.writeValueAsString(personList);
   
               System.out.println(json);
   
               // Convert json back to list
               List<Person> person = objectMapper.readValue(json, new TypeReference<List<Person>>(){});
   
   

   Is resullt:

   run:
   [{“firstName”:”Mike”,”lastName”:”harvey1″,”age”:34,”contact”:”001894536″},{“firstName”:”Mike”,”lastName”:”harvey2″,”age”:34,”contact”:”001894536″},{“firstName”:”Mike”,”lastName”:”harvey3″,”age”:34,”contact”:”001894536″},{“firstName”:”Mike”,”lastName”:”harvey4″,”age”:34,”contact”:”001894536″}]
   org.codehaus.jackson.map.JsonMappingException: No suitable constructor found for type [simple type, class gson.Main$Person]: can not instantiate from JSON object (need to add/enable type information?)
   at [Source: java.io.StringReader@4566e5bd; line: 1, column: 3]
   at org.codehaus.jackson.map.JsonMappingException.from(JsonMappingException.java:163)
   at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObjectUsingNonDefault(BeanDeserializer.java:740)
   at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:683)
   at org.codehaus.jackson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:580)
   at org.codehaus.jackson.map.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:217)
   at org.codehaus.jackson.map.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:194)
   at org.codehaus.jackson.map.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:30)
   at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2723)
   at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1861)
   at gson.Main.main(Main.java:48)
   BUILD SUCCESSFUL (total time: 0 seconds)

   Reply

2. Hi,

   I wrote the problem in last post.
   I got the solution. we have to use jackson2.

   Regards,
   Vijay

   Reply

3. It solve the problem. But I don’t want to use default Constructor. As I am using Jackson annotation (@JsonDeserialize) to deserialize and serialize.

   Below, I am writing the sample code:

   @JsonInclude(Include.NON_NULL)
   @JsonDeserialize(builder = Employee.Builder.class)
   public final class Employee {
   private final String name;
   public Employee(final String name) {
   this.name = name;
   }
   public String getName() {
   return name;
   }
   public static final class Builder {
   private final String name;
   public Builder() {
   this.name = “”;
   }

   public Builder setName(
   final String name) {
   this.name = name;
   return this;
   }
   public Employee build() {
   return new Employee (name);
   }
   }
   }

   WebSerive:
   @Produces(MediaType.APPLICATION_JSON)
   @Consumes(MediaType.APPLICATION_JSON)
   public class Resource {
   @POST
   @Path(PathConstants.EmployeePath)
   public Response postEmployee(final Employee employee) {
   //some operation.
   }

   Error: Getting the same error as Lokesh mentioned above.

   Thanks

   Reply