java - How to ignore enum fields in Jackson JSON-to-Object mapping? -

i have json object like:

{"name":"john", "grade":"a"} 

or

{"name":"mike", "grade":"b"} 

or

{"name":"simon", "grade":"c"} 

etc

i trying map above json to:

@jsonignoreproperties(ignoreunknown = true) public class employee{       @jsonignoreproperties(ignoreunknown = true)       public enum grade{ a, b, c }       grade grade;       string name;    public grade getgrade() {     return grade;   }    public void setgrade(grade grade) {     this.grade = grade;   }    public string getname() {     return name;   }    public void setname(string name) {     this.name = name;   } } 

the above mapping works fine in future there more "grade" types let d,e etc breaks existing mapping , throws following exception

05-08 09:56:28.130: w/system.err(21309): org.codehaus.jackson.map.jsonmappingexception: can not construct instance of employee string value 'd': value not 1 of declared enum instance names 

is there way ignore unknown fields in enum types?

thanks

i think should define external deserializer grade enum.

i added additional field enum - unknown:

enum grade {     a, b, c, unknown;      public static grade fromstring(string value) {         (grade grade : values()) {             if (grade.name().equalsignorecase(value)) {                 return grade;             }         }          return unknown;     } } class employee {      @jsondeserialize(using = gradedeserializer.class)     private grade grade;     private string name;      public grade getgrade() {         return grade;     }      public void setgrade(grade grade) {         this.grade = grade;     }      public string getname() {         return name;     }      public void setname(string name) {         this.name = name;     }      @override     public string tostring() {         return "employee [grade=" + grade + ", name=" + name + "]";     } } 

now, parser that:

class gradedeserializer extends jsondeserializer<grade> {     @override     public grade deserialize(jsonparser parser, deserializationcontext context)             throws ioexception, jsonprocessingexception {         return grade.fromstring(parser.getvalueasstring());     } } 

example usage:

public class jacksonprogram {      public static void main(string[] args) throws exception {         objectmapper objectmapper = new objectmapper();         jsonfactory jsonfactory = new jsonfactory();         jsonparser parser = jsonfactory                 .createjsonparser("{\"name\":\"john\", \"grade\":\"d\"}");         employee employee = objectmapper.readvalue(parser, employee.class);         system.out.println(employee);     }  } 

output:

employee [grade=unknown, name=john] 

if don't want add additional field, return null example.