Jackson-annotations-jsonserialize

Jackson Annotations-@JsonSerialize

*@ JsonSerialize* は、カスタムシリアライザーを指定してjsonオブジェクトをマーシャリングするために使用されます。

@JsonSerializeを使用した例

import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;

public class JacksonTester {
   public static void main(String args[]) throws ParseException {
      ObjectMapper mapper = new ObjectMapper();
      SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy");
      try {
         Student student = new Student("Mark", 1, dateFormat.parse("20-11-1984"));
         String jsonString = mapper
            .writerWithDefaultPrettyPrinter()
            .writeValueAsString(student);
         System.out.println(jsonString);
      }
      catch (IOException e) {
         e.printStackTrace();
      }
   }
}
class Student {
   private String name;
   private int rollNo;
   @JsonSerialize(using = CustomDateSerializer.class)
   private Date dateOfBirth;
   public Student(String name, int rollNo, Date dob){
      this.name = name;
      this.rollNo = rollNo;
      this.dateOfBirth = dob;
   }
   public String getName(){
      return name;
   }
   public int getRollNo(){
      return rollNo;
   }
   public Date getDateOfBirth(){
      return dateOfBirth;
   }
}
class CustomDateSerializer extends StdSerializer<Date> {
   private static final long serialVersionUID = 1L;
   private static SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyyy");
   public CustomDateSerializer() {
      this(null);
   }
   public CustomDateSerializer(Class<Date> t) {
      super(t);
   }
   @Override
   public void serialize(Date value,
      JsonGenerator generator, SerializerProvider arg2) throws IOException {
      generator.writeString(formatter.format(value));
   }
}

出力

{
   "name" : "Mark",
   "rollNo" : 1,
   "dateOfBirth" : "20-11-1984"
}