example with JsonProperty for http://stackoverflow.com/questions/29540396/jackson-custom-serialization-getter

JsonPropertyTest.java

package makasprzak.stackoverflow;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.runners.MockitoJUnitRunner;

import static makasprzak.stackoverflow.JsonPropertyTest.User.Builder.user;
import static org.fest.assertions.Assertions.assertThat;

@RunWith(MockitoJUnitRunner.class)
public class JsonPropertyTest {

   private final ObjectMapper objectMapper = new ObjectMapper();

   @Test
   public void shouldSerializeWithUpperCasedUsername() throws Exception {
      String serialized = objectMapper.writeValueAsString(user()
         .withId(1L)
         .withUsername("macias")
         .build());
      System.out.println(serialized);
      assertThat(serialized).contains("MACIAS").doesNotContain("macias").contains("1");
   }

   @Test
   public void shouldSerializeWithLowerCasedUsername() throws Exception {
      String serialized = objectMapper.writeValueAsString(user()
         .withId(0L)
         .withUsername("macias")
         .build());
      System.out.println(serialized);
      assertThat(serialized).contains("macias").doesNotContain("MACIAS").contains("0").doesNotContain("uppercase");
   }

   public static class User {
      private Long id;
      private String username;

      public Long getId() {
         return id;
      }

      public void setId(Long id) {
         this.id = id;
      }

      public String getUsername() {
         return username;
      }

      public void setUsername(String username) {
         this.username = username;
      }

      @JsonProperty("username")
      public String getUppercaseUsername() {
         return this.id % 2 == 0 ? username : username.toUpperCase();
      }

      public static interface IdStep {
         UsernameStep withId(Long id);
      }

      public static interface UsernameStep {
         BuildStep withUsername(String username);
      }

      public static interface BuildStep {
         User build();
      }


      public static class Builder implements IdStep, UsernameStep, BuildStep {
         private Long id;
         private String username;

         private Builder() {
         }

         public static IdStep user() {
            return new Builder();
         }

         @Override
         public UsernameStep withId(Long id) {
            this.id = id;
            return this;
         }

         @Override
         public BuildStep withUsername(String username) {
            this.username = username;
            return this;
         }

         @Override
         public User build() {
            User user = new User();
            user.setId(this.id);
            user.setUsername(this.username);
            return user;
         }
      }
   }
}