Mastering Jackson: 5 Ways to Exclude Fields in Spring Boot JSON

Introduction

In Spring Boot development, JSON is the primary data exchange format between front‑end requests and back‑end responses. Jackson, the default JSON processor, offers powerful features for converting between objects and JSON. However, not all object fields should be serialized or deserialized, especially sensitive data such as passwords.

This article presents five practical methods to ignore JSON fields using Jackson.

1. Overview

Jackson provides several annotations and configurations to control field inclusion during JSON conversion. The following sections demonstrate each method with code snippets and expected output.

2. Practical Cases

2.1 Class‑Level Field Ignoring

Use @JsonIgnoreProperties on a class to specify fields that should be omitted.

@JsonIgnoreProperties(value = {"password", "idNo"})
public class User {
  private Long id;
  private String name;
  private String password;
  private String idNo;
  private String address;
}

Controller example:

@GetMapping("/query")
public User query() {
  return new User(1L, "Spring Boot实战案例200讲", "1234567890", "1828381828225677", "四川乌鲁木齐");
}

Result: the password and idNo fields are omitted.

2.2 Field‑Level Ignoring

Apply @JsonIgnore directly on the fields that should be excluded.

public class User {
  private Long id;
  private String name;
  @JsonIgnore
  private String password;
  @JsonIgnore
  private String idNo;
  private String address;
}

The same endpoint now returns JSON without the annotated fields.

2.3 Ignoring All Fields of a Type

Annotate a class with @JsonIgnoreType to skip all its fields during serialization.

@JsonIgnoreType
public class Score {
  private Long userId;
  private double score;
}

Include Score in User and the entire Score object will be ignored in the JSON output.

2.4 Using a Filter to Exclude Fields

Define a custom PropertyFilter and register it via Jackson2ObjectMapperBuilderCustomizer.

@Component
public class JsonFilterConfig implements Jackson2ObjectMapperBuilderCustomizer {
  @Override
  public void customize(Jackson2ObjectMapperBuilder builder) {
    SimpleBeanPropertyFilter theFilter = SimpleBeanPropertyFilter.serializeAllExcept("password", "idNo");
    FilterProvider filters = new SimpleFilterProvider().addFilter("userFilter", theFilter);
    builder.filters(filters);
  }
}

Apply the filter to the class:

@JsonFilter("userFilter")
public class User {
  private Long id;
  private String name;
  private String password;
  private String idNo;
  private String address;
  private Score score;
}

2.5 @JsonView Filtering

The @JsonView annotation allows selective serialization based on view classes, enabling different field sets for public or internal APIs. (Detailed usage is linked in the original article.)

2.6 Custom Serializer

Implement a custom serializer by extending JsonSerializer<T> and overriding serialize to manually write desired fields.

public class UserSerializer extends JsonSerializer<User> {
  @Override
  public void serialize(User user, JsonGenerator gen, SerializerProvider serializers) throws IOException {
    gen.writeStartObject();
    gen.writeNumberField("id", user.getId());
    gen.writeStringField("name", user.getName());
    gen.writeStringField("address", user.getAddress());
    gen.writeEndObject();
  }
}

Annotate the class:

@JsonSerialize(using = UserSerializer.class)
public class User {
  // fields ...
}

Result Screenshots