why spring.jackson.default-property-inclusion isn’t working in .yml config

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06-10-2024

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Spring Boot's "Spring.jackson.default-property-inclusion" - A Troubleshooting Guide

Problem: You're trying to control which properties are included in your JSON responses using Spring Boot's spring.jackson.default-property-inclusion setting in your .yml file, but it seems to be having no effect. Your JSON output still contains fields you'd prefer to exclude.

Rephrased: You're configuring Spring Boot to only include certain fields in your JSON responses, but it's ignoring your instructions and including everything.

Scenario: Imagine you have a User object with properties like name, age, and password. You only want name and age to be visible in JSON responses. However, even after setting spring.jackson.default-property-inclusion in your application.yml, you still see the password field in your JSON.

Example Code:

spring:
  jackson:
    default-property-inclusion: NON_NULL

Analysis & Clarification:

There are several common reasons why spring.jackson.default-property-inclusion might not work as expected:

1. Conflicting Configuration:

   • You might have other configurations in your application, either in Java code or other .yml files, that override your default-property-inclusion setting.
   • Look for annotations like @JsonInclude(JsonInclude.Include.NON_NULL) on your classes or fields, which might be explicitly controlling inclusion.

2. Overriding the Default:

   • default-property-inclusion sets the default behavior for your JSON serialization. If a field has a specific @JsonInclude annotation on it, that annotation takes precedence over the global setting.

3. Property Existence:

   • spring.jackson.default-property-inclusion is most effective when it's used with inclusion strategies like NON_NULL or NON_EMPTY. If your object contains properties that have default values or are initialized to empty values, they might still appear in your JSON even if you're using NON_NULL or NON_EMPTY.

Troubleshooting:

• Double-Check for Overriding Configurations: Review all your configurations and look for any explicit inclusion/exclusion settings that might be overriding your default-property-inclusion setting.
• Prioritize Annotations: If you need specific inclusion/exclusion behavior, use annotations like @JsonInclude directly on the desired fields for clear control.
• Use NON_NULL or NON_EMPTY Wisely: Ensure your object's properties are not initialized to default values or empty values if you want them to be excluded with NON_NULL or NON_EMPTY.

Additional Value & Best Practices:

• Use @JsonIgnore: For precise control, use the @JsonIgnore annotation on properties that should never be included in JSON responses.
• Consider a custom JsonSerializer: For more complex scenarios, create custom JsonSerializer classes to tailor your JSON output to specific requirements.

References & Resources:

• Spring Boot Documentation: Jackson
• Jackson's @JsonInclude Annotation

By understanding the common pitfalls and applying these troubleshooting steps, you'll be able to effectively use spring.jackson.default-property-inclusion to control the structure of your JSON output in Spring Boot applications.