How to create custom filter in Spring Boot

Yes, in Spring Boot, you can add a custom filter to your web application using the @Component and @Order annotations.

Here’s an example of how you can create a custom filter:

1. Create a new class and annotate it with @Component to mark it as a Spring bean.

@Component
public class CustomFilter implements Filter {
    // Implement the methods of the Filter interface
}

2. Implement the methods of the javax.servlet.Filter interface in your custom filter class.

@Component
public class CustomFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // Initialization logic
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        // Filter logic
        chain.doFilter(request, response);
    }

    @Override
    public void destroy() {
        // Cleanup logic
    }
}

3. Use the @Order annotation to specify the order in which the filter should be applied. Lower numbers are processed first.

@Component
@Order(1)
public class CustomFilter implements Filter {
    // Implement the methods of the Filter interface
}

4. Spring Boot will automatically register your custom filter with the servlet container, and it will be applied to all incoming requests.

Note that you can also use the @WebFilter annotation instead of @Component to define a filter class. The @WebFilter annotation is a standard Java EE annotation, but it works in Spring Boot as well.

How to create custom filter in Spring Boot