Set a header to all responses in Spring Boot

This post will discuss how to set a header to all responses in a Spring Boot application.

In the previous post, we have covered how to set a header on a single response using HttpServletResponse or ResponseEntity. This post will discuss how to set a custom header to all responses in our application.

The idea is to use a filter. By using a filter, we can avoid adding responses manually for each of the mapping methods. There are several ways to register a filter class and set a response header in the Spring Boot application.

1. Extending OncePerRequestFilter

To create a custom filter, we can also extend the abstract class OncePerRequestFilter and annotate the filter with @Component. To set a header to each response, use addHeader() method of the HttpServletResponse interface. This is demonstrated below:

import org.springframework.stereotype.Component;

import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

@Component

public class FirstFilter extends OncePerRequestFilter {

@Override

protected void doFilterInternal(HttpServletRequest httpServletRequest,

HttpServletResponse httpServletResponse,

FilterChain filterChain)

throws ServletException, IOException {

httpServletResponse.addHeader("Access-Control-Allow-Origin", "*");

filterChain.doFilter(httpServletRequest, httpServletResponse);

}

2. Implementing Filter Interface

We can also implement the Filter interface and annotate the filter with one of the Spring stereotypes, such as @Component for Spring to recognize it. To set the custom header to each response, use addHeader() method of the HttpServletResponse interface.

import org.springframework.stereotype.Component;

import javax.servlet.*;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

@Component

public class FirstFilter implements Filter {

@Override

public void doFilter(ServletRequest request,

ServletResponse response,

FilterChain chain) throws IOException, ServletException

{

HttpServletRequest req = (HttpServletRequest) request;

HttpServletResponse res = (HttpServletResponse) response;

res.addHeader("Access-Control-Allow-Origin", "*");

chain.doFilter(req, res);

}

That’s all about setting a header to all responses in Spring Boot.

Set a header to all responses in Spring Boot

1. Extending OncePerRequestFilter

2. Implementing Filter Interface

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