Java 17 backend fails to handle pipe character in query parameter from frontend request

Backend
1

I’m working on a web application where my React frontend sends requests to a Java 17 backend. I’m running into an issue with a specific character in my query parameters.

The frontend makes a request like this:

http://localhost:3000/api/data/1234?search=categoryName|7

My backend controller looks like this:

@GetMapping(value = "/data/{dataId:[0-9]+}", produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity fetchDataRecord(@PathVariable("dataId") Long dataId,
        @RequestParam(value = "search", required = false) String searchTerm) throws Exception {
    // processing logic here
}

This setup worked perfectly when I was using Java 8. The search parameter would correctly receive the value ‘categoryName|7’ with the pipe symbol.

After upgrading to Java 17, the endpoint returns a 404 error and doesn’t seem to match the route at all. When I remove the pipe character from the parameter value, everything works normally again.

I need to keep both the Java 17 upgrade and the pipe character in my parameter values. Has anyone encountered this issue before?

2

Interesting - did you notice if this started with a specific Tomcat version? I'm curious if it's actually the Spring Boot version causing this rather than Java 17. What version of Spring Boot are you running exactly?

3

This happens because newer Java versions parse URLs more strictly. The pipe character needs to be URL-encoded when you pass it as a query parameter. Your frontend should encode it before sending the request - so categoryName|7 becomes categoryName%7C7. Just use encodeURIComponent() in your React code before adding it to the URL. If you can’t change the frontend right away, there’s a quick fix: add server.tomcat.relaxed-query-chars=| to your application properties. But encoding is the right way to handle this long-term.

4

Same issue here after upgrading. The newer Tomcat version is pickier about query parameters. Quick fix: add server.tomcat.relaxed-query-chars=| to your properties file. But ur better off URL encoding the pipe character on the frontend - just use encodeURIComponent.