Spring MVC @RequestParam encoding problem on UTF-8

I develop a rest API that serves city information for users. But I’m having problems with @RequestParam charset. I sent some params to the controller which includes Turkish characters. And it didn’t work as expected.

Some of the characters that I have Turkish character problem:

• ı
• ö
• ş
• ç

If you want to check that source code of this project: https://github.com/enesusta/tzone/tree/develop

Here is my request

http://localhost:8080/district?name=diyarbakı

Here is our controller

import com.github.enesusta.tzone.district.service.DistrictsService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import java.io.UnsupportedEncodingException;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.Executor;

@RestController
public class DistrictsController {

    @Autowired
    DistrictsService districtsService;

    @Autowired
    Executor executor;

    @GetMapping("/districts")
    public CompletionStage<List<Districts>> getDistricts() {
        return CompletableFuture.supplyAsync(districtsService.getDistricts(), executor);
    }

    @GetMapping(value = "/district", produces = "application/json;charset=utf-8")
    public CompletionStage<List<Districts>> getDistrictsByName(@RequestParam(name = "name") String districtName) throws UnsupportedEncodingException {
        return CompletableFuture.supplyAsync(districtsService.findDistrictsByCityName(districtName), executor);
    }
}

Here is our service:

import com.github.enesusta.tzone.district.Districts;
import com.github.enesusta.tzone.district.repository.DistrictsRepository;
import org.jboss.logging.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.Locale;
import java.util.function.Supplier;

@Service
public class DefaultDistrictsService implements DistrictsService {

    private final static Logger logger = Logger.getLogger(DefaultDistrictsService.class);

    @Autowired
    DistrictsRepository districtsRepository;

    @Autowired
    Locale locale;

    @Override
    public Supplier<List<Districts>> getDistricts() {
        return () -> districtsRepository.getDistricts();
    }

    @Override
    public Supplier<List<Districts>> findDistrictsByCityName(String cityName) throws UnsupportedEncodingException {
        final String encodedParam = URLEncoder.encode(cityName, StandardCharsets.UTF_8);
        logger.info("encodedParam =" + encodedParam);
        final String upperCasedFirstCharacter = encodedParam.substring(0, 1).toUpperCase(locale);
        final String query = String.format("%s%s", upperCasedFirstCharacter, encodedParam.substring(1));
        logger.info("query = " + query);
        return () -> districtsRepository.findDistrictsByCityName(query);
    }
}

Expected behavior

name=diyarbakı
encodedParam = diyarbakı
query = Diyarbakı

Actual behavior

name = diyarbak%25C4%25B1
encodedParam  = diyarbak%25C4%25B1
query = Diyarbak%25C4%25B1

Environment

• uname -a

Linux DESKTOP-B3CNSC5 4.4.0-18362-Microsoft #836-Microsoft Mon May 05 16:04:00 PST 2020 x86_64 x86_64 x86_64 GNU/Linux

• java -version

openjdk 11.0.6 2020-01-14
OpenJDK Runtime Environment GraalVM CE 20.0.0 (build 11.0.6+9-jvmci-20.0-b02)
OpenJDK 64-Bit Server VM GraalVM CE 20.0.0 (build 11.0.6+9-jvmci-20.0-b02, mixed mode, sharing)

• mvn -version

Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
Maven home: /mnt/c/Java/apache-maven-3.6.3
Java version: 11.0.6, vendor: Oracle Corporation, runtime: /home/phield/java/graalvm-ce-java11-20.0.0
Default locale: en, platform encoding: UTF-8
OS name: "linux", version: "4.4.0-18362-microsoft", arch: "amd64", family: "unix"

• quarkus-ver

<properties>
    <compiler-plugin.version>3.8.1</compiler-plugin.version>
    <maven.compiler.parameters>true</maven.compiler.parameters>
    <maven.compiler.source>11</maven.compiler.source>
    <maven.compiler.target>11</maven.compiler.target>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <quarkus-plugin.version>1.5.2.Final</quarkus-plugin.version>
    <quarkus.platform.artifact-id>quarkus-universe-bom</quarkus.platform.artifact-id>
    <quarkus.platform.group-id>io.quarkus</quarkus.platform.group-id>
    <quarkus.platform.version>1.5.2.Final</quarkus.platform.version>
    <surefire-plugin.version>2.22.1</surefire-plugin.version>
    <jacoco.version>0.8.4</jacoco.version>
  </properties>

[geoand]

I don’t think we’ll be backporting the RESTEasy bump to the 1.8.x line. In any case, 1.9.x isn’t far off

[hacst]

@gsmet I’m not very familiar with the constraints around this in Quarkus. Is there any chance of this fix landing as part of 1.8.2? The bump to 4.5.8 also fixes https://issues.redhat.com/browse/RESTEASY-2678 which I am also encountering.