RestController 上的 Java SpringBoot @PathVariable

Question

我有以下@RestController：

package io.github.paulmarcelinbejan.coandaairlines.reservationsystem.adapters.inbound.controller.rest;

import java.util.List;

import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import io.github.paulmarcelinbejan.coandaairlines.reservationsystem.adapters.inbound.impl.rest.CurrencyInboundAdapterRestImpl;
import io.github.paulmarcelinbejan.coandaairlines.reservationsystem.ports.currency.domain.CurrencyDTO;
import io.github.paulmarcelinbejan.davinci.adapters.api.DavinciApiResponse;

import lombok.RequiredArgsConstructor;

@RestController
@RequiredArgsConstructor
@RequestMapping("/api/currency")
public class CurrencyRestController {

    private final CurrencyInboundAdapterRestImpl currencyInboundAdapterRestImpl;

    @GetMapping(value = "/id/{id}", produces = MediaType.APPLICATION_JSON_VALUE)
    public DavinciApiResponse<CurrencyDTO> findById(@PathVariable Integer id) {
        return currencyInboundAdapterRestImpl.findById(id);
    }

    @GetMapping(value = "/code/{code}", produces = MediaType.APPLICATION_JSON_VALUE)
    public DavinciApiResponse<CurrencyDTO> findByCode(@PathVariable String code) {
        return currencyInboundAdapterRestImpl.findByCode(code);
    }

    @GetMapping(value = "/", produces = MediaType.APPLICATION_JSON_VALUE)
    public DavinciApiResponse<List<CurrencyDTO>> findAll() {
        return currencyInboundAdapterRestImpl.findAll();
    }

}

但是当我访问 Swagger 时，它没有显示插入 pathVariable 的空间：

如果我尝试执行，则会出现以下异常：

{
  "status": "KO",
  "errors": {
    "timestampUTC": "2024-04-02T11:24:45.416132Z",
    "exceptionType": "IllegalArgumentException",
    "message": "Name for argument of type [java.lang.Integer] not specified, and parameter name information not available via reflection. Ensure that the compiler uses the '-parameters' flag."
  }
}

邮递员也有同样的问题：

如果我删除 @PathVariable 然后在大摇大摆我可以看到它：

但仍然是同样的错误：

{
  "status": "KO",
  "errors": {
    "timestampUTC": "2024-04-02T11:26:56.186060Z",
    "exceptionType": "IllegalArgumentException",
    "message": "Name for argument of type [java.lang.Integer] not specified, and parameter name information not available via reflection. Ensure that the compiler uses the '-parameters' flag."
  }
}

在另一个项目中，我有类似的@RestController：

package com.hyperbank.types.currency.controller;

import java.util.List;

import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import com.hyperbank.types.currency.dto.CurrencyResponse;
import com.hyperbank.types.currency.dto.CurrencySaveRequest;
import com.hyperbank.types.currency.dto.CurrencyUpdateRequest;
import com.hyperbank.types.currency.mapper.CurrencyMapper;
import com.hyperbank.types.currency.service.CurrencyService;

import io.github.paulmarcelinbejan.toolbox.exception.functional.FunctionalException;
import io.github.paulmarcelinbejan.toolbox.utils.validation.ValidatorUtils;
import io.github.paulmarcelinbejan.toolbox.web.response.OkResponse;
import jakarta.validation.Valid;
import lombok.RequiredArgsConstructor;

@RestController
@RequiredArgsConstructor
@RequestMapping("/api/currency")
public class CurrencyRestController {

    private final CurrencyService currencyService;
    
    private final CurrencyMapper currencyMapper;

    @GetMapping(value = "/{id}", produces = MediaType.APPLICATION_JSON_VALUE)
    public @ResponseBody CurrencyResponse findById(@PathVariable Integer id) throws FunctionalException {
        return currencyMapper.toResponse(currencyService.findById(id));
    }

    @GetMapping(value = "/", produces = MediaType.APPLICATION_JSON_VALUE)
    public @ResponseBody List<CurrencyResponse> findAll() {
        return currencyMapper.toResponses(currencyService.findAll());
    }

}

在那一点上，没有问题：

有什么想法吗？

Answer 1

Reason : This problem arises because Swagger, a tool that helps you document your API, need to know the names of the variable you use in your code. But, sometimes ,the java compiler doesn't save this information by default.So, Swagger get confused and can't show the correct documentation for your API.

Solution : To fix that, you need to tell the java compiler to save this information. once you do that, Swagger will find the pathvariable name and display the correct documentation for your API.

 Add (Maven pom.xml file)
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <compilerArgs>
                    <arg>-parameters</arg>
                </compilerArgs>
            </configuration>
        </plugin>
    </plugins>