Spring MVC @PathVariable 被视为@RequestParam [重复]

Question

我有一个 spring mvc API（XML 中的配置），里面有多个服务。但是当我尝试使用包含路径变量/{theCurrencyCode} 的@RequestMapping 添加服务时，创建的资源不是我所期望的。

我的预期：

http://localhost:8080/api/v3/parameters/currencies/EUR

什么有效：

http://localhost:8080/api/v3/parameters/currencies/{theCurrencyCode}?theCurrencyCode=EUR

这是我的映射：

import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import java.util.List;

import static org.springframework.http.MediaType.APPLICATION_JSON_VALUE;

@RequestMapping(value = "v3/", produces = { APPLICATION_JSON_VALUE })
public interface ParametersApi {

  @RequestMapping(
      value = "/parameters/currencies/{theCurrencyCode}",
      produces = { "application/json" },
      method = RequestMethod.GET)
  ResponseEntity<List<Currency>> GetCurrencies(@PathVariable("theCurrencyCode") String theCurrencyCode);

}

实施：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;

import java.util.ArrayList;
import java.util.List;

@Controller
public class ParametersApiController implements ParametersApi{

  private final CurrenciesService service;

  @Autowired
  public ParametersApiController(CurrenciesService service) {
    this.service = service;
  }

  @Override
  public ResponseEntity<List<Currency>> GetCurrencies(String code) {

    final List<Currency> currencies = service.getCurrencies(code);

    return new ResponseEntity<>(currencies, HttpStatus.OK);
  }
}

Swagger UI 确认了这一点，将 theCurrencyCode 视为“参数类型”query 而不是 path。

如何让我的@PathVariable 工作？

Answer 1

您的方法实现中缺少路径变量。 所以要修复，你需要这样写：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;

import java.util.ArrayList;
import java.util.List;

@Controller
public class ParametersApiController implements ParametersApi{

    private final CurrenciesService service;

    @Autowired
    public ParametersApiController(CurrenciesService service) {
        this.service = service;
    }

    @Override
    public ResponseEntity<List<Currency>> GetCurrencies(@PathVariable String theCurrencyCode) {
        final List<Currency> currencies = service.getCurrencies(theCurrencyCode);
        return new ResponseEntity<>(currencies, HttpStatus.OK);
    }
}

Answer 2

带注释的方法参数并未传递给所有实现。所以这就是你需要重新声明它的原因。

Answer 3

将您的界面更改为：

import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import java.util.List;

import static org.springframework.http.MediaType.APPLICATION_JSON_VALUE;

@RequestMapping(value = "v3/", produces = { APPLICATION_JSON_VALUE })
public interface ParametersApi {

  @RequestMapping(
      value = "/parameters/currencies/{theCurrencyCode}",
      produces = { "application/json" },
      method = RequestMethod.GET)
  ResponseEntity<List<Currency>> GetCurrencies(@PathVariable String theCurrencyCode);

}

您的路径变量名称和 URL 路径名称应该匹配。无需在括号中指定参数名称。