Spring Boot 测试过滤器

Question

注意：下面的错误实际上是由过滤器中的拼写错误引起的，请参阅@jccampanero 在下面的回答中提到

我一直在尝试几种不同的方法来测试过滤器，但是我不断收到一个或另一个错误，所以我希望有一些方向。

这是一个虚拟过滤器，应该只进行重定向。

package org.example.filters;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

@Component
public class RedirectFilter implements Filter {
  @Override
  public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
      throws IOException, ServletException {
    HttpServletRequest request = (HttpServletRequest) req;
    HttpServletResponse response = (HttpServletResponse) req;
    chain.sendRedirect("/splash");
  }
}

还有一个基本的 Spring Boot Application 类：

package org.example;

import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class ApplicationClass {

}

我想我只是不清楚我正在尝试做的 Spring Boot 测试的“级别”，这是我做过的一些尝试和错误：

选项 1. 尝试使用模拟，例如来自 here

package org.example.filters;

import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.redirectedUrl;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
import static org.springframework.test.web.servlet.setup.MockMvcBuilders.standaloneSetup;
import org.junit.jupiter.api.Test;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;

public class LocaleFilterIntegrationTestStandalone {

  @Test
  public void whenNoLocaleRedirectToSplash() throws Exception {
    standaloneSetup(new TestController()).addFilters(new RedirectFilter()).build().perform(get("/"))
        .andExpect(status().isFound()).andExpect(redirectedUrl("/splash"));
  }

  @Controller
  private static class TestController {
    @GetMapping("/")
    public String get() {
      return "got it";
    }
  }
}

错误：java.lang.ClassCastException: class org.springframework.mock.web.MockHttpServletRequest cannot be cast to class javax.servlet.http.HttpServletResponse

选项2，尝试使用@WebMvcTest，与选项1有同样的问题

package org.example.filters;

import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.redirectedUrl;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.stereotype.Controller;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.web.bind.annotation.GetMapping;

@WebMvcTest
public class LocaleFilterIntegrationTestWebMvc {
  @Autowired
  private MockMvc mvc;

  @Test
  public void noLanguageShouldRedirectToSplash() throws Exception {
    mvc.perform(get("/")).andExpect(status().isFound()).andExpect(redirectedUrl("/splash"));
  }

  @Controller
  private static class TestController {
    @GetMapping("/")
    public String get() {
      return "got it";
    }
  }
}

错误：java.lang.ClassCastException: class org.springframework.mock.web.MockHttpServletRequest cannot be cast to class javax.servlet.http.HttpServletResponse

选项 3，尝试启动整个上下文，我认为这是能够转换为 HttpServletRequest 所必需的：

package org.example.filters;

import java.net.URI;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
import org.springframework.boot.test.web.client.TestRestTemplate;
import org.springframework.boot.web.server.LocalServerPort;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;

@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
public class LocaleFilterIntegrationTest {
  @LocalServerPort
  private int port;

  @Autowired
  private TestRestTemplate restTemplate;

  @Test
  public void noLanguageShouldRedirectToSplash() throws Exception {
    URI uri = new URI("http", "localhost:" + port, "/", null, null);
    String result = restTemplate.getForObject(uri.toString(), String.class);
    // not sure how, but test for redirect...
  }

  @Controller
  private static class TestController {
    @GetMapping("/")
    public String get() {
      return "got it";
    }
  }
}

错误：class org.apache.catalina.connector.RequestFacade cannot be cast to class javax.servlet.http.HttpServletResponse

@m-deinem 建议的选项 4

package org.example.filters;

import org.junit.jupiter.api.Test;
import org.springframework.mock.web.MockFilterChain;
import org.springframework.mock.web.MockHttpServletRequest;
import org.springframework.mock.web.MockHttpServletResponse;

public class LocaleFilterIntegrationTestPlain {
  private final RedirectFilter redirectFilter = new RedirectFilter();

  @Test
  public void noLanguageShouldRedirectToSplash() throws Exception {
    MockHttpServletRequest req = new MockHttpServletRequest();
    MockHttpServletResponse res = new MockHttpServletResponse();
    MockFilterChain chain = new MockFilterChain();
    redirectFilter.doFilter(req, res, chain);
  }
}

错误：java.lang.ClassCastException: class org.springframework.mock.web.MockHttpServletRequest cannot be cast to class javax.servlet.http.HttpServletResponse

Answer 1

首先您的RedirectFilter 包含一个错误，它尝试将传入的HttpServletRequest 转换为HttpServletResponse，因为您使用了错误的变量。

@Component
public class RedirectFilter implements Filter {
  @Override
  public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
      throws IOException, ServletException {
    HttpServletRequest request = (HttpServletRequest) req;
    HttpServletResponse response = (HttpServletResponse) res;
    res.sendRedirect("/splash");
  }
}

两行都使用req，而后者应该使用res（这也是异常字面意思告诉你的）。

接下来只写一个简单的单元测试，尝试编写集成测试会让事情变得过于复杂。

public class RedirectFilterTest

  private final RedirectFilter filter = new RedirectFilter();

  @Test
  public void redirectTest() {
    MockHttpServletRequest req = new MockHttpServletRequest();
    MockHttpServletResponse res = new MockHttpServletResponse();
    MockFilterChain chain = new MockFilterChain();
 
    filter.doFilter(req, res, chain);

    assertEquals("/splash", res.getRedirectedUrl());
  }

Answer 2

拜托，也许这只是一个错字，但请注意，在您的 RedirectFilter doFilter 方法中，您错误地将变量 req 转换为 HttpServletResponse：

package org.example.filters;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

@Component
public class RedirectFilter implements Filter {
  @Override
  public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
      throws IOException, ServletException {
    HttpServletRequest request = (HttpServletRequest) req;
    // Please, note the incorrect cast
    HttpServletResponse response = (HttpServletResponse) req;
    chain.sendRedirect("/splash");
  }
}

相反，它应该是：

package org.example.filters;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

@Component
public class RedirectFilter implements Filter {
  @Override
  public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
      throws IOException, ServletException {
    HttpServletRequest request = (HttpServletRequest) req;
    HttpServletResponse response = (HttpServletResponse) res;
    chain.sendRedirect("/splash");
  }
}

这很可能是ClassCastException 和测试失败的原因。

一旦解决，@M 提出的解决方案。 Deinum 是一个非常好的和直接的。