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在下面的答案中提到的

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

这是一个虚拟过滤器，应该只执行重定向。

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");
  }
}

以及一个基本的 Spring Boot 应用程序类：

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什么“级别”的 Spring Boot 测试，这是我所做的一些尝试和错误：

选项 1. 尝试使用模拟，例如从这里开始

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，它与选项1有相同的问题

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，我认为需要能够转换为HttpServletRequest：

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

选项 4，由 @m-deinem 建议

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RedirectFilter包含一个错误，它尝试将传入的内容转换HttpServletRequest为 a 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");
  }
}

这两行都使用req而后者应该使用res（这也是异常从字面上告诉你的）。

接下来只需编写一个简单的单元测试，尝试编写集成测试会使事情变得过于复杂。

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());
  }