Question

DelegatingFilterProxy有两个我可以在我的应用程序中使用的构造函数

new DelegatingFilterProxy(String beanName);
new DelegatingFilterProxy(Filter delegate);

在我的webappIntializer中，我有以下内容。（请参阅下面的完整代码）。

servletContext.addFilter("counterMetricsFilter", new DelegatingFilterProxy("counterMetricsFilter").addMappingForUrlPatterns(null,
                false, MAPPING_URL);

我不确定DelegatingFilterProxy在我的情况下是否正常运作。

Controller

@Controller
@RequestMapping("/counter")
public class CounterController {

@Autowired
CounterManager manager;

 @RequestMapping(value = "/counterMetrics", method = RequestMethod.GET)
    @ResponseBody
    public Map getFeatureStatus(final HttpServletResponse response) {
        System.out.println("returning feautre status");
        return manager.getQueryCounts();
    }
}

Manager

@Service
public class CounterManager {

private Map<String,Integer> queryCounts =
            new ConcurrentHashMap<String,Integer>(1000);

int threshold;
long timestamp;

 @Autowired
  public CounterManager(@Value("${healthThreshold: 10}")
                                 int threshold) {
      this.threshold = threshold * MEGABYTES;
      this.timestamp = System.currentTimeMillis();
  }


 public void incrementRequestCounter(String urlPath){
     Integer oldVal, newVal;
     do {
       oldVal = queryCounts.get(model);
       newVal = (oldVal == null) ? 1 : (oldVal + 1);
     } while (!queryCounts.replace(model, oldVal, newVal));
 }

public Map<StatusUrlModel, Integer> getQueryCounts() {
    return queryCounts;
}

}

Filter

@Order(Ordered.HIGHEST_PRECEDENCE)
@Component(value="counterMetricsFilter")
public class CounterMetricsFilter extends OncePerRequestFilter {

    @Autowired
    CounterManager manager;

    @Override
    protected void doFilterInternal(HttpServletRequest request,
            HttpServletResponse response, FilterChain chain) throws ServletException,
            IOException {
        String path = new UrlPathHelper().getPathWithinApplication(request);
        try {
            chain.doFilter(request, response);
        }
        finally {
            recordMetrics(request, path);
        }
    }

   private void recordMetrics(String path) {
        try {
        manager.incrementRequestCounter(url);
        }
        catch (Exception ex){
            System.out.println("exception is thrown " + ex.getCause());
            ex.printStackTrace();
        }
    }
}

的DelegatingFilterProxy

public class myAppWebAppInitializer implements WebApplicationInitializer {

             private static final String CONFIG_LOCATION = "com.myapp.sample.config";
            public static final String MAPPING_URL = "/*";

            @Override
            public void onStartup(ServletContext servletContext) throws ServletException {

     AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
    context.setConfigLocation(CONFIG_LOCATION);

                servletContext.addListener(new ContextLoaderListener(context));

                servletContext.addFilter("counterMetricsFilter", new DelegatingFilterProxy("counterMetricsFilter").addMappingForUrlPatterns(null,
            false, MAPPING_URL);

                ServletRegistration.Dynamic dispatcher = servletContext.addServlet("DispatcherServlet", new DispatcherServlet(
                        context));
                dispatcher.setLoadOnStartup(1);
                dispatcher.addMapping(MAPPING_URL);
            }

    }

注意：容器启动正常。请求通过罚款。因为上面manager.incrementRequestCounter(url)中的这一行CounterMetricsFilter正在抛出异常，而我正在捕捉它，我看到空洞的回应。我怀疑delegateFilterProxy不是autowiring正确。

另请注意，manager bean已在Application Context中加载，因为我可以在CounterController中检查bean。

我无法修复它。这里的任何提示都会非常有用。

修改

更改为constructor injection而不是CounterMetricsFilter中的字段注入，我得到以下异常。

//我删除了上面的no-arg构造函数 @Autowired public CounterMetricsFilter（HealthManager healthManager）{ this.healthManager = healthManager; }

栈跟踪

SEVERE: Exception starting filter counterMetricsFilter
org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'counterMetricsFilter' is defined
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:638)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1159)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:282)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:979)
    at org.springframework.web.filter.DelegatingFilterProxy.initDelegate(DelegatingFilterProxy.java:324)
    at org.springframework.web.filter.DelegatingFilterProxy.initFilterBean(DelegatingFilterProxy.java:235)
    at org.springframework.web.filter.GenericFilterBean.init(GenericFilterBean.java:199)
    at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:281)
    at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:111)
    at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4775)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5452)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633)
    at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1113)
    at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1671)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
  [1]: http://stackoverflow.com/questions/32573742/why-is-autowired-bean-null-in-filter-in-this-spring-application

Answer 1

我在上面的代码片段中没有看到配置类本身，因此列出了如何使DelegatingFilterProxy与Spring Java Config一起使用的一般解决方案。

<强>初始化程序

public class MyWebAppInitializer implements WebApplicationInitializer {
    ...
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        ...
        servletContext.addFilter("myFilter", new DelegatingFilterProxy("myFilter"))
                .addMappingForUrlPatterns(null, true, "/*");
        ...
    }
    ...
}

过滤

public class MyFilter implements Filter { ... // I added this parameter just as example of how Spring-managed dependencies // could be injected. Note, there is no any annotations in this class. private String someParameter; public MyFilter(String someParameter) { this.someParameter = someParameter; } ... }

<强>配置

@Configuration @EnableWebMvc @PropertySource(value = { "classpath:my.properties" }) @Import({ PropertySourcesPlaceholderConfigurer.class }) public class MyConfig { ... @Bean public MyFilter myFilter(@Value("${someParameter}") String someParameter) { return new MyFilter(someParameter); } ... }

希望它对某人有用。

如何在Java配置中使用delegatingFilterproxy？

1 个答案: