java - ContainerRequestFilter 和 ContainerResponseFilter 线程安全吗？

Question

我有下面的代码，它工作正常。我的问题是代码下面的天气是否是线程安全的。通过阅读 Servlet Filter 和 Container*Filter 概念，我感到困惑。

如何使这个过滤器成为线程安全的？

 @Provider
public class ResourceLoggingFilter implements ContainerRequestFilter,   ContainerResponseFilter {

@Context
private ResourceInfo resourceInfo;

@Context
private HttpServletRequest  servletRequest;

@Inject
private java.util.logging.Logger logger;

public void filter(ContainerRequestContext requestContext,  ContainerResponseContext responseContext) throws IOException {
    String stTime = (String) requestContext.getProperty("StartTime"); 
    logger.log(Level.INFO,"<== Leaving Resource Path: "+ requestContext.getUriInfo().getPath());
    logger.log(Level.INFO,"<== Leaving Resource Method: "+  resourceInfo.getResourceMethod().getName());
    logger.log(Level.INFO,"<== Leaving Resource class: "+ resourceInfo.getResourceClass().getCanonicalName());
    logger.log(Level.INFO,"<== Leaving Session id: "+ servletRequest.getSession().getId());
    if (null == stTime || stTime.length() == 0) {
        logger.log(Level.INFO,"start-time not captured or cleared");
        stTime = "0";
    }
    long startTime = Long.parseLong(stTime);
    long executionTime = System.nanoTime() - startTime;
    logger.log(Level.INFO,"Total execution time : "+executionTime+" nano seconds."  );

}

public void filter(ContainerRequestContext requestContext) throws IOException {
    requestContext.setProperty("StartTime", String.valueOf(System.nanoTime())); 
    logger.log(Level.INFO,"==> Entering Resource Path: "+ requestContext.getUriInfo().getPath());
    logger.log(Level.INFO,"==> Entering Resource Method: "+  resourceInfo.getResourceMethod().getName());
    logger.log(Level.INFO,"==> Entering Resource class: "+ resourceInfo.getResourceClass().getCanonicalName());
    logger.log(Level.INFO,"==> Entering Session id: "+ servletRequest.getSession().getId());

}

}

编辑有 private volatile String stTime; 语句好吗，这样 stTime 就可以线程安全了？？

Answer 1

它已经是线程安全的了。 ResourceInfo 和 HttpServletRequest 都是代理(使用本地线程)，而 java.util.Logger 上的方法是线程安全的。

另见:

• Jersey 2: filters and @Context injections
• Request-scoped context field injections into RESTEasy singletons