原因查出来是kafka gg了，进程不在了,注意这条命令也会生成一个进程执行，所以搜索出来的结果如果只有一条，表示kafka进程不在了哦。

 ps -ef | grep kafka

重启kafka，问题解决

bin/kafka-server-start.sh config/server.properties

注意点：不要再返回 chain.filter...，直接return response.setComplete，这样就返回401 了，否则就会继续网后面执行，可能会返回200了。笔者就犯了这个错误

 
  @Component
    public class Session2header extends AbstractNameValueGatewayFilterFactory {
    
        private static final Logger log = LoggerFactory.getLogger(GatewayFilterFactory.class);
    
    
    
        @Override
        public GatewayFilter apply(NameValueConfig config) {
            return (exchange, chain) -> {
    
        //get UID
        ...
                if (!isSucess) {
                    ServerHttpResponse response = exchange.getResponse();
                    response.setStatusCode(HttpStatus.UNAUTHORIZED);
                    return response.setComplete();
    //                return chain.filter(exchange.mutate().response(response).build());
                }

                ServerHttpRequest request = exchange.getRequest().mutate()
                        .header("user_id", uid)
                        .build();
                return chain.filter(exchange.mutate().request(request).build());
            };
        }
    
        private String getUidFromRedis(String token) {
            return userClient.IdByToken(token);
        }
    }

  Caused by: org.apache.catalina.LifecycleException: A child container failed during start
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:950) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:872) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
    ... 6 common frames omitted
Caused by: java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[]]
    at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[na:1.8.0_121]
    at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[na:1.8.0_121]
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:942) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
    ... 8 common frames omitted
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
    ... 6 common frames omitted
Caused by: org.apache.catalina.LifecycleException: Failed to start component [org.apache.catalina.webresources.StandardRoot@3a147ae1]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
    at org.apache.catalina.core.StandardContext.resourcesStart(StandardContext.java:4907) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5042) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
    ... 6 common frames omitted
Caused by: java.lang.IllegalArgumentException: The main resource set specified [/tmp/tomcat-docbase.6227775345915450173.2222] is not valid
    at org.apache.catalina.webresources.StandardRoot.createMainResourceSet(StandardRoot.java:748) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]
    at org.apache.catalina.webresources.StandardRoot.startInternal(StandardRoot.java:706) ~[tomcat-embed-core-8.5.34.jar!/:8.5.34]

最后发现是磁盘满了，
使用下面的命令查看磁盘使用情况

df -h

发现/dev/vda1 磁盘占用100%，然后查看/tmp日志的情况

 du -sh /tmp

发现spring cloud gateway 占用了大量的日志文件
删掉后，发现并没有减少，使用命令

 lsof | grep delete

发现这些删除，但是被程序占用了的文件，只有新启动gateway 程序，日志文件才被删除，解决。

令人激动的java 11终于发布了，而且是长期支持版。

本来想下载个beta版尝试，结果昨天就出了，真是令人激动。

圈圈比较关注的特点摘要：

1. java9 以来的moudule，rt.jar太大了。微服务用不了，以后java 就是轻量级了
2. 可以用令人激动的ZGC
3. 相对9和10 更加稳定。

更多特性发现中。

本来准备用用户的邮箱生成唯一邀请码，但是发现java中String的hashCode并不唯一。

    class Main {
  public static void main(String[] args) {
    String a = new String("FB");
    String b = new String("Ea"); 
    System.out.println(a.hashCode());
    System.out.println(b.hashCode()); 
  }

}

输出结果可以看这个链接 https://repl.it/repls/SameCloudyCgi