# 自定义 handler 参数传递 ServiceComb Java Chassis 中 **自定义 Handler** 处理完数据如何传递给 **Controller** > * 关于 **Context** 传递消息 可以参考官方地址 https://docs.servicecomb.io/java-chassis/zh_CN/general-development/context/ > > * 如何 `扩展自定义 Handler` 可参考 https://docs.servicecomb.io/java-chassis/zh_CN/references-handlers/intruduction/#_2 demo 示例 **https://github.com/apache/servicecomb-java-chassis/blob/master/demo/demo-register-url-prefix/demo-register-url-prefix-server/src/main/java/org/apache/servicecomb/demo/prefix/AccessLogHandler.java** > > ### 1. 自定义 Handler 设置 参数 ```java public class AccessLogHandler implements Handler { @Override public void handle(Invocation invocation, AsyncResponse asyncResp) throws Exception { // 自定义设置参数 invocation.addContext("tt", "user-defined"); } } ``` ### 2. Controller 里面获取参数 ```java @GetMapping(path = "/getName") public String getName(@RequestParam(name = "name") String name) { String contextParam = ContextUtils.getInvocationContext().getContext("tt"); return contextParam + "_" + name; } ```

建议自己debug 下开源的代码.  这个全局一搜就出来了

可以在 edge 加一个 HttpClientFilter ```java /* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import org.apache.commons.lang3.StringUtils; import org.apache.servicecomb.common.rest.filter.HttpClientFilter; import org.apache.servicecomb.core.Invocation; import org.apache.servicecomb.foundation.vertx.http.HttpServletRequestEx; import org.apache.servicecomb.foundation.vertx.http.HttpServletResponseEx; import org.apache.servicecomb.swagger.invocation.Response; import java.util.Arrays; import java.util.List; public class EdgeAddHeader implements HttpClientFilter { private static final List HEADER_KEY = Arrays.asList("header", "test", "User-Agent"); @Override public int getOrder() { return 0; } @Override public void beforeSendRequest(Invocation invocation, HttpServletRequestEx requestEx) { HttpServletRequestEx oldRequest = invocation.getRequestEx(); HEADER_KEY.forEach(key -> { requestEx.addHeader(key, StringUtils.isEmpty(oldRequest.getHeader(key)) ? "default_header_xxx" : oldRequest.getHeader(key)); }); } @Override public Response afterReceiveResponse(Invocation invocation, HttpServletResponseEx responseEx) { return null; } } ```

明显是会点 spring boot 做业务就感觉自己 很牛逼的小白, 和我去年没毕业的时候差不多