用来在服务响应返回到客户端之前进行额外处理。
一、定义Filter

package cn.edu.tju.config;import org.apache.dubbo.rpc.Filter;
import org.apache.dubbo.rpc.Result;
import org.apache.dubbo.rpc.Invoker;
import org.apache.dubbo.rpc.Invocation;
import org.apache.dubbo.rpc.RpcException;
import org.apache.dubbo.rpc.AsyncRpcResult;public class AppendedFilter implements Filter {@Overridepublic Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {Result result= invoker.invoke(invocation);// Obtain the returned valueResult appResponse = ((AsyncRpcResult) result).getAppResponse();// Appended valueappResponse.setValue(appResponse.getValue()+"'s customized AppendedFilter");return result;}
}

二、SPI注入Filter

org.apache.dubbo.rpc.Filter的内容如下：

appended=cn.edu.tju.config.AppendedFilter

三、配置文件中指定Filter

server:port: 9953
spring:application:name: dubbosky
dubbo:application:name: dubboskyprotocol:name: dubboport: 28030registry:address: nacos://xx.xx.xx.xx:8848provider:filter: appended