dubbo异常正确处理姿势，dubbo异常处理机制

1、抛出问题

 dubbo在Provider端抛出自定义异常的时候会自动转换成RunTimeException异常自定义异常tostring放在RunTimeException的msg中，导致我们在调用的时候不能正确获取到我们想要的异常或者信息。

2、原因分析

Dubbo异常处理类ExceptionFilter

@Activate(
    group = {"provider"}
)
public class ExceptionFilter implements Filter {
    private final Logger logger;

    public ExceptionFilter() {
        this(LoggerFactory.getLogger(ExceptionFilter.class));
    }

    public ExceptionFilter(Logger logger) {
        this.logger = logger;
    }

    public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
        try {
            Result result = invoker.invoke(invocation);
            if (result.hasException() && GenericService.class != invoker.getInterface()) {
                try {
                    Throwable exception = result.getException();
                    // 如果是checked异常，直接抛出
                    if (!(exception instanceof RuntimeException) && exception instanceof Exception) {
                        return result;
                    } else {
                        try {
                        // 在方法签名上有声明，返回
                            Method method = invoker.getInterface().getMethod(invocation.getMethodName(), invocation.getParameterTypes());
                            Class<?>[] exceptionClassses = method.getExceptionTypes();
                            Class[] arr$ = exceptionClassses;
                            int len$ = exceptionClassses.length;

                            for(int i$ = 0; i$ < len$; ++i$) {
                                Class<?> exceptionClass = arr$[i$];
                                if (exception.getClass().equals(exceptionClass)) {
                                    return result;
                                }
                            }
                        } catch (NoSuchMethodException var11) {
                            return result;
                        }

                        this.logger.error("Got unchecked and undeclared exception which called by " + RpcContext.getContext().getRemoteHost() + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName() + ", exception: " + exception.getClass().getName() + ": " + exception.getMessage(), exception);
                        // 异常类和接口类在同一jar包里，返回
                        String serviceFile = ReflectUtils.getCodeBase(invoker.getInterface());
                        String exceptionFile = ReflectUtils.getCodeBase(exception.getClass());
                        if (serviceFile != null && exceptionFile != null && !serviceFile.equals(exceptionFile)) {
                            String className = exception.getClass().getName();
                            // 如果是是JDK自带的异常，返回
                            if (!className.startsWith("java.") && !className.startsWith("javax.")) {
                            //把异常转换成RuntimeException返回
                                return (Result)(exception instanceof RpcException ? result : new RpcResult(new RuntimeException(StringUtils.toString(exception))));
                            } else {
                                return result;
                            }
                        } else {
                            return result;
                        }
                    }
                } catch (Throwable var12) {
                    this.logger.warn("Fail to ExceptionFilter when called by " + RpcContext.getContext().getRemoteHost() + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName() + ", exception: " + var12.getClass().getName() + ": " + var12.getMessage(), var12);
                    return result;
                }
            } else {
                return result;
            }
        } catch (RuntimeException var13) {
            this.logger.error("Got unchecked and undeclared exception which called by " + RpcContext.getContext().getRemoteHost() + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName() + ", exception: " + var13.getClass().getName() + ": " + var13.getMessage(), var13);
            throw var13;
        }
    }
}

3、解决办法

所以能直接抛出的异常有：

1、实现了GenericService接口
2、checked异常
3、在方法签名上有声明
4、异常类和接口类在同一jar包里
5、JDK自带的异常
6、是Dubbo本身的异常

解决办法二：自定义dubbo的异常filter

从ExtensionLoader类中可以发现，spi加载的目录可以看到

按照dubbo的目录创建Filter。建议直接把dubbo源码中的copy过来。目录结构

把Filter中的内容替换成我们自定义的Filter路径：exception=com.gaol.test.config.DubboExceptionFilter

exception=com.alibaba.dubbo.rpc.filter.ExceptionFilter

自定义Filter

@Log4j2
@Activate(group = {"provider"})
public class DubboExceptionFilter implements Filter {
    

    public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
        try {
            Result result = invoker.invoke(invocation);
            if (result.hasException() && GenericService.class != invoker.getInterface()) {
                try {
                    Throwable exception = result.getException();
                    if (!(exception instanceof RuntimeException) && exception instanceof Exception) {
                        return result;
                    } else {
                        try {
                            Method method = invoker.getInterface().getMethod(invocation.getMethodName(), invocation.getParameterTypes());
                            Class<?>[] exceptionClassses = method.getExceptionTypes();
                            Class[] arr$ = exceptionClassses;
                            int len$ = exceptionClassses.length;

                            for(int i$ = 0; i$ < len$; ++i$) {
                                Class<?> exceptionClass = arr$[i$];
                                if (exception.getClass().equals(exceptionClass)) {
                                    return result;
                                }
                            }
                        } catch (NoSuchMethodException var11) {
                            return result;
                        }

                        log.error("Got unchecked and undeclared exception which called by " + RpcContext.getContext().getRemoteHost() + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName() + ", exception: " + exception.getClass().getName() + ": " + exception.getMessage(), exception);
                        String serviceFile = ReflectUtils.getCodeBase(invoker.getInterface());
                        String exceptionFile = ReflectUtils.getCodeBase(exception.getClass());
                        if (serviceFile != null && exceptionFile != null && !serviceFile.equals(exceptionFile)) {
                            String className = exception.getClass().getName();
                            //如果是我们系统自定义异常直接返回
                            if(className.startsWith("com.gaol.test.exception")){
                                return result;
                            }
                            if (!className.startsWith("java.") && !className.startsWith("javax.")) {
                                return (Result)(exception instanceof RpcException ? result : new RpcResult(new RuntimeException(StringUtils.toString(exception))));
                            } else {
                                return result;
                            }
                        } else {
                            return result;
                        }
                    }
                } catch (Throwable var12) {
                    log.warn("Fail to ExceptionFilter when called by " + RpcContext.getContext().getRemoteHost() + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName() + ", exception: " + var12.getClass().getName() + ": " + var12.getMessage(), var12);
                    return result;
                }
            } else {
                return result;
            }
        } catch (RuntimeException var13) {
            log.error("Got unchecked and undeclared exception which called by " + RpcContext.getContext().getRemoteHost() + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName() + ", exception: " + var13.getClass().getName() + ": " + var13.getMessage(), var13);
            throw var13;
        }
    }
}

共同进步！！！！！！！！！