面试官问我，使用Dubbo有没有遇到一些坑？我笑了…

1public class HelloException extends RuntimeException {
2
3    public HelloException() {
4    }
5
6    public HelloException(String message) {
7        super(message);
8    }
9
10}

1public interface DemoService {
2
3    String sayHello(String name);
4
5}

1public class DemoServiceImpl implements DemoService {
2
3    public String sayHello(String name) {
4        throw new HelloException("公众号:肥朝");
5    }
6
7}

1public class DemoAction {
2
3    private DemoService demoService;
4
5    public void setDemoService(DemoService demoService) {
6        this.demoService = demoService;
7    }
8
9    public void start() throws Exception {
10        try {
11            String hello = demoService.sayHello("公众号:肥朝");
12        } catch (HelloException helloException) {
13            System.out.println("这里捕获helloException异常");
14        }
15    }
16
17}

1com.alibaba.dubbo.rpc.filter.ExceptionFilter.invoke(ExceptionFilter.java:108)

1    public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
2        try {
3            Result result = invoker.invoke(invocation);
4            if (result.hasException() && GenericService.class != invoker.getInterface()) {
5                try {
6                    Throwable exception = result.getException();
7
8                    // 如果是checked异常，直接抛出
9                    if (! (exception instanceof RuntimeException) && (exception instanceof Exception)) {
10                        return result;
11                    }
12                    // 在方法签名上有声明，直接抛出
13                    try {
14                        Method method = invoker.getInterface().getMethod(invocation.getMethodName(), invocation.getParameterTypes());
15                        Class<?>[] exceptionClassses = method.getExceptionTypes();
16                        for (Class<?> exceptionClass : exceptionClassses) {
17                            if (exception.getClass().equals(exceptionClass)) {
18                                return result;
19                            }
20                        }
21                    } catch (NoSuchMethodException e) {
22                        return result;
23                    }
24
25                    // 未在方法签名上定义的异常，在服务器端打印ERROR日志
26                    logger.error("Got unchecked and undeclared exception which called by " + RpcContext.getContext().getRemoteHost()
27                            + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName()
28                            + ", exception: " + exception.getClass().getName() + ": " + exception.getMessage(), exception);
29
30                    // 异常类和接口类在同一jar包里，直接抛出
31                    String serviceFile = ReflectUtils.getCodeBase(invoker.getInterface());
32                    String exceptionFile = ReflectUtils.getCodeBase(exception.getClass());
33                    if (serviceFile == null || exceptionFile == null || serviceFile.equals(exceptionFile)){
34                        return result;
35                    }
36                    // 是JDK自带的异常，直接抛出
37                    String className = exception.getClass().getName();
38                    if (className.startsWith("java.") || className.startsWith("javax.")) {
39                        return result;
40                    }
41                    // 是Dubbo本身的异常，直接抛出
42                    if (exception instanceof RpcException) {
43                        return result;
44                    }
45
46                    // 否则，包装成RuntimeException抛给客户端
47                    return new RpcResult(new RuntimeException(StringUtils.toString(exception)));
48                } catch (Throwable e) {
49                    logger.warn("Fail to ExceptionFilter when called by " + RpcContext.getContext().getRemoteHost()
50                            + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName()
51                            + ", exception: " + e.getClass().getName() + ": " + e.getMessage(), e);
52                    return result;
53                }
54            }
55            return result;
56        } catch (RuntimeException e) {
57            logger.error("Got unchecked and undeclared exception which called by " + RpcContext.getContext().getRemoteHost()
58                    + ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName()
59                    + ", exception: " + e.getClass().getName() + ": " + e.getMessage(), e);
60            throw e;
61        }
62    }