捕获所有异常并返回泽西中的自定义错误

Question

@Provider
public class ExceptionMapper implements javax.ws.rs.ext.ExceptionMapper<Exception> {
    private static Logger logger = LogManager.getLogManager().getLogger(ExceptionMapper.class.getName());

    @Override
    public Response toResponse(Exception e) {
        logger.log(Level.SEVERE, e.getMessage(), e);

        return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity("Internal error").type("text/plain").build();
    }
}

public MyResult getById(@PathParam("id")) {
    if (checkAnyThing) {
        return new MyResult();
    }
    else {
        throw new WebApplicationException(Response.Status.NOT_FOUND);
    }
}

这是由映射器捕获的。现在我要写：

public Response getById(@PathParam("id") {
    if (checkAnyThing) { {
        return Response.ok().entity(new MyResult()).build();
    }
    else {
        return Response.status(Response.Status.NOT_FOUND).build();
    }
}

这是捕捉所有意外异常并返回Jersey错误（错误代码）的正确方法吗？或者还有其他（更正确的）方式吗？

Answer 1

WebApplicationException有一个GetResponse，我们可以从中获取响应。因此可以在映射器中检查WebApplicationException。也许是像

@Override
public Response toResponse(Throwable error) {
    Response response;
    if (error instanceof WebApplicationException) {
        WebApplicationException webEx = (WebApplicationException)error;
        response = webEx.getResponse();
    } else {
        response = Response.status(Response.Status.INTERNAL_SERVER_ERROR)
                .entity("Internal error").type("text/plain").build();
    }
    return response;
}

这样，抛出的WebApplicationException实例将只返回默认响应。这实际上还将处理一些其他异常，而不是由应用程序明确抛出的。WebApplicationException在其层次结构下还有一些其他由JAX-RS引发的异常，其中预定义的响应/状态代码被包装起来。

Exception                      Status code    Description
-------------------------------------------------------------------------------
BadRequestException            400            Malformed message
NotAuthorizedException         401            Authentication failure
ForbiddenException             403            Not permitted to access
NotFoundException              404            Couldn’t find resource
NotAllowedException            405            HTTP method not supported
NotAcceptableException         406            Client media type requested 
                                                            not supported
NotSupportedException          415            Client posted media type 
                                                            not supported
InternalServerErrorException   500            General server error
ServiceUnavailableException    503            Server is temporarily unavailable 
                                                            or busy

也就是说，我们可以在代码中显式地抛出任何这些异常，只是为了赋予它更多的语义价值。