java 捕获所有异常并返回 Jersey 中的自定义错误
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Catch all Exceptions and also return custom Errors in Jersey
提问by Dominic
I want to catch all unexpected Exceptions in a jersey rest service. Therefore i wrote an ExceptionMapper:
我想在球衣休息服务中捕获所有意外的异常。因此我写了一个ExceptionMapper：
@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();
}
}
The mapper catches really all exceptions. Therefore i can't write:
映射器确实捕获了所有异常。因此我不能写：
public MyResult getById(@PathParam("id")) {
if (checkAnyThing) {
return new MyResult();
}
else {
throw new WebApplicationException(Response.Status.NOT_FOUND);
}
}
This is catched by the Mapper. Now i have to write:
这是由 Mapper 捕获的。现在我必须写：
public Response getById(@PathParam("id") {
if (checkAnyThing) { {
return Response.ok().entity(new MyResult()).build();
}
else {
return Response.status(Response.Status.NOT_FOUND).build();
}
}
Is this the correct way to catch all unexpected exceptions and also return errors (error codes) in jersey? Or is there any other (more correct) way?
这是捕获所有意外异常并在球衣中返回错误（错误代码）的正确方法吗？或者还有其他（更正确的）方法吗？
回答by Paul Samsotha
WebApplicationExceptionhas a getResponsefrom which we can get the Response. So you can check for a WebApplicationExceptionin your mapper. Maybe something like
WebApplicationException有一个getResponse我们可以从中得到Response. 因此，您可以WebApplicationException在映射器中检查 a 。也许像
@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;
}
That way an instance of WebApplicationExceptionthrown will just return the default response. This will actually handle some other exceptions also, not thrown explictly by your application. WebApplicationExceptionhas a few other exception under its hierarchy that are thrown by JAX-RS, for which predefined response/status codes are wrapped.
这样， throw 的实例WebApplicationException只会返回默认响应。这实际上也将处理一些其他异常，而不是由您的应用程序明确抛出。WebApplicationException在其层次结构下还有一些其他异常，这些异常由 JAX-RS 抛出，为其包装了预定义的响应/状态代码。
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
That being said, we could explicitly throw any of these exceptions in our code, just to give it more semantic value.
话虽如此，我们可以在我们的代码中明确抛出任何这些异常，只是为了赋予它更多的语义价值。
Generally speaking though, the example above may be unnecessary, unless you want to alter the response message/status code, as one can from the table above, the hierarchy of exceptions already have some general mapping. And in most cases, unexpected exceptions will already be mapped to InternalServerErrorException
不过一般来说，上面的例子可能是不必要的，除非你想改变响应消息/状态代码，正如从上表中可以看出的，异常的层次结构已经有了一些通用的映射。并且在大多数情况下，意外的异常已经被映射到InternalServerErrorException
