当杰克逊反序列化失败时，泽西岛异常映射器不起作用 [英] Jersey Exception mappers not working when jackson deserialization fails

问题描述

我在 REST API 中使用 Jersey 2.10 和 Jackson 序列化/反序列化功能.

I am using Jersey 2.10 with Jackson serialization/deserialization feature in my REST API.

我的想法是让我的 REST API 始终返回标准的 JSON 错误响应.为此，我有 ExceptionMapper 类，可以为 Jersey 应用程序中抛出的任何异常构建正确的 json 错误响应.我还有一个 jsp，它生成相同类型的 JSON 响应，我在 web.xml 中将其注册为错误页面，该页面涵盖了加载 Jersey 之前可能出现的所有错误.

My idea is to make my REST API to always return a standard JSON error response. For that I have ExceptionMapper classes that build proper json error responses for any exception being thrown in the Jersey application. I also have a jsp which produces the same kind of JSON response, which I registered as error-page in the web.xml that covers all the errors that could come before Jersey being loaded.

但是在一种情况下，我的异常映射器和我的 json 生成 jsp 都不起作用，那就是将格式错误的 json 发送到 POST REST 端点时，该端点只返回以下消息:

But there is one case in which neither my Exception mappers nor my json producing jsp are working, that is when sending a bad formed json to a POST REST endpoint which just returns the following message:

HTTP/1.1 400 Bad Request
Server: Apache-Coyote/1.1
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET, POST, DELETE, PUT
Content-Type: text/plain
Content-Length: 210
Date: Tue, 24 Jun 2014 22:14:11 GMT
Connection: close

Can not deserialize instance of com.example.rest.User[] out of START_OBJECT token
 at [Source: org.glassfish.jersey.message.internal.EntityInputStream@1dcccac; line: 1, column: 1]

我怎样才能让 Jersey 返回我的自定义错误响应而不是这个?

How can I make Jersey to return my custom error response instead of this?

更新:

根据@Lucasz 的回答，我做了更多的研究，发现在包 com.fasterxml.jackson.jaxrs.base (https://github.com/FasterXML/jackson-jaxrs-provider/tree/master/base/src/main/java/com/fasterxml/jackson/jaxrs/base) JsonMappingExceptionMapper 和 JsonParseExceptionMapper 似乎影响了我的自定义映射器.

Based on the answer by @Lucasz, I did more research and found that there are two Exception mappers defined inside the package com.fasterxml.jackson.jaxrs.base (https://github.com/FasterXML/jackson-jaxrs-providers/tree/master/base/src/main/java/com/fasterxml/jackson/jaxrs/base) JsonMappingExceptionMapper and JsonParseExceptionMapper that seem to be shadowing my custom mappers.

如何取消注册这些映射器?

How can I unregister those mappers?

这是我目前注册映射器的方式:

This is how I am currently registering the mappers:

@ApplicationPath("/")
public class MyApp extends ResourceConfig{
    public SyntheticAPIApp() {
        packages("com.example.resource", "com.example.mapper");
        register(org.glassfish.jersey.jackson.JacksonFeature.class);
    }
}

推荐答案

我使用如下异常映射器对其进行了测试:

I tested it with an exception mapper like below:

import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;
import javax.ws.rs.ext.ExceptionMapper;
import javax.ws.rs.ext.Provider;

import com.fasterxml.jackson.core.JsonProcessingException;

@Provider
public class JsonProcessingExceptionMapper implements ExceptionMapper<JsonProcessingException>{

        public static class Error {
            public String key;
            public String message;
        }

        @Override
        public Response toResponse(JsonProcessingException exception) {
            Error error = new Error();
            error.key = "bad-json";
            error.message = exception.getMessage();
            return Response.status(Status.BAD_REQUEST).entity(error).build();
        }
}

它奏效了.

更新:将 JsonParseException 更改为 JsonProcessingException(更通用)

Update: changed JsonParseException to JsonProcessingException (more general)

更新 2:为了避免注册不需要的映射器替换

Update2: In order to avoid registering the unwanted mappers replace

register(org.glassfish.jersey.jackson.JacksonFeature.class);

与

register(com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider.class);

查看JacksonFeature 你就会明白发生了什么.

Look at the source code of JacksonFeature and you'll understand what's happening.

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