如何更改异常处理程序中的内容类型

Question

@RequestMapping(value = "/meta/{itemId}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
@ResponseBody
public MetaInformation getMetaInformation(@PathVariable int itemId) {
    return myService.getMetaInformation(itemId);
}

@ExceptionHandler(IllegalArgumentException.class)
@ResponseStatus(value = HttpStatus.BAD_REQUEST)
@ResponseBody
public String handleIllegalArgumentException(IllegalArgumentException ex) {
    return ExceptionUtils.getStackTrace(ex);
}

<mvc:annotation-driven>
    <mvc:message-converters>
        <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter" />
        <bean class="org.springframework.http.converter.StringHttpMessageConverter" />
    </mvc:message-converters>
</mvc:annotation-driven>

为了使图片更完整（也更复杂），假设我还有以下处理程序：

@RequestMapping(value = "/version", method = RequestMethod.GET)
@ResponseBody
public String getApplicationVersion() {
    return "1.0.12";
}

此处理程序允许返回字符串由MappingJackson2HttpMessageConverter和StringhtTpMessageConverter序列化，具体取决于客户端传递的Accept-Type。返回类型和值应如下：

+----+---------------------+-----------------------+------------------+-------------------------------------+
| NN | URL                 | Accept-type           | Content-type     | Message converter                   |
|    |                     | request header        | response header  |                                     |
+----+---------------------+-----------------------+------------------+-------------------------------------+
| 1. | /version            | text/html; */*        | text/plain       | StringHttpMessageConverter          |
| 2. | /version            | application/json; */* | application/json | MappingJackson2HttpMessageConverter |
| 3. | /meta/1             | text/html; */*        | application/json | MappingJackson2HttpMessageConverter |
| 4. | /meta/1             | application/json; */* | application/json | MappingJackson2HttpMessageConverter |
| 5. | /meta/0 (exception) | text/html; */*        | text/plain       | StringHttpMessageConverter          |
| 6. | /meta/0 (exception) | application/json; */* | text/plain       | StringHttpMessageConverter          |
+----+---------------------+-----------------------+------------------+-------------------------------------+

Answer 1

我认为从getMetainFormation的@requestmapping中删除produces=mediatype.application_json_value会得到所需的结果。

响应类型将根据Accept头中的content-type值进行协商。

编辑

@ExceptionHandler(Exception.class)
public ResponseEntity<String> handleIllegalArgumentException(Exception ex) {
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.TEXT_PLAIN);
    return new ResponseEntity<String>(ex.getMessage(), headers, HttpStatus.BAD_REQUEST);
}