将列表序列化为 json 时出现异常 [重复]

Question

我在将对象列表序列化为 JSON (Jackson) 时遇到问题。我的对象包含带有德语变音符号的字符串（例如 ä、ö、ü、ß）。当我将包含这些对象的列表发送到我的服务器时，我得到一个 JsonMappingException: Invalid UTF-8 middle byte。我 100% 的问题出在客户端，因为当我通过邮递员发送 JSON 字符串时，它工作得很好。

public static ResponseEntity<?> exchange(String servicePath, HttpMethod method, Class returnClass, List<? extends BaseObject> objectList, Object... uriVariableValues) throws JsonProcessingException, UnsupportedEncodingException
{
    RestTemplate template = new RestTemplate();
    template.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
    template.getMessageConverters().add(new StringHttpMessageConverter(Charset.forName("UTF-8")));

    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.APPLICATION_JSON);

    String url = ConfigHandler.getServicePath(servicePath);
    UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(ConfigHandler.getStringProperty("baseUrl"));
    URI uri = builder.path(url).buildAndExpand(uriVariableValues).toUri();
    byte[] bytes = Utils.getJacksonObjectMapper().writeValueAsBytes(objectList);

    //String urlParameters = new String(Utils.getJacksonObjectMapper().writeValueAsString(objectList).getBytes("UTF-8"));
    String urlParameters = new String(bytes, "UTF-8");
    //urlParameters = urlParameters.replaceAll("ß", "HURZ");
    System.out.println("WebUtils.exchange - JSON: "+urlParameters);

    HttpEntity<String> entity = new HttpEntity<>(urlParameters, headers);

    return template.exchange(uri, method, entity, returnClass);
}

public static ObjectMapper getJacksonObjectMapper()
{
    ObjectMapper mapper = new ObjectMapper()
            .registerModule(new ParameterNamesModule())
            .registerModule(new Jdk8Module()).registerModule(new JavaTimeModule());
    mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
    mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

    return mapper;
}

有问题的 JSON 字符串如下{"objectType":"TRANSLATION_PARAMETER","changed":true,"type":"java.lang.String","locale":"de_DE","value":"Schließen","section":null,"prettyId":"","active":true,"createdDate":"2017-10-01T13:35:52.6","name":"General.close","id":0,"description":" "}

Answer 1

如果将来有人偶然发现这个问题，解决方案是在 HttpHeaders 中添加更多内容：

HttpHeaders headers = new HttpHeaders();
MediaType mediaType = new MediaType("application", "json", Charset.forName("UTF-8"));
headers.setContentType(mediaType);
headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
headers.setAcceptCharset(Arrays.asList(Charset.forName("UTF-8")));

Answer 2

在您的客户端设置正确的编码：

updateRequest.setHeader("Content-Type", "application/json;charset=UTF-8");
StringEntity entity= new StringEntity(json, "UTF-8");
updateRequest.setEntity(entity);