com.fasterxml.jackson.databind.exc.MismatchedInputException：意外令牌

Question

我正在尝试发布一个用户组：

public UserGroup createUserGroup(UserGroup userGroup) {
    ResponseEntity<UserGroup> userGroupResponseEntity = oauthRestTemplate
            .postForEntity(GROUPS_ENDPOINT, userGroup, UserGroup.class);
    return userGroupResponseEntity.getBody();
}

由于我正在使用@RepositoryRestResource，因此必须配置对象映射器：

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.registerModule(new Jackson2HalModule());
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);

MappingJackson2HttpMessageConverter messageConverter = new MappingJackson2HttpMessageConverter();
messageConverter.setObjectMapper(objectMapper);
messageConverter.setSupportedMediaTypes(Collections.singletonList(MediaTypes.HAL_JSON));

this.oauthRestTemplate.setMessageConverters(Collections.singletonList(messageConverter));

但是，从上面运行POST会抛出我

Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: Unexpected token (START_OBJECT), expected VALUE_STRING: Expected array or string.
 at [Source: (org.apache.catalina.connector.CoyoteInputStream); line: 1, column: 87] (through reference chain: mahlzeit.api.hibernate.model.UserGroup["voteUntil"])
    at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:63) ~[jackson-databind-2.9.4.jar:2.9.4]
    at com.fasterxml.jackson.databind.DeserializationContext.wrongTokenException(DeserializationContext.java:1507) ~[jackson-databind-2.9.4.jar:2.9.4]
    at com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer.deserialize(LocalDateTimeDeserializer.java:138) ~[jackson-datatype-jsr310-2.9.2.jar:2.9.2]
    at com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer.deserialize(LocalDateTimeDeserializer.java:39) ~[jackson-datatype-jsr310-2.9.2.jar:2.9.2]
    at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:127) ~[jackson-databind-2.9.4.jar:2.9.4]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:369) ~[jackson-databind-2.9.4.jar:2.9.4]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:159) ~[jackson-databind-2.9.4.jar:2.9.4]
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4001) ~[jackson-databind-2.9.4.jar:2.9.4]
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3072) ~[jackson-databind-2.9.4.jar:2.9.4]
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:235) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    ... 93 common frames omitted

2018-04-02 15:12:52.788 DEBUG 1811 --- [nio-8081-exec-3] o.s.s.w.header.writers.HstsHeaderWriter  : Not injecting HSTS header since it did not match the requestMatcher org.springframework.security.web.header.writers.HstsHeaderWriter$SecureRequestMatcher@24f17053
2018-04-02 15:12:52.789 DEBUG 1811 --- [nio-8081-exec-3] o.s.s.w.a.ExceptionTranslationFilter     : Chain processed normally
2018-04-02 15:12:52.789 DEBUG 1811 --- [           main] o.s.s.oauth2.client.OAuth2RestTemplate   : POST request for "http://localhost:8081/groups" resulted in 400 (null); invoking error handler
2018-04-02 15:12:52.789 DEBUG 1811 --- [nio-8081-exec-3] s.s.w.c.SecurityContextPersistenceFilter : SecurityContextHolder now cleared, as request processing completed
org.springframework.web.client.HttpClientErrorException: 400 null
    at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:94)
    at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:79)
    at org.springframework.security.oauth2.client.http.OAuth2ErrorHandler.handleError(OAuth2ErrorHandler.java:172)
    at org.springframework.web.client.ResponseErrorHandler.handleError(ResponseErrorHandler.java:63)
    at org.springframework.web.client.RestTemplate.handleResponse(RestTemplate.java:777)
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:730)
    at org.springframework.security.oauth2.client.OAuth2RestTemplate.doExecute(OAuth2RestTemplate.java:128)
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:686)
    at org.springframework.web.client.RestTemplate.postForEntity(RestTemplate.java:468)

我不明白为什么！

Answer 1

对于遇到这种情况的任何人-这就是为什么如果您不小心或记得事先配置的100万件事，Spring有时会变得如此令人沮丧的原因。

因此，如果您像我一样，并且习惯于application-test.properties配置某些事物，我们可以这样说：

# Used to enable ISO format for time data
spring.jackson.serialization.WRITE_DATES_AS_TIMESTAMPS = false

但是已经忘记了这一点，那么您可能需要牢记，就像我一样，自定义设置属性就将被忽略ObjectMapper，以便使用hal+jsonSpring Data REST端点的输出。因此，您可能需要设置：

objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
objectMapper.registerModule(new JavaTimeModule());