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The purpose of this article is to share with you about how to report errors in Springcloud feign date type parameters. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

Feign date type parameter error Date type parameter error

Passing the Date type parameter in the Spring cloud feign interface is an error or error message.

Scene:

The client passes a parameter of new Date (), and there is a time difference between the parameters accepted by the server and the client.

Client prints formatted new Date ():

2018-05-11 10:23:36

The parameters received by the server are:

2018-05-12 00:23:36

We can see from the source code started by Feign that Feign uses the SpringEncoder class to implement encode and decode:

@ Bean @ ConditionalOnMissingBean public Decoder feignDecoder () {return new ResponseEntityDecoder (new SpringDecoder (this.messageConverters));} @ Bean @ ConditionalOnMissingBean public Encoder feignEncoder () {return new SpringEncoder (this.messageConverters);}

SpringEncoder's HttpMessageConverters uses the Jackson default template, which comes from the base class WebMvcConfigurationSupport.java:

Protected final List > (); configureMessageConverters (this.messageConverters); if (this.messageConverters.isEmpty ()) {addDefaultHttpMessageConverters (this.messageConverters);} extendMessageConverters (this.messageConverters);} return this.messageConverters;}

WebMvcConfigurationSupport.java ends up using the default MappingJackson2HttpMessageConverter generated by ObjectMapper.

So far, we can see that the problem is not the problem of Feign, but the problem of Jackson conversion parameters in Spring MVC used in Feign implementation. The default TimeZone is not East eighth Zone, but UTC.

/ * * Override the default {@ link TimeZone} to use for formatting. * Default value used is UTC (NOT local timezone). * @ since 4.1.5 * / public Jackson2ObjectMapperBuilder timeZone (TimeZone timeZone) {this.timeZone = timeZone; return this;}

This problem can be solved by adding comments to interfaces or fields in Spring MVC, but it is not possible to add annotations to interfaces requested by GET in Feign. Debug found that when Spring MVC was dealing with Date, it called sun.reflect.ConstructorAccessor#newInstance (Object [] var1), which added 14 hours. The specific implementation does not see the source code, we will study it later. It should be noted that adding JsonFormat annotations does not work for the Feign interface, but Spring MVC is OK.

OK, back to the point. The best way to solve this problem is to customize ObjectMapper. Even if annotations can solve the problem, it is still recommended to use custom ObjectMapper, because it is too cumbersome to add annotations to each of a large number of interfaces.

@ Bean @ Primary public ObjectMapper objectMapper () {return Jackson2ObjectMapperBuilder.json () .serializationInclusion (JsonInclude.Include.NON_NULL) .timezone (TimeZone.getTimeZone ("Asia/Shanghai")) .build ();}

The ObjectMapper annotated in this way has a time zone.

LocalDate type error

Error details:

Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Can not construct instance of java.time.LocalDate: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of java.time.LocalDate: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?)

At [Source: java.io.PushbackInputStream@3ce2b1e2; line: 1, column: 44] (through reference chain: com.chunrun.user.param.UserParams ["localDate"])

This is because LocalDate does not provide a default constructor, and Jackson does not support the characteristics of Java8. At this point, all you need to do is add dependency and add a line of code to ObjectMapper:

Com.fasterxml.jackson.datatype jackson-datatype-jsr310 2.4.0 @ Bean @ Primary public ObjectMapper objectMapper () {return Jackson2ObjectMapperBuilder.json () .serializationInclusion (JsonInclude.Include.NON_NULL) .serializationDisable (SerializationFeature.WRITE_DATES_AS_TIMESTAMPS) .timezone (TimeZone.getTimeZone ("Asia/Shanghai")). Modules (new JSR310Module ()) .build () }

The above configuration is also required by the caller.

The problem of transmitting parameters in feign and the pit of time difference in transmitting Date type parameters

The call to feign is as follows:

List getLeftSeatCountOfDays (@ RequestParam ("configType") Integer configType, @ RequestParam ("courseId") Long courseId, @ RequestParam ("startDateFrom") Date startDateFrom, @ RequestParam ("startDateTo") Date startDateTo, @ RequestParam ("level") Integer level)

We use two parameters of type date to pass parameters, and the result is:

The time we passed in is:

However, the time received by the server is:

Oh, my God, there is a 14-hour jet lag that we are not familiar with, not the 8 hours we are familiar with. Feign is really a sinkhole. This is caused by the time difference of the Date type parameter passed by SpringCloud Feign.

Note: use date type to pass parameters. If you pass parameters with objects in body, there will be no jet lag.

Let's talk about two solutions

When sending a time type, send it directly with String (recommended)

Feign client implements FeignFormatterRegistrar interface custom DateFormatRegister

@ Component public class DateFormatRegister implements FeignFormatterRegistrar {public DateFormatRegister () {} @ Override public void registerFormatters (FormatterRegistry registry) {registry.addConverter (Date.class, String.class, new Date2StringConverter ());} private class Date2StringConverter implements Converter {@ Override public String convert (Date source) {SimpleDateFormat sdf = new SimpleDateFormat ("yyyy-MM-dd HH:mm:ss") Return sdf.format (source);}

Server-side implementation:

@ Configuration public class WebConfigBeans {@ Autowired private RequestMappingHandlerAdapter handlerAdapter; / * add string to date function * / @ PostConstruct public void initEditableValidation () {ConfigurableWebBindingInitializer initializer = (ConfigurableWebBindingInitializer) handlerAdapter .getWebBindingInitiali zer () If (initializer.getConversionService ()! = null) {GenericConversionService genericConversionService = (GenericConversionService) initializer.getConversionService (); genericConversionService.addConverter (String.class, Date.class, new String2DateConverter ();}

The second is troublesome, but once and for all, the elegance of the code is better than the first. But personally, the first one is recommended.

Feign uses @ DateTimeFormat annotated pit @ NotNull @ MyFuture @ DateTimeFormat (pattern = "yyyy-MM-dd") private Date appointDate; / / scheduled pre-class date when passing parameters.

For example, in this field, the @ DateTimeFormat annotation is used on the server, so that the springMVC phone supports direct string 2018-03-03 automatic conversion. However, if you are calling with client, there is no error, no error. Therefore, when using it, we must pay attention to it.

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