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自定义jackson解析时间格式yyy-MM-dd HH:mm:ss
阅读量:7211 次
发布时间:2019-06-29

本文共 14740 字,大约阅读时间需要 49 分钟。

  hot3.png

1、问题排查

  1. 出现的场景:

    • 服务端通过springmvc写了一个对外的接口,返回一个json字符串,其中该json带有日期,格式为yyyy-MM-dd HH:mm:ss

    • 客户端通过feign调用该http接口,指定返回值为一个Dto,Dto中日期的字段为Date类型

    • 客户端调用该接口后抛异常了。

  2. 异常如下:

    feign.codec.DecodeException: JSON parse error: Can not deserialize value of type java.util.Date from String "2018-03-07 16:18:35": not a valid representation (error: Failed to parse Date value '2018-03-07 16:18:35': Can not parse date "2018-03-07 16:18:35Z": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSS'Z'', parsing fails (leniency? null)); nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Can not deserialize value of type java.util.Date from String "2018-03-07 16:18:35": not a valid representation (error: Failed to parse Date value '2018-03-07 16:18:35': Can not parse date "2018-03-07 16:18:35Z": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSS'Z'', parsing fails (leniency? null)) at [Source: java.io.PushbackInputStream@4615bc00; line: 1, column: 696] (through reference chain: com.RestfulDataBean["data"]->java.util.ArrayList[0]->com.entity.XxxDto["createTime"])	at feign.SynchronousMethodHandler.decode(SynchronousMethodHandler.java:169)	at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:133)	at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:76)	at feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:103)	at com.sun.proxy.$Proxy138.queryMonitorByTime(Unknown Source)	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:738)	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)	at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282)	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:673)	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)	at java.lang.reflect.Method.invoke(Method.java:498)	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)	at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)	at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)	at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)Caused by: org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Can not deserialize value of type java.util.Date from String "2018-03-07 16:18:35": not a valid representation (error: Failed to parse Date value '2018-03-07 16:18:35': Can not parse date "2018-03-07 16:18:35Z": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSS'Z'', parsing fails (leniency? null)); nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Can not deserialize value of type java.util.Date from String "2018-03-07 16:18:35": not a valid representation (error: Failed to parse Date value '2018-03-07 16:18:35': Can not parse date "2018-03-07 16:18:35Z": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSS'Z'', parsing fails (leniency? null)) at [Source: java.io.PushbackInputStream@4615bc00; line: 1, column: 696] (through reference chain: com.RestfulDataBean["data"]->java.util.ArrayList[0]->com.XxxDto["createTime"])	at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:238)	at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:223)	at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:96)	at org.springframework.cloud.netflix.feign.support.SpringDecoder.decode(SpringDecoder.java:59)	at org.springframework.cloud.netflix.feign.support.ResponseEntityDecoder.decode(ResponseEntityDecoder.java:47)	at feign.SynchronousMethodHandler.decode(SynchronousMethodHandler.java:165)	... 45 moreCaused by: com.fasterxml.jackson.databind.exc.InvalidFormatException: Can not deserialize value of type java.util.Date from String "2018-03-07 16:18:35": not a valid representation (error: Failed to parse Date value '2018-03-07 16:18:35': Can not parse date "2018-03-07 16:18:35Z": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSS'Z'', parsing fails (leniency? null)) at [Source: java.io.PushbackInputStream@4615bc00; line: 1, column: 696] (through reference chain: com.RestfulDataBean["data"]->java.util.ArrayList[0]->com.XxxDto["createTime"])	at com.fasterxml.jackson.databind.exc.InvalidFormatException.from(InvalidFormatException.java:74)	at com.fasterxml.jackson.databind.DeserializationContext.weirdStringException(DeserializationContext.java:1410)	at com.fasterxml.jackson.databind.DeserializationContext.handleWeirdStringValue(DeserializationContext.java:926)	at com.fasterxml.jackson.databind.deser.std.StdDeserializer._parseDate(StdDeserializer.java:819)	at com.fasterxml.jackson.databind.deser.std.StdDeserializer._parseDate(StdDeserializer.java:788)	at com.fasterxml.jackson.databind.deser.std.DateDeserializers$DateBasedDeserializer._parseDate(DateDeserializers.java:172)	at com.fasterxml.jackson.databind.deser.std.DateDeserializers$DateDeserializer.deserialize(DateDeserializers.java:259)	at com.fasterxml.jackson.databind.deser.std.DateDeserializers$DateDeserializer.deserialize(DateDeserializers.java:242)	at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:504)	at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:104)	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:357)	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:148)	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:287)	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:259)	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:26)	at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:504)	at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:104)	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:357)	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:148)	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3814)	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2938)	at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:235)	... 50 more
    • 从异常信息中我们可以看出,是在AbstractJackson2HttpMessageConverter类中调用了readJavaType方法之后抛的异常

    • 一步一步往下深入,我们找到了最关键的地方,在DeserializationContext类的_parseDate方法中,执行了df.parse(dateStr)之后抛异常了

    • public Date parseDate(String dateStr) throws IllegalArgumentException{    try {        DateFormat df = getDateFormat();        // 这行代码报错了        return df.parse(dateStr);    } catch (ParseException e) {        throw new IllegalArgumentException(String.format(                "Failed to parse Date value '%s': %s", dateStr, e.getMessage()));    }}

      DeserializationContext是jackson的一个反序列化的一个上下文,那么它的DateFormat是从哪来的呢?我们再来看下getDateFormat的源码

    • protected DateFormat getDateFormat(){    if (_dateFormat != null) {        return _dateFormat;    }    DateFormat df = _config.getDateFormat();    _dateFormat = df = (DateFormat) df.clone();    return df;}

      DateFormat又是从MapperConfig而来,我们再看下config.getDateFormat()的源码

    • public final DateFormat getDateFormat() { return _base.getDateFormat(); }

      我们知道,SpringMvc就是通过AbstractJackson2HttpMessageConverter类来整合jackson的,该类维护jackson的ObjectMapper,而ObjectMapper又是通过MapperConfig来进行配置的

    • 由此可见,本异常就是因为ObjectMapper中的DateFormat无法对yyyy-MM-dd HH:mm:ss格式的字符串进行转换所导致的

2、问题处理

  • 异常说的值服务器返回了一个带有日期的json,日期的形式是字符串2018-03-07 16:18:35,jackson无法将该字符串转成一个Date对象,网上查资料,上面说的是jackson只支持以下几种日期格式:

    • "yyyy-MM-dd'T'HH:mm:ss.SSSZ";

    • "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";

    • "yyyy-MM-dd";

    • "EEE, dd MMM yyyy HH:mm:ss zzz";

    • long类型的时间戳

  • 去掉服务端的以下两个配置,让日期返回时间戳,结果就没报错了

  • #spring.jackson.date-format=yyyy-MM-dd HH:mm:ss#spring.jackson.time-zone=Asia/Chongqing

     

  • 由于服务端在其他的地方有可能和这里的配置耦合了,也就是说其他地方有可能要用到的是yyyy-MM-dd HH:mm:ss这一日期格式而不是时间戳的格式,所以这个配置肯定是不能修改的。

  • jackson竟然不支持yyyy-MM-dd HH:mm:ss的这种格式,肯定很不爽啦,所以下面就要开始来研究怎么让jackson支持这种格式了。

  • 要让jackson支持这种格式,那么就必须修改ObjectMapper中的DateFormat,因为在ObjectMapper中,DateFormat的默认实现类是StdDateFormat,StdDateFormat也就只兼容了我们上述所说的几种格式

  • 首先我们先使用装饰模式来创建一个支持yyyy-MM-dd HH:mm:ss格式的DateFormat如下

  • import java.text.DateFormat;import java.text.FieldPosition;import java.text.ParseException;import java.text.ParsePosition;import java.text.SimpleDateFormat;import java.util.Date; public class MyDateFormat extends DateFormat { 	private DateFormat dateFormat; 	private SimpleDateFormat format1 = new SimpleDateFormat("yyy-MM-dd HH:mm:ss"); 	public MyDateFormat(DateFormat dateFormat) {		this.dateFormat = dateFormat;	} 	@Override	public StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition) {		return dateFormat.format(date, toAppendTo, fieldPosition);	} 	@Override	public Date parse(String source, ParsePosition pos) { 		Date date = null; 		try { 			date = format1.parse(source, pos);		} catch (Exception e) { 			date = dateFormat.parse(source, pos);		} 		return date;	} 	// 主要还是装饰这个方法	@Override	public Date parse(String source) throws ParseException { 		Date date = null; 		try {						// 先按我的规则来			date = format1.parse(source);		} catch (Exception e) { 			// 不行,那就按原先的规则吧			date = dateFormat.parse(source);		} 		return date;	} 	// 这里装饰clone方法的原因是因为clone方法在jackson中也有用到	@Override	public Object clone() {		Object format = dateFormat.clone();		return new MyDateFormat((DateFormat) format);	}}

    DateFormat有了,接下来的任务就是让ObjectMapper使用我的这个DateFormat了,在config类中定义如下(本案例基于springboot)

  • @Configurationpublic class WebConfig { 	@Autowired	private Jackson2ObjectMapperBuilder jackson2ObjectMapperBuilder;		@Bean	public MappingJackson2HttpMessageConverter MappingJsonpHttpMessageConverter() { 		ObjectMapper mapper = jackson2ObjectMapperBuilder.build(); 		// ObjectMapper为了保障线程安全性,里面的配置类都是一个不可变的对象		// 所以这里的setDateFormat的内部原理其实是创建了一个新的配置类		DateFormat dateFormat = mapper.getDateFormat();		mapper.setDateFormat(new MyDateFormat(dateFormat)); 		MappingJackson2HttpMessageConverter mappingJsonpHttpMessageConverter = new MappingJackson2HttpMessageConverter(				mapper);		return mappingJsonpHttpMessageConverter;	}}

     

  • 配置了上述代码之后,问题成功解决。

3、为什么往spring容器中注入MappingJackson2HttpMessageConverter,springMvc就会用这个Converter呢?

  • 查看springboot的源代码如下:

    @Configurationclass JacksonHttpMessageConvertersConfiguration { 	@Configuration	@ConditionalOnClass(ObjectMapper.class)	@ConditionalOnBean(ObjectMapper.class)	@ConditionalOnProperty(name = HttpMessageConvertersAutoConfiguration.PREFERRED_MAPPER_PROPERTY, havingValue = "jackson", matchIfMissing = true)	protected static class MappingJackson2HttpMessageConverterConfiguration { 		@Bean		@ConditionalOnMissingBean(value = MappingJackson2HttpMessageConverter.class, ignoredType = {				"org.springframework.hateoas.mvc.TypeConstrainedMappingJackson2HttpMessageConverter",				"org.springframework.data.rest.webmvc.alps.AlpsJsonHttpMessageConverter" })		public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter(				ObjectMapper objectMapper) {			return new MappingJackson2HttpMessageConverter(objectMapper);		} }

     

  • 默认配置为,当spring容器中没有MappingJackson2HttpMessageConverter这个实例的时候才会被创建

  • springboot的思想是约定优于配置,也就是说,springboot默认帮我们配好了spring mvc的Converter,如果我们没有自定义Converter的话,那么框架就会帮我们创建一个,如果我们有自定义的话,那么springboot就直接使用我们所注册的bean进行绑定

  • 以上摘自https://blog.csdn.net/qq906627950/article/details/79503801

  • 补充:

  • 使用JsonFormat注解的时候需要加上时区

    • import com.fasterxml.jackson.annotation.JsonFormat;@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",timezone = "GMT+8")

      中国的时区 东8区 ,timezone="GMT+8" 是必须加上去的不然转换后的时间和数据库里的时间是不一样的。

  • 补充摘自 https://blog.csdn.net/wxlhdm/article/details/45073393

 

转载于:https://my.oschina.net/xpx/blog/1924695

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