- 出現的場景:
服務端通過springmvc寫了一個對外的接口,返回一個json字符串,其中該json帶有日期,格式爲yyyy-MM-dd HH:mm:ss
客戶端通過feign調用該http接口,指定返回值爲一個Dto,Dto中日期的字段爲Date類型
客戶端調用該接口後拋異常了。
報錯異常如下:
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 more
Caused 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
- 從異常信息中我們可以看出,是在AbstractJackson2HttpMessageConverter類中調用了readJavaType方法之後拋的異常
- 一步一步往下深入,我們找到了最關鍵的地方,在DeserializationContext類的_parseDate方法中,執行了df.parse(dateStr)之後拋異常了
public Date parseDate(String dateStr) throws IllegalArgumentException
{
try {
DateFormat df = getDateFormat();
// 這行代碼報錯了
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的一個反序列化的一個上下文,那麼它的DateFormat是從哪來的呢?我們再來看下getDateFormat的源碼
protected DateFormat getDateFormat()
{
if (_dateFormat != null) {
return _dateFormat;
}
DateFormat df = _config.getDateFormat();
_dateFormat = df = (DateFormat) df.clone();
return df;
}
- DateFormat又是從MapperConfig而來,我們再看下config.getDateFormat()的源碼
public final DateFormat getDateFormat() { return _base.getDateFormat(); }
- 我們知道,SpringMvc就是通過AbstractJackson2HttpMessageConverter類來整合jackson的,該類維護jackson的ObjectMapper,而ObjectMapper又是通過MapperConfig來進行配置的
- 由此可見,本異常就是因爲ObjectMapper中的DateFormat無法對yyyy-MM-dd HH:mm:ss格式的字符串進行轉換所導致的
-
異常說的值服務器返回了一個帶有日期的json,日期的形式是字符串2018-03-07 16:18:35,jackson無法將該字符串轉成一個Date對象,網上查資料,上面說的是jackson只支持以下幾種日期格式:
"yyyy-MM-dd'T'HH:mm:ss.SSSZ";
"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
-
"EEE, dd MMM yyyy HH:mm:ss zzz";
long類型的時間戳
- 去掉服務端的以下兩個配置,讓日期返回時間戳,結果就沒報錯了
#spring.jackson.date-format=yyyy-MM-dd HH:mm:ss
#spring.jackson.time-zone=Asia/Chongqing
- 由於服務端在其他的地方有可能和這裏的配置耦合了,也就是說其他地方有可能要用到的是yyyy-MM-dd HH:mm:ss這一日期格式而不是時間戳的格式,所以這個配置肯定是不能修改的。
- jackson竟然不支持yyyy-MM-dd HH:mm:ss的這種格式,肯定很不爽啦,所以下面就要開始來研究怎麼讓jackson支持這種格式了。
- 要讓jackson支持這種格式,那麼就必須修改ObjectMapper中的DateFormat,因爲在ObjectMapper中,DateFormat的默認實現類是StdDateFormat,StdDateFormat也就只兼容了我們上述所說的幾種格式
- 首先我們先使用裝飾模式來創建一個支持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; } // 主要還是裝飾這個方法 @Override public Date parse(String source) throws ParseException { Date date = null; try { // 先按我的規則來 date = format1.parse(source); } catch (Exception e) { // 不行,那就按原先的規則吧 date = dateFormat.parse(source); } return date; } // 這裏裝飾clone方法的原因是因爲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,接下來的任務就是讓ObjectMapper使用我的這個DateFormat了,在config類中定義如下(本案例基於springboot)
@Configuration
public class WebConfig {
@Autowired
private Jackson2ObjectMapperBuilder jackson2ObjectMapperBuilder;
@Bean
public MappingJackson2HttpMessageConverter MappingJsonpHttpMessageConverter() {
ObjectMapper mapper = jackson2ObjectMapperBuilder.build();
// ObjectMapper爲了保障線程安全性,裏面的配置類都是一個不可變的對象
// 所以這裏的setDateFormat的內部原理其實是創建了一個新的配置類
DateFormat dateFormat = mapper.getDateFormat();
mapper.setDateFormat(new MyDateFormat(dateFormat));
MappingJackson2HttpMessageConverter mappingJsonpHttpMessageConverter = new MappingJackson2HttpMessageConverter(
mapper);
return mappingJsonpHttpMessageConverter;
}
}
- 配置了上述代碼之後,問題成功解決。
3、爲什麼往spring容器中注入MappingJackson2HttpMessageConverter,springMvc就會用這個Converter呢?
- 查看springboot的源代碼如下:
@Configuration
class 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);
}
}
- 默認配置爲,當spring容器中沒有MappingJackson2HttpMessageConverter這個實例的時候纔會被創建
- springboot的思想是約定優於配置,也就是說,springboot默認幫我們配好了spring mvc的Converter,如果我們沒有自定義Converter的話,那麼框架就會幫我們創建一個,如果我們有自定義的話,那麼springboot就直接使用我們所註冊的bean進行綁定