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做房源网站,高新区网站建设,做旅行网站多少钱,优秀网页设计作品分析ppt为什么80%的码农都做不了架构师#xff1f; 1、问题排查 出现的场景#xff1a; 服务端通过springmvc写了一个对外的接口#xff0c;返回一个json字符串#xff0c;其中该json带有日期#xff0c;格式为yyyy-MM-dd HH:mm:ss 客户端通过feign调用该http接口… 为什么80%的码农都做不了架构师    1、问题排查 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DtoDto中日期的字段为Date类型 客户端调用该接口后抛异常了。 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-ddTHH:mm:ss.SSSZ, 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-ddTHH:mm:ss.SSSZ, parsing fails (leniency? null))at Source: java.io.PushbackInputStream4615bc00; line: 1, column: 696at 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-ddTHH:mm:ss.SSSZ, 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-ddTHH:mm:ss.SSSZ, parsing fails (leniency? null))at Source: java.io.PushbackInputStream4615bc00; line: 1, column: 696at 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-ddTHH:mm:ss.SSSZ, parsing fails (leniency? null))at Source: java.io.PushbackInputStream4615bc00; line: 1, column: 696at 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 16:18:35jackson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-ddTHH:mm:ss.SSSZ yyyy-MM-ddTHH:mm:ss.SSSZ 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-formatyyyy-MM-dd HH:mm:ss #spring.jackson.time-zoneAsia/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StdDateFormatStdDateFormat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;}Overridepublic StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition) {return dateFormat.format(date, toAppendTo, fieldPosition);}Overridepublic 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Overridepublic 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Overridepublic 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 Configuration public class WebConfig {Autowiredprivate Jackson2ObjectMapperBuilder jackson2ObjectMapperBuilder;Beanpublic 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MappingJackson2HttpMessageConverterspringMvc就会用这个Converter呢 查看springboot的源代码如下 Configuration class JacksonHttpMessageConvertersConfiguration {ConfigurationConditionalOnClass(ObjectMapper.class)ConditionalOnBean(ObjectMapper.class)ConditionalOnProperty(name HttpMessageConvertersAutoConfiguration.PREFERRED_MAPPER_PROPERTY, havingValue jackson, matchIfMissing true)protected static class MappingJackson2HttpMessageConverterConfiguration {BeanConditionalOnMissingBean(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 GMT8) 中国的时区 东8区 timezoneGMT8 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