Spring Mvc使用Jackson进行json转对象时，遇到的字符串转日期的异常处理（Can not deserialize value of type Date from String）

其他 2018-07-25 14:09:53 阅读次数: 0

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。

  • 报错异常如下：

    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 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

  • 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）

    @Configuration
public 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：

    @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

猜你喜欢

转载自blog.csdn.net/qq906627950/article/details/79503801
今日推荐
面壁智能发布 Eurux-8x22B 开源大模型 —— 堪称「理科状元」
开源日报 | 谷歌扶持鸿蒙上位；开源Rabbit R1；Docker加持的安卓手机；微软的焦虑和野心；海尔电器把开放平台关了
中国码农的“35岁魔咒”
蘭雅 CorelDRAW 插件 2024.5.1 国际劳动节版，免费下载
Arc Browser for Windows 1.0 正式 GA
90后程序员开发视频搬运软件、不到一年获利超 700 万，结局很刑！
周排行
【转】spring中对控制反转和依赖注入的理解
tms webcore 安装和使用
java程序员进阶相关书籍
SpringMVC接受请求参数、
如何保存训练好的机器学习模型
MyEclipse、Eclipse设置项目JDK的三个地方
商超行业微信小程序开发定制一般多少钱 （行业技术人员解读）
Markdown编辑器语言——30分钟入门到到精通
Linux系统下MongoDB的简单安装与基本操作
Power Strings
每日归档
更多
2024-05-07(14)
2024-05-06(40)
2024-05-05(0)
2024-05-04(7)
2024-05-03(19)
2024-05-02(0)
2024-05-01(4)
2024-04-30(1)
2024-04-29(40)
2024-04-28(0)

代码天地 © 2018 codetd.com

境外服务器   最新电视剧2022