北蔡
提纲：
1.出现的场景。
2.报错内容和代码追踪。
3.原因。
4.三种解决方案。
- 出现的场景：
a.服务端提供一个springcloud接口。
b.客户端通过feign调用该接口，返回值为一个列表的CompanyDTO,DTO中有一个Date对象。
c.调用出错。
-
报错如下：
Caused by: org.springframework.http.converter.HttpMessageNotReadableException: Could not read document: Can not deserialize value of type java.util.Date from String "2017-12-08 09:20:53": not a valid representation (error: Failed to parse Date value '2017-12-08 09:20:53': Can not parse date "2017-12-08 09:20:53Z": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSS'Z'', parsing fails (leniency? null)) at [Source: java.io.PushbackInputStream@2041c1b0; line: 1, column: 554] (through reference chain: com.qts.base.result.ResponseData["data"]->java.util.ArrayList[0]->com.qts.company.api.dto.CompanyDTO["applyRefundTime"]); nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Can not deserialize value of type java.util.Date from String "2017-12-08 09:20:53": not a valid representation (error: Failed to parse Date value '2017-12-08 09:20:53': Can not parse date "2017-12-08 09:20:53Z": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSS'Z'', parsing fails (leniency? null)) at [Source: java.io.PushbackInputStream@2041c1b0; line: 1, column: 554] (through reference chain: com.qts.base.result.ResponseData["data"]->java.util.ArrayList[0]->com.qts.company.api.dto.CompanyDTO["applyRefundTime"]) at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:228) at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:213) at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:95) 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) ... 75 more Caused by: com.fasterxml.jackson.databind.exc.InvalidFormatException: Can not deserialize value of type java.util.Date from String "2017-12-08 09:20:53": not a valid representation (error: Failed to parse Date value '2017-12-08 09:20:53': Can not parse date "2017-12-08 09:20:53Z": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSS'Z'', parsing fails (leniency? null)) at [Source: java.io.PushbackInputStream@2041c1b0; line: 1, column: 554] (through reference chain: com.qts.base.result.ResponseData["data"]->java.util.ArrayList[0]->com.qts.company.api.dto.CompanyDTO["applyRefundTime"]) 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:822) at com.fasterxml.jackson.databind.deser.std.StdDeserializer._parseDate(StdDeserializer.java:791) 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:499) at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:101) 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:277) at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:249) at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:26) at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:499) at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:101) 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:3789) at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2913) at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:225) ... 80 more
a.从AbstractJackson2HttpMessageConverter.java:225的readJavaType方法开始。
b.DateDeserializers.java的deserialize中，有一段核心逻辑：this._customFormat.parse(str)。问题来了：_customFormat是从哪里来的？
protected Date _parseDate(JsonParser p, DeserializationContext ctxt) throws IOException {
if (this._customFormat != null) {
JsonToken t = p.getCurrentToken();
if (t == JsonToken.VALUE_STRING) {
String str = p.getText().trim();
if (str.length() == 0) {
return (Date)this.getEmptyValue(ctxt);
}
DateFormat var5 = this._customFormat;
synchronized(this._customFormat) {
Date var10000;
try {
var10000 = this._customFormat.parse(str);//重点
} catch (ParseException var8) {
return (Date)ctxt.handleWeirdStringValue(this.handledType(), str, "expected format \"%s\"", new Object[]{this._formatString});
}
return var10000;
}
}
}
return super._parseDate(p, ctxt);
}
c.DateBasedDeserializer中的_customFormat，通过ctxt.getConfig()获取，DeserializationContext是配置的上下文。
protected abstract static class DateBasedDeserializer<T> extends StdScalarDeserializer<T> implements ContextualDeserializer {
protected final DateFormat _customFormat;
protected final String _formatString;
protected abstract DateDeserializers.DateBasedDeserializer<T> withDateFormat(DateFormat var1, String var2);
public JsonDeserializer<?> createContextual(DeserializationContext ctxt, BeanProperty property) throws JsonMappingException {
if (property != null) {
Value format = this.findFormatOverrides(ctxt, property, this.handledType());
if (format != null) {
TimeZone tz = format.getTimeZone();
Locale loc;
if (format.hasPattern()) {
String pattern = format.getPattern();
loc = format.hasLocale() ? format.getLocale() : ctxt.getLocale();
SimpleDateFormat df = new SimpleDateFormat(pattern, loc);
if (tz == null) {
tz = ctxt.getTimeZone();
}
df.setTimeZone(tz);
return this.withDateFormat(df, pattern);
}
if (tz != null) {
DateFormat df = ctxt.getConfig().getDateFormat();//重点
Object df;
if (df.getClass() == StdDateFormat.class) {
loc = format.hasLocale() ? format.getLocale() : ctxt.getLocale();
StdDateFormat std = (StdDateFormat)df;
std = std.withTimeZone(tz);
std = std.withLocale(loc);
df = std;
} else {
df = (DateFormat)df.clone();
((DateFormat)df).setTimeZone(tz);
}
return this.withDateFormat((DateFormat)df, this._formatString);
}
}
}
return this;
}
}
d.我们看下getDateFormat的具体实现，最终是通过MapperConfig中的BaseSettings获取。
public final DateFormat getDateFormat() {
return this._base.getDateFormat();
}
3.具体原因是Jason只支持一下几种格式：
"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"
"yyyy-MM-dd"
4.解决方案：
既然默认的序列化不支持这样的格式，那就手动设置一下。
4.1设置客户端的DateFormat。
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);
}
}
并在启动的时候加入。
@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;
}
}
4.2解决方案2
可以通过代码，那就可以通过配置。。。
#spring.mvc.date-format=yyyy-MM-dd HH:mm:ss
#spring.jackson.time-zone=GMT+8
#spring.jackson.date-format=yyyy-MM-dd HH:mm:ss
4.3解决方案3
在字段的setter上对Date对象增加注解，这种方法比较麻烦。
public class DateJsonDeserializer extends JsonDeserializer<Date> {
/**
* @see JsonDeserializer#deserialize(JsonParser,
* DeserializationContext)
*/
@Override
public Date deserialize(JsonParser parser, DeserializationContext context)
throws IOException, JsonProcessingException {
try {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return sdf.parse(parser.getValueAsString());
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
然后在DTO的字段上增加注解：
@JsonDeserialize(using = DateJsonDeserializer.class)
private Date applyRefundTime;
参考文章：
https://blog.csdn.net/qq906627950/article/details/79503801
http://wujiu.iteye.com/blog/2244537
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