一 问题:
Caused by: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `com.XX.Info` (no Creators, like default construct, exist): cannot deserialize from Object value (no delegate- or property-based Creator)
at [Source: (String)"{"time":"2020-03-19 18:41:01","aa":60000}"; line: 1, column: 2]
at com.fasterxml.jackson.databind.exc.InvalidDefinitionException.from(InvalidDefinitionException.java:67)
at com.fasterxml.jackson.databind.DeserializationContext.reportBadDefinition(DeserializationContext.java:1592)
at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1058)
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1297)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:326)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:159)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4218)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3214)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3182)
就是从json字符串,反序列化为bean.
看了下报错:就是没有默认无参构造器。
public class Info implements Serializable {
/** 时间 **/
private Date time;
/** 持续时间 **/
private long aa;
public Info(Date time, long aa) {
this.time = time;
this.aa = aa;
}
//get\set
...
」
解决办法:
1. 增加默认的无参构造器。
2。 不适用jsackson,改为fastjosn。注意低版本的也会提示:
com.alibaba.fastjson.JSONException: default constructor not found.
升级到1.2.61 版本就好。