SpringBoot中測試Elasticsearch，在測試ElasticsearchRepository文件操作中的查詢時報錯org.springframework.data.elasticsearch.ElasticsearchException: failed to map source **
阿新 • • 發佈：2018-12-04
問題描述：
在SpringBoot中測試Elasticsearch的時候，當測試ElasticsearchRepository的文件操作的時候，在呼叫find()查詢方法時報錯，錯誤如下：
com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `com.zmx.elasticsearch.pojo.Item` (no Creators, like default construct, exist): cannot deserialize from Object value (no delegate- or property-based Creator) at [Source: (String); line: 1, column: 2] at com.fasterxml.jackson.databind.exc.InvalidDefinitionException.from(InvalidDefinitionException.java:67) at com.fasterxml.jackson.databind.DeserializationContext.reportBadDefinition(DeserializationContext.java:1452) at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1028) 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:4013) at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3004) at org.springframework.data.elasticsearch.core.DefaultEntityMapper.mapToObject(DefaultEntityMapper.java:82) at org.springframework.data.elasticsearch.core.AbstractResultMapper.mapEntity(AbstractResultMapper.java:43) ... 56 more
原因：
這是因為在實體類Item中為了方便例項化添加了一個有參建構函式，導致JVM不能新增預設的無參構造函數了，但是jackson的反序列化需要使用無參建構函式，所以報錯！
解決：
在實體類Item中新增一個無參建構函式就可以了！