org.codehaus.jackson.map.JsonMappingException: No suitable constructor found for type

 

org.codehaus.jackson.map.JsonMappingException: No suitable constructor found 
for
type [simple type, 
class
test.jackson.Employee]: can not instantiate from JSON object (need to add/enable type information?)
 
at [Source: c:\temp\employee.json; line: 
1
, column: 
2
]
    
at org.codehaus.jackson.map.JsonMappingException.from(JsonMappingException.java:
163
)
    
at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:
483
)
    
at org.codehaus.jackson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:
350
)
    
at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:
2395
)
    
at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:
1549
)
    
at test.jackson.JSONToJavaExample.main(JSONToJavaExample.java:
19
)

一般来说，解决上面问题从下面几个方面入手：

1、是否缺少默认构造函数

2、是否是类的访问修饰符问题，即jackson访问不到。