jackson2报错

Question

package com.pft.pves.utils;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;

public class NetUtil {
	
	public static void main(String[] args) {
		String str="{"Operation":"login","data":{"account":"sjdnbd","disabled":false,"imei":"354113060211698","password":"shdnd"}}";
		ObjectMapper mapper = new ObjectMapper();
		RequestBody<User> rb = mapper.convertValue(str, new TypeReference<RequestBody<User>>() {});
		System.out.println(rb.getOperation());
    }

	}



	





	





	错误信息Exception in thread "main" java.lang.IllegalArgumentException: Can not instantiate value of type [simple type, class com.pft.pves.utils.RequestBody<com.pft.pves.utils.User>] from String value; no single-String constructor/factory method
 at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2704)
 at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2646)
 at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2637)
 at com.pft.pves.utils.NetUtil.main(NetUtil.java:14)
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not instantiate value of type [simple type, class com.pft.pves.utils.RequestBody<com.pft.pves.utils.User>] from String value; no single-String constructor/factory method
 at com.fasterxml.jackson.databind.deser.std.StdValueInstantiator._createFromStringFallbacks(StdValueInstantiator.java:428)
 at com.fasterxml.jackson.databind.deser.std.StdValueInstantiator.createFromString(StdValueInstantiator.java:299)
 at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromString(BeanDeserializerBase.java:1150)
 at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther(BeanDeserializer.java:139)
 at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:126)
 at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2699)
 ... 3 more

              

Answer 1

rb = mapper.readValue(str, new TypeReference<RequestBody<User>>(){});

不懂了，请问convertValue是干哈的··

Answer 2

Can not instantiate value of type [simple type,class com.pft.pves.utils.RequestBody<com.pft.pves.utils.User>] from String value; no single-String constructor/factory method

这个类没有合适的构造方法,