public static void main(String[] args) {
		ResponseResult r = new ResponseResult();
		ResultFaceid rf = new ResultFaceid();
		Threshold t = r.new Threshold();
		t.setIe_3(1f);
		t.setIe_4(2f);
		t.setIe_5(3f);
		t.setIe_6(4f);
		rf.setThresholds(t);
		rf.setConfidence(1.2f);
		r.setResult_faceid(rf);
		r.setTime_userd(1111);
		r.setRequest_id("asdfsdf");
		String jsonstr = JSON.toJSONString(r);
		System.out.println(jsonstr);
		Gson gson = new Gson();
		gson.fromJson(jsonstr, ResponseResult.class);
		JSON.parseObject(jsonstr, ResponseResult.class);
	}

上面代码生成的json字符串
{"httpStatus":0,"request_id":"asdfsdf","result_faceid":{"confidence":1.2,"thresholds":{"ie_3":1,"ie_4":2,"ie_5":3,"ie_6":4}},"time_userd":1111}
再解析成对象，用gson可以，但用fastjson却报错

Exception in thread "main" com.alibaba.fastjson.JSONException: create instance error, class com.eric.ResponseResult$Threshold
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.createInstance(JavaBeanDeserializer.java:116)
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.deserialze(JavaBeanDeserializer.java:323)
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.deserialze(JavaBeanDeserializer.java:135)
	at com.alibaba.fastjson.parser.deserializer.DefaultFieldDeserializer.parseField(DefaultFieldDeserializer.java:33)
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.parseField(JavaBeanDeserializer.java:420)
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.deserialze(JavaBeanDeserializer.java:330)
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.deserialze(JavaBeanDeserializer.java:135)
	at com.alibaba.fastjson.parser.deserializer.DefaultFieldDeserializer.parseField(DefaultFieldDeserializer.java:33)
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.parseField(JavaBeanDeserializer.java:420)
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.deserialze(JavaBeanDeserializer.java:330)
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.deserialze(JavaBeanDeserializer.java:135)
	at com.alibaba.fastjson.parser.DefaultJSONParser.parseObject(DefaultJSONParser.java:551)
	at com.alibaba.fastjson.JSON.parseObject(JSON.java:250)
	at com.alibaba.fastjson.JSON.parseObject(JSON.java:226)
	at com.alibaba.fastjson.JSON.parseObject(JSON.java:185)
	at com.alibaba.fastjson.JSON.parseObject(JSON.java:303)
	at com.eric.ResponseResult.main(ResponseResult.java:48)
Caused by: java.lang.IllegalArgumentException: argument type mismatch
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
	at com.alibaba.fastjson.parser.deserializer.JavaBeanDeserializer.createInstance(JavaBeanDeserializer.java:113)
	... 16 more

不知道原因是不是有2层类引用的关系