将JSON字符串转换为“Object.class” [英] Convert JSON string to "Object.class"

问题描述

我目前正在尝试使用Jackson将对象转换为JSON字符串，这很容易通过

I am currently trying to use Jackson to turn an object into a JSON string this was easily done by

public byte[] toJSON(Object obj) throws IOException {
        ObjectMapper map = new ObjectMapper();
        return map.writeValueAsString(obj).getBytes();
    }

我遇到麻烦的地方是我要拿字节数组和把它们变成一个对象。目前我有：

Where i run into trouble is when i was to take the array of bytes and turn them into an Object. Currently i have:

public Object toObject(byte[] bytes) throws IOException, ClassNotFoundException {
    ObjectMapper map = new ObjectMapper();
    return (Object)map.readValue(bytes, Object.class);
}

我成功将对象转换为JSON字符串，但是从toObject返回了Object方法总是一个LinkedHashMap而不是最初变成JSON字符串的对象。

I successfully convert an object to a JSON string but the Object returned from the toObject method is always a LinkedHashMap instead of the object that was initially turned into the JSON string.

很抱歉，如果我在沟通我的问题上做得不好但是生病了，试着总结一下只是。我希望我的代码能够执行以下操作：

Sorry if i did a poor job communicating my problem but ill try to sum it up simply. I want my code to be able to do the following:

MyClass someObject = new MyClass();
String json = toJSON(someObject);
Object tempObject = toObject(json);
MyClass sameObject = (MyClass) tempObject;

此代码目前抛出以下内容：

this code currently throws the following:

java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to com.MyClass

任何有关此事的帮助都将不胜感激！

Any help on the matter would be appreciated!

推荐答案

您正在申请对象，因此杰克逊创建了一个对象它知道它可以创建： Map 。 JSON数组将成为 List 等等。

You are requesting an Object, so Jackson creates one Object it knows it can create: a Map. JSON array would become a List and so on.

如果你想要 MyClass ，您必须明确地请求它，或者，如果您想要通用序列化/反序列化，请包含类型标识符，如@csd所示。

If you want MyClass, you must request it explicitly, or, if you want a general-purpose serialization/deserialization, for inclusion of type identifier, as suggested by @csd.

这篇关于将JSON字符串转换为“Object.class”的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！