如何使用 Jackson 反序列化对象数组

How to use Jackson to deserialise an array of objects(如何使用 Jackson 反序列化对象数组)

问题描述

Jackson 数据绑定文档 表明 Jackson 支持反序列化所有支持类型的数组"，但我可以'不知道确切的语法.

The Jackson data binding documentation indicates that Jackson supports deserialising "Arrays of all supported types" but I can't figure out the exact syntax for this.

对于单个对象，我会这样做:

For a single object I would do this:

//json input
{
    "id" : "junk",
    "stuff" : "things"
}

//Java
MyClass instance = objectMapper.readValue(json, MyClass.class);

现在对于一个数组我想这样做:

Now for an array I want to do this:

//json input
[{
    "id" : "junk",
    "stuff" : "things"
},
{
    "id" : "spam",
    "stuff" : "eggs"
}]

//Java
List<MyClass> entries = ?

有人知道是否有一个神奇的缺失命令吗?如果不是，那么解决办法是什么?

Anyone know if there is a magic missing command? If not then what is the solution?

推荐答案

首先创建一个mapper:

First create a mapper :

import com.fasterxml.jackson.databind.ObjectMapper;// in play 2.3
ObjectMapper mapper = new ObjectMapper();

作为数组:

MyClass[] myObjects = mapper.readValue(json, MyClass[].class);

作为列表:

List<MyClass> myObjects = mapper.readValue(jsonInput, new TypeReference<List<MyClass>>(){});

另一种指定List类型的方法:

Another way to specify the List type:

List<MyClass> myObjects = mapper.readValue(jsonInput, mapper.getTypeFactory().constructCollectionType(List.class, MyClass.class));

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