如何使用骆驼杰克逊JSONArray转换为对象的名单 [英] how to convert JSONArray to List of Object using camel-jackson

问题描述

上午有JSON数组的字符串如下

Am having the String of json array as follow

{"Compemployes":[
    {
        "id":1001,
        "name":"jhon"
        },
        {
                "id":1002,
        "name":"jhon"
        }
]}

我想转换这款本jsonarray到列表＆LT; Empolyee＆GT; 。为了这个，我已经添加了Maven的依赖骆驼 - 杰克逊，也写出员工POJO类。但是当我尝试运行我的下面code

i want to convert this this jsonarray to List<Empolyee> . for this i had added the the maven dependency "camel-jackson" and also write the pojo class for employee . but when i try to run my below code

 ObjectMapper mapper = new ObjectMapper();
 List<Employe> list = mapper.readValue(jsonString, TypeFactory.collectionType(List.class, Employe.class));

正在以下的异常。

am getting the following exception.

org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.ArrayList out of START_OBJECT token
 at [Source: java.io.StringReader@43caa144; line: 1, column: 1]

有人可以请告诉我是什么失踪或做点儿什么错

can someone pls tell what am missing or doing anyting wrong

推荐答案

问题是不是在你的code，但在你的JSON：

The problem is not in your code but in your json:

{"Compemployes":[{"id":1001,"name":"jhon"}, {"id":1002,"name":"jhon"}]}

这再presents其中包含一个属性Compemployes这是列表的对象
雇员。在这种情况下，你应该创建一个对象，如：

this represents an object which contains a property Compemployes which is a list of Employee. In that case you should create that object like:

class EmployeList{
    private List<Employe> compemployes;
    (with getter an setter)
}

和反序列化JSON简单地做：

and to deserialize the json simply do:

EmployeList employeList = mapper.readValue(jsonString,EmployeList.class);

如果您的JSON应该直接重新present员工的名单应该是这样的：

If your json should directly represent a list of employees it should look like:

[{"id":1001,"name":"jhon"}, {"id":1002,"name":"jhon"}]

最后一句话：

List<Employee> list2 = mapper.readValue(jsonString, 
TypeFactory.collectionType(List.class, Employee.class));

TypeFactory.collectionType 是德precated 的你现在应该使用这样的：

TypeFactory.collectionType is deprecated you should now use something like:

List<Employee> list = mapper.readValue(jsonString,
TypeFactory.defaultInstance().constructCollectionType(List.class,  
   Employee.class));

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