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首页 > 解决方案 > 使用嵌套对象和列表反序列化 JSON。“JSON 解析错误：无法构造”

java - 使用嵌套对象和列表反序列化 JSON。“JSON 解析错误：无法构造”

问题描述

我需要反序列化这个 JSON：

{  
"order":{  
    "address": "Adress XXX",
    "status": "Open",
    "confirmationDates": "2019-04-03"
},

"orderItems": [
        {
            "description": "Item 1",
            "unitPrice": 10.5,
            "quantity": 2
        },
        {
            "description": "Item 2",
            "unitPrice": 22.5,
            "quantity": 2
        },
        {
            "description": "Item 3",
            "unitPrice": 10000.5,
            "quantity": 2
        }
    ] 
}

我正在使用 Spring Boot，并且对此正文有一个 Post 请求。

@PostMapping("/orderwithitems")
public ResponseEntity<Object> addOrderWithItems(@RequestBody OrderOrderItem orderOrderItem){...}

Wrapper 类是这个 POJO：

public class OrderOrderItem{
    private Order order;
    private List<OrderItem> orderItems;
    public OrderOrderItem(){
        orderItems = new ArrayList<>();
        order = new Order();
    }

    public OrderOrderItem(Order order, List<OrderItem> orderItems) {
        this.order = order;
        this.orderItems = orderItems;
    }
...
}

问题是当我发帖时出现此错误：

{
    "timestamp": "2019-04-04T23:04:19.640+0000",
    "status": 400,
    "error": "Bad Request",
    "message": "JSON parse error: Cannot construct instance of `com.invillia.acme.OrderController$OrderOrderItem` (although at least one Creator exists): can only instantiate non-static inner class by using default, no-argument constructor; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `com.invillia.acme.OrderController$OrderOrderItem` (although at least one Creator exists): can only instantiate non-static inner class by using default, no-argument constructor\n at [Source: (PushbackInputStream); line: 2, column: 2]",
    "path": "/orderwithitems"
}

我正在尝试遵循这些示例： https ://www.baeldung.com/jackson-collection-array

https://www.baeldung.com/spring-rest-template-list

但我找不到解决方案。

标签： javajsonspring-bootspring-mvc

解决方案

问题是我将“OrderOrderItem”声明为控制器的内部类。将 OrderOrderItem 移动到新文件可以使事情正常工作。

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