JSON parse error: Cannot deserialize instance of `java.util.ArrayList` out of START

描述：

在前后端传递参数时，如果为JSON，后端使用@RequestBody对象类型接受数据，会出现 500/503错误。编译器同时报警告2020-07-02 16:57:19.774 WARN 16080 --- [io-7006-exec-10] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved [org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot deserialize instance of `java.util.ArrayList<com.xxx.xxx.model.order.OrderDetail>` out of START_OBJECT token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `java.util.ArrayList<com.xxx.xxx.model.order.OrderDetail>` out of START_OBJECT token at [Source: (PushbackInputStream); line: 1, column: 171] (through reference chain: com.xxx.xxx.model.order.OrderInfo["orderDetailList"])]

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警告内容：[org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot deserialize instance of `java.util.ArrayList<com.xxx.xxx.model.order.OrderInfo>` out of START_OBJECT token com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `java.util.ArrayList<com.xxx.xxx.model.order.OrderInfo>` out of START_OBJECT token at [Source: (PushbackInputStream) 也就是说，在前后端发送数据时，出现JSON格式转换错误，从而访问不到后台接口。不添加 @RequestBody 虽然可以成功访问，但是无法获取到对象数据

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解决

不要使用对象类型接受，统一使用 Map 接收数据，就不会出现上述情况@RequestBody Map<String, Object> data@PostMapping("/xxxx/xxxxx") public Result submitOrder(@RequestParam("xxxx") String tradeNo, @RequestBody Map<String, Object> data) { return Result.ok(); }