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com.fasterxml.jackson.databind.exc.MismatchedInputException:无法从START_OBJECT令牌中反序列化java.util.ArrayList的实例

更新时间:2022-01-07 17:55:40

您需要启用 ACCEPT_SINGLE_VALUE_AS_ARRAY 功能。可能在 POJO 中,您有一个 List ,但是当 List JSON 有效载荷生成时不带数组括号。

You need to enable ACCEPT_SINGLE_VALUE_AS_ARRAY feature. Probably in POJO you have a List but when there is only one element in a List JSON payload is generated without array brackets.

import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.File;
import java.util.List;

public class JsonApp {

    public static void main(String[] args) throws Exception {
        File jsonFile = new File("./src/main/resources/test.json");

        ObjectMapper mapper = new ObjectMapper();
        mapper.enable(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY);

        Orgnization root = mapper.readValue(jsonFile, Orgnization.class);
        System.out.println(root);
    }
}