如何使用Jackson
ObjectMapper
读取下面的JSON
?我已经开发了代码,但出现以下错误。
com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `java.util.ArrayList` out of START_OBJECT token
at [Source: (File); line: 7, column: 19] (through reference chain: com.example.demo.resources.Orgnization["secondaryIds"])
JSON
{
"id": "100000",
"name": "ABC",
"keyAccount": false,
"phone": "1111111",
"phoneExtn": "11",
"secondaryIds": {
"ROP": [
"700010015",
"454546767",
"747485968",
"343434343"
],
"AHID": [
"01122006",
"03112001"
]
}
}
最佳答案
您需要启用ACCEPT_SINGLE_VALUE_AS_ARRAY特征。可能在 POJO
中,您有一个 List
,但是当 List
中只有一个元素时,会生成 JSON
有效负载数组括号。
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);
}
}
关于java - com.fasterxml.jackson.databind.exc.MismatchedInputException : Cannot deserialize instance of `java.util.ArrayList` out of START_OBJECT token,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/58539657/