Spring Boot com.fasterxml.Jackson.databind.exc.MismatchedInputException：无法从Object值(标记“JsonToken.START_OBJECT”)反序列化“[]”类型的值

von4xj4u  于 2023-06-05  发布在  Spring
关注(0)|答案(1)|浏览(195)

我已经尝试了所有方法来读取下面的JSON字符串，但仍然得到下面的错误。我的JSON字符串是有效的，我认为问题是子元素的Map有问题。调用的API URL：

https://api.weather.gov/gridpoints/OKX/33,35/forecast

下面是我的JSON字符串：

{
"@context": [
    "https://geojson.org/geojson-ld/geojson-context.jsonld",
    {
        "@version": "1.1",
        "wx": "https://api.weather.gov/ontology#",
        "geo": "http://www.opengis.net/ont/geosparql#",
        "unit": "http://codes.wmo.int/common/unit/",
        "@vocab": "https://api.weather.gov/ontology#"
    }
],
"type": "Feature",
"geometry": {
    "type": "Polygon",
    "coordinates": [
        [
            [
                -74.025095199999996,
                40.727052399999998
            ],
            [
                -74.0295579,
                40.705361699999997
            ],
            [
                -74.000948300000005,
                40.701977499999998
            ],
            [
                -73.996479800000003,
                40.723667899999995
            ],
            [
                -74.025095199999996,
                40.727052399999998
            ]
        ]
    ]
},
"properties": {
    "updated": "2023-06-01T07:20:53+00:00",
    "units": "us",
    "forecastGenerator": "BaselineForecastGenerator",
    "generatedAt": "2023-06-01T08:08:29+00:00",
    "updateTime": "2023-06-01T07:20:53+00:00",
    "validTimes": "2023-06-01T01:00:00+00:00/P7DT11H",
    "elevation": {
        "unitCode": "wmoUnit:m",
        "value": 2.1335999999999999
    },
    "periods": [
        {
            "number": 1,
            "name": "Overnight",
            "startTime": "2023-06-01T04:00:00-04:00",
            "endTime": "2023-06-01T06:00:00-04:00",
            "isDaytime": false,
            "temperature": 59,
            "temperatureUnit": "F",
            "temperatureTrend": "rising",
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": null
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 13.333333333333334
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 83
            },
            "windSpeed": "1 mph",
            "windDirection": "NE",
            "icon": "https://api.weather.gov/icons/land/night/fog?size=medium",
            "shortForecast": "Patchy Fog",
            "detailedForecast": "Patchy fog. Mostly cloudy. Low around 59, with temperatures rising to around 61 overnight. Northeast wind around 1 mph."
        },
        {
            "number": 2,
            "name": "Thursday",
            "startTime": "2023-06-01T06:00:00-04:00",
            "endTime": "2023-06-01T18:00:00-04:00",
            "isDaytime": true,
            "temperature": 78,
            "temperatureUnit": "F",
            "temperatureTrend": "falling",
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": null
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 13.888888888888889
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 82
            },
            "windSpeed": "2 to 9 mph",
            "windDirection": "E",
            "icon": "https://api.weather.gov/icons/land/day/fog/smoke?size=medium",
            "shortForecast": "Patchy Fog then Haze",
            "detailedForecast": "Patchy fog before 8am, then haze and patchy smoke. Mostly sunny. High near 78, with temperatures falling to around 75 in the afternoon. East wind 2 to 9 mph."
        },
        {
            "number": 3,
            "name": "Thursday Night",
            "startTime": "2023-06-01T18:00:00-04:00",
            "endTime": "2023-06-02T06:00:00-04:00",
            "isDaytime": false,
            "temperature": 64,
            "temperatureUnit": "F",
            "temperatureTrend": "rising",
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": null
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 15
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 75
            },
            "windSpeed": "5 to 9 mph",
            "windDirection": "S",
            "icon": "https://api.weather.gov/icons/land/night/few/fog?size=medium",
            "shortForecast": "Mostly Clear then Patchy Fog",
            "detailedForecast": "Patchy fog after 5am. Mostly clear. Low around 64, with temperatures rising to around 66 overnight. South wind 5 to 9 mph."
        },
        {
            "number": 4,
            "name": "Friday",
            "startTime": "2023-06-02T06:00:00-04:00",
            "endTime": "2023-06-02T18:00:00-04:00",
            "isDaytime": true,
            "temperature": 84,
            "temperatureUnit": "F",
            "temperatureTrend": "falling",
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": 30
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 15.555555555555555
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 75
            },
            "windSpeed": "3 to 9 mph",
            "windDirection": "S",
            "icon": "https://api.weather.gov/icons/land/day/fog/tsra_hi,30?size=medium",
            "shortForecast": "Patchy Fog then Chance Showers And Thunderstorms",
            "detailedForecast": "Patchy fog before 8am, then a chance of showers and thunderstorms. Sunny. High near 84, with temperatures falling to around 80 in the afternoon. South wind 3 to 9 mph. Chance of precipitation is 30%."
        },
        {
            "number": 5,
            "name": "Friday Night",
            "startTime": "2023-06-02T18:00:00-04:00",
            "endTime": "2023-06-03T06:00:00-04:00",
            "isDaytime": false,
            "temperature": 62,
            "temperatureUnit": "F",
            "temperatureTrend": "rising",
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": 50
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 16.666666666666668
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 81
            },
            "windSpeed": "8 mph",
            "windDirection": "E",
            "icon": "https://api.weather.gov/icons/land/night/tsra_hi,50?size=medium",
            "shortForecast": "Chance Showers And Thunderstorms",
            "detailedForecast": "A chance of showers and thunderstorms before 8pm, then a chance of showers and thunderstorms. Mostly cloudy. Low around 62, with temperatures rising to around 66 overnight. East wind around 8 mph. Chance of precipitation is 50%. New rainfall amounts less than a tenth of an inch possible."
        },
        {
            "number": 6,
            "name": "Saturday",
            "startTime": "2023-06-03T06:00:00-04:00",
            "endTime": "2023-06-03T18:00:00-04:00",
            "isDaytime": true,
            "temperature": 67,
            "temperatureUnit": "F",
            "temperatureTrend": "falling",
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": 60
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 15
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 81
            },
            "windSpeed": "8 to 16 mph",
            "windDirection": "NE",
            "icon": "https://api.weather.gov/icons/land/day/tsra_sct,60?size=medium",
            "shortForecast": "Showers And Thunderstorms Likely",
            "detailedForecast": "Showers and thunderstorms likely. Mostly cloudy. High near 67, with temperatures falling to around 63 in the afternoon. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch possible."
        },
        {
            "number": 7,
            "name": "Saturday Night",
            "startTime": "2023-06-03T18:00:00-04:00",
            "endTime": "2023-06-04T06:00:00-04:00",
            "isDaytime": false,
            "temperature": 55,
            "temperatureUnit": "F",
            "temperatureTrend": null,
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": 60
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 10.555555555555555
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 69
            },
            "windSpeed": "17 mph",
            "windDirection": "NE",
            "icon": "https://api.weather.gov/icons/land/night/rain_showers,60/rain_showers,50?size=medium",
            "shortForecast": "Rain Showers Likely",
            "detailedForecast": "Rain showers likely. Mostly cloudy, with a low around 55. Chance of precipitation is 60%."
        },
        {
            "number": 8,
            "name": "Sunday",
            "startTime": "2023-06-04T06:00:00-04:00",
            "endTime": "2023-06-04T18:00:00-04:00",
            "isDaytime": true,
            "temperature": 65,
            "temperatureUnit": "F",
            "temperatureTrend": null,
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": 40
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 8.3333333333333339
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 69
            },
            "windSpeed": "9 to 14 mph",
            "windDirection": "NE",
            "icon": "https://api.weather.gov/icons/land/day/rain_showers,40?size=medium",
            "shortForecast": "Chance Rain Showers",
            "detailedForecast": "A chance of rain showers. Partly sunny, with a high near 65. Chance of precipitation is 40%."
        },
        {
            "number": 9,
            "name": "Sunday Night",
            "startTime": "2023-06-04T18:00:00-04:00",
            "endTime": "2023-06-05T06:00:00-04:00",
            "isDaytime": false,
            "temperature": 57,
            "temperatureUnit": "F",
            "temperatureTrend": null,
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": 40
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 9.4444444444444446
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 72
            },
            "windSpeed": "12 mph",
            "windDirection": "N",
            "icon": "https://api.weather.gov/icons/land/night/rain_showers,40?size=medium",
            "shortForecast": "Chance Rain Showers",
            "detailedForecast": "A chance of rain showers. Mostly cloudy, with a low around 57. Chance of precipitation is 40%."
        },
        {
            "number": 10,
            "name": "Monday",
            "startTime": "2023-06-05T06:00:00-04:00",
            "endTime": "2023-06-05T18:00:00-04:00",
            "isDaytime": true,
            "temperature": 68,
            "temperatureUnit": "F",
            "temperatureTrend": null,
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": 40
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 10.555555555555555
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 72
            },
            "windSpeed": "10 mph",
            "windDirection": "N",
            "icon": "https://api.weather.gov/icons/land/day/rain_showers,40/rain_showers,30?size=medium",
            "shortForecast": "Chance Rain Showers",
            "detailedForecast": "A chance of rain showers. Partly sunny, with a high near 68. Chance of precipitation is 40%."
        },
        {
            "number": 11,
            "name": "Monday Night",
            "startTime": "2023-06-05T18:00:00-04:00",
            "endTime": "2023-06-06T06:00:00-04:00",
            "isDaytime": false,
            "temperature": 60,
            "temperatureUnit": "F",
            "temperatureTrend": null,
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": 40
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 11.111111111111111
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 72
            },
            "windSpeed": "9 mph",
            "windDirection": "N",
            "icon": "https://api.weather.gov/icons/land/night/rain_showers,40?size=medium",
            "shortForecast": "Chance Rain Showers",
            "detailedForecast": "A chance of rain showers. Mostly cloudy, with a low around 60. Chance of precipitation is 40%."
        },
        {
            "number": 12,
            "name": "Tuesday",
            "startTime": "2023-06-06T06:00:00-04:00",
            "endTime": "2023-06-06T18:00:00-04:00",
            "isDaytime": true,
            "temperature": 71,
            "temperatureUnit": "F",
            "temperatureTrend": null,
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": 30
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 11.111111111111111
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 75
            },
            "windSpeed": "8 mph",
            "windDirection": "N",
            "icon": "https://api.weather.gov/icons/land/day/rain_showers,30/tsra_hi,30?size=medium",
            "shortForecast": "Chance Rain Showers",
            "detailedForecast": "A chance of rain showers before 2pm, then a chance of showers and thunderstorms. Mostly sunny, with a high near 71. Chance of precipitation is 30%."
        },
        {
            "number": 13,
            "name": "Tuesday Night",
            "startTime": "2023-06-06T18:00:00-04:00",
            "endTime": "2023-06-07T06:00:00-04:00",
            "isDaytime": false,
            "temperature": 60,
            "temperatureUnit": "F",
            "temperatureTrend": null,
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": 30
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 10.555555555555555
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 65
            },
            "windSpeed": "8 mph",
            "windDirection": "N",
            "icon": "https://api.weather.gov/icons/land/night/tsra_hi,30/tsra_hi?size=medium",
            "shortForecast": "Chance Showers And Thunderstorms",
            "detailedForecast": "A chance of showers and thunderstorms. Partly cloudy, with a low around 60. Chance of precipitation is 30%."
        },
        {
            "number": 14,
            "name": "Wednesday",
            "startTime": "2023-06-07T06:00:00-04:00",
            "endTime": "2023-06-07T18:00:00-04:00",
            "isDaytime": true,
            "temperature": 72,
            "temperatureUnit": "F",
            "temperatureTrend": null,
            "probabilityOfPrecipitation": {
                "unitCode": "wmoUnit:percent",
                "value": null
            },
            "dewpoint": {
                "unitCode": "wmoUnit:degC",
                "value": 9.4444444444444446
            },
            "relativeHumidity": {
                "unitCode": "wmoUnit:percent",
                "value": 67
            },
            "windSpeed": "9 mph",
            "windDirection": "N",
            "icon": "https://api.weather.gov/icons/land/day/rain_showers/tsra_hi?size=medium",
            "shortForecast": "Slight Chance Rain Showers then Isolated Showers And Thunderstorms",
            "detailedForecast": "A slight chance of rain showers before 2pm, then isolated showers and thunderstorms. Mostly sunny, with a high near 72."
        }
    ]
}
}

我的Java POJO

@JsonIgnoreProperties
public class Forecast {

private int number;
private String name;
private String startTime;
private String endTime;

public int getNumber() {
    return number;
}

public void setNumber(int number) {
    this.number = number;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getStartTime() {
    return startTime;
}

public void setStartTime(String startTime) {
    this.startTime = startTime;
}

public String getEndTime() {
    return endTime;
}

public void setEndTime(String endTime) {
    this.endTime = endTime;
}
}

我的控制器

@Controller
@RequestMapping("/test")
public class ConsumeController {

RestTemplate restTemplate = new RestTemplate();

@RequestMapping("/show")
public ModelAndView showForecast() {
    
    ModelAndView mv = new ModelAndView();
    mv.setViewName("show");
    
    ResponseEntity<Forecast[]> responseEntity = restTemplate.getForEntity("https://api.weather.gov/gridpoints/OKX/33,35/forecast", Forecast[].class);
    Forecast[] responseBody = responseEntity.getBody();     
    
    List<Forecast> allForeCast = Arrays.asList(responseBody);
    mv.addObject("myjson", allForeCast);
    
    System.out.println("data: " + allForeCast);
    
    return mv;
}   
}

我的JSP：

<p>List data: </p>
<c:forEach items="${myjson}" var="myjson">     
        <td>${myjson.name}</td>
        <td>${myjson.startTime}</td>        
</c:forEach>

记录器错误：

com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `[Lcom.forecast.model.Forecast;` from Object value (token `JsonToken.START_OBJECT`)
 at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 1, column: 1]
 at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59) ~[jackson-databind-2.15.0.jar:2.15.0]
 at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1752) ~[jackson-databind-2.15.0.jar:2.15.0]
 at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1526) ~[jackson-databind-2.15.0.jar:2.15.0]
 at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1473) ~[jackson-databind-2.15.0.jar:2.15.0]

如何解决他们的问题？许多感谢

spring-boot

1条答案

按热度按时间
ovfsdjhp

ovfsdjhp1#

你的问题是你的json有一个复杂的结构，你试图解析它的嵌套部分。如果我理解正确的话，你想反序列化“properties.periods”路径下的值，所以你应该改变你使用的方法。
1.手动遍历嵌套结构，到达所需的路径

ResponseEntity<String> responseEntity = restTemplate.getForEntity("https://api.weather.gov/gridpoints/OKX/33,35/forecast", String.class);
 ObjectMapper objectMapper = new ObjectMapper();
 JsonNode properties = objectMapper.readTree(responseEntity.getBody()).get("properties");
 JsonNode periods = properties.get("periods");
 Forecast[] forecasts = objectMapper.readValue(periods.toString(), Forecast[].class);

1.使用Java对象的适当嵌套来重新生成响应结构，并反序列化为父对象（这里嵌套的'Properties'类只是为了简短，最好使用简单的类）

@Data
 public class Response {

   private Properties properties;

   @Data
   public static class Properties {
     private Forecast[] periods;
   }
 }

 //

 ResponseEntity<Response> responseEntity = restTemplate.getForEntity("https://api.weather.gov/gridpoints/OKX/33,35/forecast", Response.class);

注意：在这两种情况下，您都应该注意到许多字段在所需的结果中不存在，因此请考虑适当的配置以忽略未知字段。

@JsonIgnoreProperties(ignoreUnknown = true)

上你的POJO课程，或者

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
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