我有一個 REST 服務，它呼叫一個回傳 XML 回應的外部端點。
專案依賴基本上是Lombok、spring starter web和jackson。
<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
<version>2.13.3</version>
</dependency>
這是呼叫端點后收到的當前 XML 回應：
<?xml version="1.0" encoding="UTF-8"?>
<Publication_MarketDocument xmlns="urn:iec62325.351:tc57wg16:451-3:publicationdocument:7:0">
<mRID>032af514c4a34ede9911c84cda33a547</mRID>
<revisionNumber>1</revisionNumber>
<type>A44</type>
<sender_MarketParticipant.mRID codingScheme="A01">10X1001A1001A450</sender_MarketParticipant.mRID>
<sender_MarketParticipant.marketRole.type>A32</sender_MarketParticipant.marketRole.type>
<receiver_MarketParticipant.mRID codingScheme="A01">10X1001A1001A450</receiver_MarketParticipant.mRID>
<receiver_MarketParticipant.marketRole.type>A33</receiver_MarketParticipant.marketRole.type>
<createdDateTime>2022-09-01T12:15:32Z</createdDateTime>
<period.timeInterval>
<start>2015-12-31T23:00Z</start>
<end>2016-01-02T23:00Z</end>
</period.timeInterval>
<TimeSeries>
<mRID>1</mRID>
<businessType>A62</businessType>
<in_Domain.mRID codingScheme="A01">10YCZ-CEPS-----N</in_Domain.mRID>
<out_Domain.mRID codingScheme="A01">10YCZ-CEPS-----N</out_Domain.mRID>
<currency_Unit.name>EUR</currency_Unit.name>
<price_Measure_Unit.name>MWH</price_Measure_Unit.name>
<curveType>A01</curveType>
<Period>
<timeInterval>
<start>2015-12-31T23:00Z</start>
<end>2016-01-01T23:00Z</end>
</timeInterval>
<resolution>PT60M</resolution>
<Point>
<position>1</position>
<price.amount>16.50</price.amount>
</Point>
<Point>
<position>2</position>
<price.amount>15.50</price.amount>
</Point>
<Point>
<position>3</position>
<price.amount>14.00</price.amount>
</Point>
<Point>
<position>4</position>
<price.amount>10.01</price.amount>
</Point>
<Point>
<position>5</position>
<price.amount>8.97</price.amount>
</Point>
<Point>
<position>6</position>
<price.amount>12.23</price.amount>
</Point>
<Point>
<position>7</position>
<price.amount>12.10</price.amount>
</Point>
<Point>
<position>8</position>
<price.amount>14.00</price.amount>
</Point>
<Point>
<position>9</position>
<price.amount>5.00</price.amount>
</Point>
<Point>
<position>10</position>
<price.amount>10.01</price.amount>
</Point>
<Point>
<position>11</position>
<price.amount>14.50</price.amount>
</Point>
<Point>
<position>12</position>
<price.amount>5.00</price.amount>
</Point>
<Point>
<position>13</position>
<price.amount>6.00</price.amount>
</Point>
<Point>
<position>14</position>
<price.amount>11.05</price.amount>
</Point>
<Point>
<position>15</position>
<price.amount>21.00</price.amount>
</Point>
<Point>
<position>16</position>
<price.amount>25.00</price.amount>
</Point>
<Point>
<position>17</position>
<price.amount>31.20</price.amount>
</Point>
<Point>
<position>18</position>
<price.amount>34.02</price.amount>
</Point>
<Point>
<position>19</position>
<price.amount>35.00</price.amount>
</Point>
<Point>
<position>20</position>
<price.amount>34.50</price.amount>
</Point>
<Point>
<position>21</position>
<price.amount>34.03</price.amount>
</Point>
<Point>
<position>22</position>
<price.amount>30.00</price.amount>
</Point>
<Point>
<position>23</position>
<price.amount>28.13</price.amount>
</Point>
<Point>
<position>24</position>
<price.amount>21.80</price.amount>
</Point>
</Period>
</TimeSeries>
<TimeSeries>
<mRID>2</mRID>
<businessType>A62</businessType>
<in_Domain.mRID codingScheme="A01">10YCZ-CEPS-----N</in_Domain.mRID>
<out_Domain.mRID codingScheme="A01">10YCZ-CEPS-----N</out_Domain.mRID>
<currency_Unit.name>EUR</currency_Unit.name>
<price_Measure_Unit.name>MWH</price_Measure_Unit.name>
<curveType>A01</curveType>
<Period>
<timeInterval>
<start>2016-01-01T23:00Z</start>
<end>2016-01-02T23:00Z</end>
</timeInterval>
<resolution>PT60M</resolution>
<Point>
<position>1</position>
<price.amount>0.01</price.amount>
</Point>
<Point>
<position>2</position>
<price.amount>1.00</price.amount>
</Point>
<Point>
<position>3</position>
<price.amount>0.01</price.amount>
</Point>
<Point>
<position>4</position>
<price.amount>0.01</price.amount>
</Point>
<Point>
<position>5</position>
<price.amount>2.01</price.amount>
</Point>
<Point>
<position>6</position>
<price.amount>1.00</price.amount>
</Point>
<Point>
<position>7</position>
<price.amount>0.01</price.amount>
</Point>
<Point>
<position>8</position>
<price.amount>1.00</price.amount>
</Point>
<Point>
<position>9</position>
<price.amount>5.11</price.amount>
</Point>
<Point>
<position>10</position>
<price.amount>22.00</price.amount>
</Point>
<Point>
<position>11</position>
<price.amount>41.29</price.amount>
</Point>
<Point>
<position>12</position>
<price.amount>51.08</price.amount>
</Point>
<Point>
<position>13</position>
<price.amount>51.09</price.amount>
</Point>
<Point>
<position>14</position>
<price.amount>61.93</price.amount>
</Point>
<Point>
<position>15</position>
<price.amount>50.00</price.amount>
</Point>
<Point>
<position>16</position>
<price.amount>53.04</price.amount>
</Point>
<Point>
<position>17</position>
<price.amount>100.00</price.amount>
</Point>
<Point>
<position>18</position>
<price.amount>64.83</price.amount>
</Point>
<Point>
<position>19</position>
<price.amount>58.02</price.amount>
</Point>
<Point>
<position>20</position>
<price.amount>32.29</price.amount>
</Point>
<Point>
<position>21</position>
<price.amount>35.08</price.amount>
</Point>
<Point>
<position>22</position>
<price.amount>22.00</price.amount>
</Point>
<Point>
<position>23</position>
<price.amount>22.00</price.amount>
</Point>
<Point>
<position>24</position>
<price.amount>16.00</price.amount>
</Point>
</Period>
</TimeSeries>
</Publication_MarketDocument>
下面是我用來將上述 XML 映射到 POJO 的所有 Java 類。
PublicationMarketDocument 類
@Data
public class PublicationMarketDocument {
@JsonProperty("revisionNumber")
private String revisionNumber;
@JsonProperty("period.timeInterval")
private TimeInterval timeInterval;
@JsonProperty("TimeSeries")
private List<TimeSeries> timeSeries;
}
時間間隔類
@Data
public class TimeInterval {
@JsonProperty("start")
private String start;
@JsonProperty("end")
private String end;
}
時間序列類
@Data
public class TimeSeries {
@JsonProperty("businessType")
private String businessType;
@JsonProperty("in_Domain.mRID")
private String inDomain;
@JsonProperty("out_Domain.mRID")
private String outDomain;
@JsonProperty("currency_Unit.name")
private String currencyName;
@JsonProperty("price_Measure_Unit.name")
private String priceMeasureUnitName;
@JsonProperty("curveType")
private String curveType;
@JsonProperty("Period")
private Period period;
}
期間班
@Data
public class Period {
@JsonProperty("timeInterval")
private TimeInterval timeInterval;
@JsonProperty("resolution")
private String resolution;
@JsonProperty("Point")
private List<Point> point;
}
點類
@Data
public class Point {
@JsonProperty("position")
String position;
@JsonProperty("price.amount")
String priceAmount;
}
這是用于實際呼叫外部 API 的控制器類：
@RestController
@RequestMapping("/api/v1/")
@Slf4j
public class FetchController {
@GetMapping(value = "day-ahead-prices", produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<PublicationMarketDocument> getDayAheadPrices() {
String localUrl = URL "&periodStart=" pStart "&periodEnd=" pEnd;
RestTemplate restTemplate = new RestTemplate();
ResponseEntity<PublicationMarketDocument> response = restTemplate.getForEntity(localUrl, PublicationMarketDocument.class);
return new ResponseEntity<>(response.getBody(), HttpStatus.OK);
}
}
這是應用程式初始化時收到的錯誤：
Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.web.client.RestClientException: Error while extracting response for type [class com.example.openvpp.models.MarketDataModel] and content type [text/xml]; nested exception is org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot construct instance of `com.example.openvpp.models.TimeSeries` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('1'); nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `com.example.openvpp.models.TimeSeries` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('1')
at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 16, column: 10] (through reference chain: com.example.openvpp.models.MarketDataModel["TimeSeries"]->java.util.ArrayList[0])] with root cause
僅當我們沒有 TimeSeries 和 Point 欄位作為呼叫方類中的串列時，才會獲得以下近似結果。一旦我們將它們包裝為 List<>，就會出現問題。
{
"revisionNumber": "1",
"period.timeInterval": {
"start": "2015-12-31T23:00Z",
"end": "2016-01-01T23:00Z"
},
"TimeSeries": {
"businessType": "A62",
"in_Domain.mRID": "10YCZ-CEPS-----N",
"out_Domain.mRID": "10YCZ-CEPS-----N",
"currency_Unit.name": "EUR",
"price_Measure_Unit.name": "MWH",
"curveType": "A01",
"Period": {
"timeInterval": {
"start": "2015-12-31T23:00Z",
"end": "2016-01-01T23:00Z"
},
"resolution": "PT60M",
"Point": {
"position": "24",
"price.amount": "21.80"
}
}
}
}
我面臨的主要問題是將嵌套的 XML 欄位反序列化為 TimeSeries 和點串列物件。已經嘗試將 @JsonFormat(with = JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY) 添加到他們兩個都沒有成功。
還嘗試了此注釋 @JsonDeserialize(as=ArrayList.class, contentAs=Point.class) 但是錯誤仍然相同。
目前有沒有一種優雅的方式來做到這一點，這是杰克遜圖書館本身的一個缺點嗎？
我無法控制外部 XML 端點。此外，我不控制 ObjectMapper 實體，因為我希望 Jackson 完全將 XML 映射到 Java POJO。
PS@JacksonXmlElementWrapper(useWrapping = false)在此處添加@qdoot 建議使用注釋后獲得的最終結果。希望這對將來關注此問題的人有所幫助。
{
"revisionNumber": "1",
"period.timeInterval": {
"start": "2015-12-31T23:00Z",
"end": "2016-01-02T23:00Z"
},
"TimeSeries": [
{
"businessType": "A62",
"in_Domain.mRID": "10YCZ-CEPS-----N",
"out_Domain.mRID": "10YCZ-CEPS-----N",
"currency_Unit.name": "EUR",
"price_Measure_Unit.name": "MWH",
"curveType": "A01",
"Period": {
"timeInterval": {
"start": "2015-12-31T23:00Z",
"end": "2016-01-01T23:00Z"
},
"resolution": "PT60M",
"Point": [
{
"position": "1",
"price.amount": "16.50"
},
{
"position": "2",
"price.amount": "15.50"
},
{
"position": "3",
"price.amount": "14.00"
},
{
"position": "4",
"price.amount": "10.01"
},
{
"position": "5",
"price.amount": "8.97"
},
{
"position": "6",
"price.amount": "12.23"
},
{
"position": "7",
"price.amount": "12.10"
},
{
"position": "8",
"price.amount": "14.00"
},
{
"position": "9",
"price.amount": "5.00"
},
{
"position": "10",
"price.amount": "10.01"
},
{
"position": "11",
"price.amount": "14.50"
},
{
"position": "12",
"price.amount": "5.00"
},
{
"position": "13",
"price.amount": "6.00"
},
{
"position": "14",
"price.amount": "11.05"
},
{
"position": "15",
"price.amount": "21.00"
},
{
"position": "16",
"price.amount": "25.00"
},
{
"position": "17",
"price.amount": "31.20"
},
{
"position": "18",
"price.amount": "34.02"
},
{
"position": "19",
"price.amount": "35.00"
},
{
"position": "20",
"price.amount": "34.50"
},
{
"position": "21",
"price.amount": "34.03"
},
{
"position": "22",
"price.amount": "30.00"
},
{
"position": "23",
"price.amount": "28.13"
},
{
"position": "24",
"price.amount": "21.80"
}
]
}
},
{
"businessType": "A62",
"in_Domain.mRID": "10YCZ-CEPS-----N",
"out_Domain.mRID": "10YCZ-CEPS-----N",
"currency_Unit.name": "EUR",
"price_Measure_Unit.name": "MWH",
"curveType": "A01",
"Period": {
"timeInterval": {
"start": "2016-01-01T23:00Z",
"end": "2016-01-02T23:00Z"
},
"resolution": "PT60M",
"Point": [
{
"position": "1",
"price.amount": "0.01"
},
{
"position": "2",
"price.amount": "1.00"
},
{
"position": "3",
"price.amount": "0.01"
},
{
"position": "4",
"price.amount": "0.01"
},
{
"position": "5",
"price.amount": "2.01"
},
{
"position": "6",
"price.amount": "1.00"
},
{
"position": "7",
"price.amount": "0.01"
},
{
"position": "8",
"price.amount": "1.00"
},
{
"position": "9",
"price.amount": "5.11"
},
{
"position": "10",
"price.amount": "22.00"
},
{
"position": "11",
"price.amount": "41.29"
},
{
"position": "12",
"price.amount": "51.08"
},
{
"position": "13",
"price.amount": "51.09"
},
{
"position": "14",
"price.amount": "61.93"
},
{
"position": "15",
"price.amount": "50.00"
},
{
"position": "16",
"price.amount": "53.04"
},
{
"position": "17",
"price.amount": "100.00"
},
{
"position": "18",
"price.amount": "64.83"
},
{
"position": "19",
"price.amount": "58.02"
},
{
"position": "20",
"price.amount": "32.29"
},
{
"position": "21",
"price.amount": "35.08"
},
{
"position": "22",
"price.amount": "22.00"
},
{
"position": "23",
"price.amount": "22.00"
},
{
"position": "24",
"price.amount": "16.00"
}
]
}
}
]
}
uj5u.com熱心網友回復：
你可以試試@JacksonXmlElementWrapper
@JacksonXmlElementWrapper(useWrapping=false)
private List<Point> point;
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