Question

当将对象序列化为XML并使用来指定属性的名称空间时 @JacksonXmlRootElement(namespace = "http://...") 杰克逊会将“ wstxns1”附加或添加到名称空间中。例如，假设我们有以下类：

VtexSkuAttributeValues.java

@JacksonXmlRootElement(localName = "listStockKeepingUnitName")
public class VtexSkuAttributeValues {

    @JacksonXmlProperty(localName = "StockKeepingUnitFieldNameDTO", namespace = "http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts")
    @JacksonXmlElementWrapper(useWrapping = false)
    private VtexSkuAttributeValue[] stockKeepingUnitFieldNameDTO;

    public VtexSkuAttributeValue[] getStockKeepingUnitFieldNameDTO() {
        return stockKeepingUnitFieldNameDTO;
    }

    public void setValues(VtexSkuAttributeValue[] values) {
        this.stockKeepingUnitFieldNameDTO = values;
    }
}

VtexSkuAttributeValue.java

@JacksonXmlRootElement(localName = "StockKeepingUnitFieldNameDTO", namespace = "http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts")
public class VtexSkuAttributeValue {

    private String fieldName;
    private FieldValues fieldValues;
    private int idSku;

    public int getIdSku() {
        return idSku;
    }

    public String getFieldName() {
        return fieldName;
    }

    public FieldValues getFieldValues() {
        return fieldValues;
    }

    public void setIdSku(int idSku) {
        this.idSku = idSku;
    }

    public void setFieldName(String fieldName) {
        this.fieldName = fieldName;
    }

    public void setFieldValues(FieldValues fieldValues) {
        this.fieldValues = fieldValues;
    }

    @JacksonXmlRootElement(localName = "fieldValues", namespace = "http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts")
    public static class FieldValues {
        @JacksonXmlProperty(namespace = "http://schemas.microsoft.com/2003/10/Serialization/Arrays")
        @JacksonXmlElementWrapper(useWrapping = false)
        public String[] string;

        public String[] getString() {
            return string;
        }

        public void setValues(String[] values) {
            this.string = values;
        }
    }
}

然后我使用XmlMapper进行序列化并获取：

<listStockKeepingUnitName>
    <wstxns1:StockKeepingUnitFieldNameDTO xmlns:wstxns1="http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts">
        <fieldName>talle</fieldName>
        <fieldValues>
            <wstxns2:string xmlns:wstxns2="http://schemas.microsoft.com/2003/10/Serialization/Arrays">6184</wstxns2:string>
        </fieldValues>
        <idSku>258645</idSku>
    </wstxns1:StockKeepingUnitFieldNameDTO>
    <wstxns3:StockKeepingUnitFieldNameDTO xmlns:wstxns3="http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts">
        <fieldName>color</fieldName>
        <fieldValues>
            <wstxns4:string xmlns:wstxns4="http://schemas.microsoft.com/2003/10/Serialization/Arrays">6244</wstxns4:string>
        </fieldValues>
        <idSku>258645</idSku>
    </wstxns3:StockKeepingUnitFieldNameDTO>
</listStockKeepingUnitName>

即使这是有效的XML，我正在使用的Web服务也不接受它。我调试了它，这是由于杰克逊出于某种原因添加的标签中的wstxns属性所致。有没有一种方法可以防止Jackson将其添加到标签中。我唯一能想到的解决方法是在生成的XML上执行string.replaceAll，但这显然并不理想。

Answer 1

要写XML Jackson，请使用javax.xml.stream.XMLStreamWriter。您可以配置该类的实例，并为名称空间定义自己的前缀，并在需要时设置默认值。为此，我们需要扩展com.fasterxml.jackson.dataformat.xml.XmlFactory类并重写创建XMLStreamWriter实例的方法。示例实现如下所示：

class NamespaceXmlFactory extends XmlFactory {

    private final String defaultNamespace;
    private final Map<String, String> prefix2Namespace;

    public NamespaceXmlFactory(String defaultNamespace, Map<String, String> prefix2Namespace) {
        this.defaultNamespace = Objects.requireNonNull(defaultNamespace);
        this.prefix2Namespace = Objects.requireNonNull(prefix2Namespace);
    }

    @Override
    protected XMLStreamWriter _createXmlWriter(IOContext ctxt, Writer w) throws IOException {
        XMLStreamWriter writer = super._createXmlWriter(ctxt, w);
        try {
            writer.setDefaultNamespace(defaultNamespace);
            for (Map.Entry<String, String> e : prefix2Namespace.entrySet()) {
                writer.setPrefix(e.getKey(), e.getValue());
            }
        } catch (XMLStreamException e) {
            StaxUtil.throwAsGenerationException(e, null);
        }
        return writer;
    }
}

您可以按以下方式使用它：

import com.fasterxml.jackson.core.io.IOContext;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.dataformat.xml.XmlFactory;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
import com.fasterxml.jackson.dataformat.xml.util.StaxUtil;

import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;
import java.io.IOException;
import java.io.Writer;
import java.util.Collections;
import java.util.Map;
import java.util.Objects;

public class XmlMapperApp {

    public static void main(String[] args) throws Exception {
        String defaultNamespace = "http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts";
        Map<String, String> otherNamespaces = Collections.singletonMap("a", "http://schemas.microsoft.com/2003/10/Serialization/Arrays");

        XmlMapper xmlMapper = new XmlMapper(new NamespaceXmlFactory(defaultNamespace, otherNamespaces));
        xmlMapper.enable(SerializationFeature.INDENT_OUTPUT);

        System.out.println(xmlMapper.writeValueAsString(new VtexSkuAttributeValues()));
    }
}

在VtexSkuAttributeValues类中，您可以声明：

public static final String DEF_NMS = "http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts";

，并将其用于应该用作默认名称空间的每个类和字段。例如：

@JacksonXmlProperty(localName = "StockKeepingUnitFieldNameDTO", namespace = DEF_NMS)

对于不想更改名称的属性，可以使用：

@JacksonXmlProperty(namespace = VtexSkuAttributeValues.DEF_NMS)

上面的代码会打印一些随机数据：

<listStockKeepingUnitName>
  <StockKeepingUnitFieldNameDTO xmlns="http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts">
    <fieldName>Name1</fieldName>
    <fieldValues>
      <a:string xmlns:a="http://schemas.microsoft.com/2003/10/Serialization/Arrays">6184</a:string>
    </fieldValues>
    <idSku>123</idSku>
  </StockKeepingUnitFieldNameDTO>
  <StockKeepingUnitFieldNameDTO xmlns="http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts">
    <fieldName>Name1</fieldName>
    <fieldValues>
      <a:string xmlns:a="http://schemas.microsoft.com/2003/10/Serialization/Arrays">6184</a:string>
    </fieldValues>
    <idSku>123</idSku>
  </StockKeepingUnitFieldNameDTO>
</listStockKeepingUnitName>

如果不是您想要的，则可以使用该代码并尝试其他可用于配置此实例的方法。

使用版本Jackson中的2.9.9创建此示例。

Answer 2

这似乎是丢失的部分。它允许您设置前缀和名称空间。

   static class NamespaceXmlFactory extends XmlFactory {

    private final String defaultNamespace;
    private final Map<String, String> prefix2Namespace;

    public NamespaceXmlFactory(String defaultNamespace, Map<String, String> prefix2Namespace) {
        this.defaultNamespace = Objects.requireNonNull(defaultNamespace);
        this.prefix2Namespace = Objects.requireNonNull(prefix2Namespace);
    }

    @Override
    protected XMLStreamWriter _createXmlWriter(IOContext ctxt, Writer w) throws IOException {
        XMLStreamWriter2 writer = (XMLStreamWriter2)super._createXmlWriter(ctxt, w);
        try {
            writer.setDefaultNamespace(defaultNamespace);
            writer.setPrefix("xsi", "http://www.w3.org/2001/XMLSchema-instance");
            for (Map.Entry<String, String> e : prefix2Namespace.entrySet()) {
                writer.setPrefix(e.getKey(), e.getValue());
            }
        } catch (XMLStreamException e) {
            StaxUtil.throwAsGenerationException(e, null);
        }
        return writer;
    }
}

我唯一剩下的问题是

    @JacksonXmlProperty(localName = "@xsi.type", isAttribute = true, namespace = "http://www.w3.org/2001/XMLSchema-instance")
@JsonProperty("@xsi.type")
private String type;

创建以下输出：

仍然尝试解决如何使其变为xsi：type =“ networkObjectGroupDTO”的问题。

阻止Jackson XML映射器将wstxns添加到名称空间

2 个答案: