FasterXML Jackson-DataFormat-xml序列化版本和编码未添加到xml

Question

<?xml version="1.0" encoding="utf-8"?>
<SampleRequest>
... 
</SampleRequest>

但我只有这个

<SampleRequest>
... 
</SampleRequest>

jackson fasterxml Anotation中是否需要添加任何配置。

Answer 1

您可以配置XMLMapper来编写XML标头。

XmlMapper xmlMapper = new XmlMapper();
xmlMapper.configure( ToXmlGenerator.Feature.WRITE_XML_DECLARATION, true );

例如：

import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import com.fasterxml.jackson.dataformat.xml.ser.ToXmlGenerator;
import java.io.IOException;

public class Xml {
    public static void main(String[] args) throws IOException {
     // Important: create XmlMapper; it will use proper factories, workarounds
        XmlMapper xmlMapper = new XmlMapper();
        xmlMapper.configure(ToXmlGenerator.Feature.WRITE_XML_DECLARATION, true);
        xmlMapper.writeValue(System.out, new SampleRequest());
    }
}

class SampleRequest{
    public int x = 1;
    public int y = 2;
}

这将生成输出：

<?xml version="1.0" encoding="UTF-8"?>
<SampleRequest>
   ...
</SampleRequest>

public static final String P_USE_DOUBLE_QUOTES_IN_XML_DECL="com.ctc.wstx.useDoubleQuotesInXmlDecl";