Question

我正在使用JAXB将xml转换为对象。在做了一些教程后，我可以成功地将一个简单的xml（具有单个对象和唯一元素标记）转换为对象。然后我需要处理更复杂的xml，它有多个实例和一个父标记。我仍然使用类似的结构。但是我无法获得三个国家/地区对象的预期输出。我的代码出了什么问题？请帮忙。 IntelliJ IDE控制台输出是：

 Countries@5e20a82a

 Process finished with exit code 0

xml文件：

 <?xml version="1.0" encoding="UTF-8" standalone="yes"?><Countries>
<Country>
    <Country_Name>Spain</Country_Name>
    <Country_Capital>Madrid</Country_Capital>
    <Country_Continent>Europe</Country_Continent>
</Country>
<Country>
    <Country_Name>USA</Country_Name>
    <Country_Capital>Washington</Country_Capital>
    <Country_Continent>America</Country_Continent>
</Country>
<Country>
    <Country_Name>Japan</Country_Name>
    <Country_Capital>Tokyo</Country_Capital>
    <Country_Continent>Asia</Country_Continent>
</Country>
</Countries>

Countries.java

 import javax.xml.bind.annotation.XmlAttribute;
 import javax.xml.bind.annotation.XmlElement;
 import javax.xml.bind.annotation.XmlRootElement;
 import javax.xml.bind.annotation.XmlType;

@XmlType( propOrder = { "name", "capital", "foundation", "continent" ,    "population"} )
@XmlRootElement( name = "Countries" )
public class Countries {


private int population;
private String name;
private String capital;
private int importance;
private String foundation;
private String continent;

@XmlElement(name = "Country_Population")
public void setPopulation(int population) {
    this.population = population;
}

@XmlElement(name = "Country_Name")
public void setName(String name) {
    this.name = name;
}

@XmlElement(name = "Country_Capital")
public void setCapital(String capital) {
    this.capital = capital;
}

@XmlAttribute(name = "importance", required = true)
public void setImportance(int importance) {
    this.importance = importance;
}

@XmlElement(name = "Country_foundation")
public void setFoundation(String foundation) {
    this.foundation = foundation;
}

@XmlElement(name = "Country_Continent")
public void setContinent(String continent) {
    this.continent = continent;
}

}

CountryReader.java

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import java.io.File;

public class CountryReader {
public static void main(String[] args) throws JAXBException {
    File file = new File("country.xml");
    JAXBContext jaxbContext = JAXBContext.newInstance( Countries.class );
    Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
    Countries countres = (Countries)jaxbUnmarshaller.unmarshal( file );
    System.out.println( countres );
   }
 }

Answer 1

您应该将根元素和嵌套集合元素的映射分开。

所以你会有这样的事情：

@XmlRootElement( name = "Countries" )
public class Countries {
    private List<Country> countries;

    @XmlElement(name = "Country")
    public void setCountries(List<Country> countries) {
        this.countries = countries;
    }
}

@XmlType( propOrder = { "name", "capital", "foundation", "continent" ,    "population"} )
@XmlRootElement( name = "Country" )
public class Country {
    private int population;
    private String name;
    private String capital;
    private int importance;
    private String foundation;
    private String continent;

    @XmlElement(name = "Country_Population")
    public void setPopulation(int population) {
        this.population = population;
    }

    @XmlElement(name = "Country_Name")
    public void setName(String name) {
        this.name = name;
    }

    @XmlElement(name = "Country_Capital")
    public void setCapital(String capital) {
        this.capital = capital;
    }

    @XmlAttribute(name = "importance", required = true)
    public void setImportance(int importance) {
        this.importance = importance;
    }

    @XmlElement(name = "Country_foundation")
    public void setFoundation(String foundation) {
        this.foundation = foundation;
    }

    @XmlElement(name = "Country_Continent")
    public void setContinent(String continent) {
        this.continent = continent;
    }
}

有关在JAXB中处理集合的更多信息，请参阅this博文。 @XmlElementWrapper似乎适合您的任务，但我认为它不能直接用于根元素。

多实例xml文件ummarshalling到对象

1 个答案: