我必须使用Spring Boot编写一个批处理服务,它读取XML文件作为输入。XML输入的结构如下所示,我无法更改它:
<root>
<parent>
<field1>string</field1>
<field2>string</field2>
<field3>string</field2>
<child>
<fieldA>string</fieldA>
<fieldB>string</fieldB>
</child>
<child>
<fieldA>string</fieldA>
<fieldB>string</fieldB>
</child>
<child>
<fieldA>string</fieldA>
<fieldB>string</fieldB>
</child>
</parent>
</root>
我已经创建了Java类:
public class Parent {
private String field1;
private String field2;
private String field3;
private List<Child> children;
// Getters and setters...
}
public class Child {
private String fieldA;
private String fieldB;
// Getters and setters...
}
下面是我在批处理配置类中的reader:
@Bean
public ItemReader<Object> reader(){
StaxEventItemReader<Object> reader = new StaxEventItemReader<Object>();
reader.setResource( new ClassPathResource("input.xml") );
reader.setFragmentRootElementName("parent");
XStreamMarshaller unmarshaller = new XStreamMarshaller();
Map<String, Class> aliases = new HashMap<String, Class>();
aliases.put( "parent", Parent.class );
aliases.put( "child", Child.class );
unmarshaller.setAliases(aliases);
reader.setUnmarshaller( unmarshaller );
return reader;
}
现在我只是试着有一个正确的读数。但是当我运行批处理时,我有一个错误:
org.springframework.oxm.UnmarshallingFailureException: XStream unmarshalling exception; nested exception is com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter$UnknownFieldException: No such field foo.bar.Parent.child
我理解这个错误,但是我找不到一个方法来纠正我的代码。我尝试在Parent中创建一个伪setter,将child添加到children列表中。但它似乎不起作用。
我使用Jaxb2Marshaller而不是XStreamMarshaller解决了这个问题:
@Bean
public ItemReader<Object> reader(){
StaxEventItemReader<Object> reader = new StaxEventItemReader<Object>();
reader.setResource( new ClassPathResource("input.xml") );
reader.setFragmentRootElementName("parent");
Jaxb2Marshaller unmarshaller = new Jaxb2Marshaller();
unmarshaller.setClassesToBeBound( Parent.class, Child.class );
reader.setUnmarshaller( unmarshaller );
return reader;
}
对于Java bean:
@XmlRootElement(name = "parent")
public class Parent {
private String field1;
private String field2;
private String field3;
private List<Child> child;
// Getters and setters...
}
public class Child {
private String fieldA;
private String fieldB;
// Getters and setters...
}
这工作得很好,即使使用自动生成的getter和setter:我恢复了子元素的列表。
重命名此属性:
private List<Child> children;
private List<Child> child;