java Spring Boot 批处理 - 读取 XML 输入 - 将元素转换为列表
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Spring Boot batch - reading XML input - convert elements to list
提问by Eria
I have to code a batch service, using Spring Boot, that reads an XML file as input. The structure of the XML input looks like this, and I can't change it :
我必须使用 Spring Boot 编写读取 XML 文件作为输入的批处理服务。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>
I've created my Java classes :
我已经创建了我的 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...
}
And here is my reader in the batch configuration class :
这是批处理配置类中的我的读者：
@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;
}
For now I just try to have a correct reading. But when I run the batch, I have an error :
现在我只是尝试正确阅读。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
I understand this error, but I can't find a way to correct my code. I tried to create a fake setter in Parent, adding the child to the children list. But it doesn't seem to work.
我理解这个错误，但我找不到更正我的代码的方法。我试图在 Parent 中创建一个假的 setter，将孩子添加到孩子列表中。但它似乎不起作用。
Any idea ?
任何的想法 ？
回答by Eria
I solved the problem using Jaxb2Marshaller instead of XStreamMarshaller :
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;
}
And for Java beans :
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...
}
This works fine, even with the auto-generated getters and setters : I recover a list of the children elements.
即使使用自动生成的 getter 和 setter，这也能正常工作：我恢复了子元素的列表。
回答by Jens
rename this property:
重命名此属性：
private List<Child> children;
to
到
private List<Child> child;
and recreate the getter and setter methods.
并重新创建 getter 和 setter 方法。
