Java 简单 XML 转换器将元素写入 OutputNode

Question

简单 XML 允许您制作自己的转换器。

This write method is used to serialize an object to XML. The serialization should be performed in such a way that all of the objects values are represented by an element or attribute of the provided node. This ensures that it can be fully deserialized at a later time.

@Convert(MyClass.Converter.class)
public class MyClass {
  public MyClass() {}

  public static class Converter implements Converter<MyClass> {
    public MyClass read(InputNode node) {
      return new MyClass();
    }

    public void write(OutputNode node, MyClass value) {

    }
  }
}

文档描述了在 OutputNode 中表示一个元素，那么如何向 OutputNode 添加一个元素？ OutputNode 的文档似乎没有任何向其添加元素或节点的方法。

Answer 1

您可以手动添加元素，也可以使用另一个 Serializer 添加它 -- 序列化程序也可以 write/read to/from 个节点。

这是一个例子：

@Root(name = "MyClass") // @Root required
@Convert(MyClass.MyClassConverter.class)
public class MyClass
{
    private int value;
    private String name;

    /* Ctor, getter, setter etc. */


    public static class MyClassConverter implements Converter<MyClass>
    {
        @Override
        public MyClass read(InputNode node) throws Exception
        {
            MyClass mc = new MyClass();

            /* Read the (int) value of 'someValue' node */
            int value = Integer.parseInt(node.getNext("someValue").getValue());
            mc.setValue(value);

            /* Same for the string */
            String name = node.getNext("someString_" + value).getValue();
            mc.setName(name);

            /* Do something with data not used in MyClass, but useable anyway */
            if( node.getNext("from") == null )
            {
                throw new IllegalArgumentException("Node 'from' is missing!");
            }

            return mc;
        }


        @Override
        public void write(OutputNode node, MyClass value) throws Exception
        {
            /* Add an attribute to the root node */
            node.setAttribute("example", "true");

            OutputNode valueNode = node.getChild("someValue");      // Create a child node ...
            valueNode.setAttribute("stack", "overflow");            // ... with an attribute
            valueNode.setValue(String.valueOf(value.getValue()));   // ... and a value

            /*
             * Converter allow a dynamic creation -- here the node names is
             * created from two values of MyClass
             */
            node.getChild("someString_" + value.getValue())     // Create another child node ...
                    .setValue(value.getName());                 // ... with a value only

            /* Create another node from scratch */
            OutputNode fromNode = node.getChild("from");
            fromNode.setValue("scratch");
            fromNode.setComment("This node is created by the converter");
        }

    }

}

xml写/读：

<MyClass example="true">
   <someValue stack="overflow">27</someValue>
   <someString_27>abc</someString_27>
   <!-- This node is created by the converter -->
   <from>scratch</from>
</MyClass>

重要：你必须使用AnnotationStrategy，否则@Convert将无法工作。

Serializer ser = new Persister(new AnnotationStrategy())
ser.write(...);

Java 简单 XML 转换器将元素写入 OutputNode

Java Simple XML Converter write element to OutputNode

java

xml-parsing

simple-framework