documentHelper的理解与使用

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注意：Node是element的父类。

public static void main(String args[]){

String s="<?xml version=\"1.0\" encoding=\"gbk\" ?>" +
"<smartresult>" +
"<product type=\"identitycard\">" +
"<code>440305198012255411</code>" +
"<location>sdfsdf</location>" +
"<birthday>19801225</birthday>" +
"<gender>m</gender></product>" +
"</smartresult>";

                try {


       Document doc = DocumentHelper.parseText(s);
       Node root=doc.getRootElement();
       System.out.println(root.getName());




} catch (Exception e) {
e.printStackTrace();
}
}

一、DocumentHelper类的主要静态方法：

1.parseText

public static Document parseText(String text)
                          throws DocumentException

    parseText parses the given text as an XML document and returns the newly created Document.

    Parameters:
        text - the XML text to be parsed
    Returns:
        a newly parsed Document
    Throws:
        DocumentException - if the document could not be parsed

二、Document接口的主要方法：
1.getRootElement

public Element getRootElement()

    Returns the root Element for this document.

    Returns:
        the root element for this document

三、Element接口的主要方法：

1.getText(这个是element接口的方法)
返回当前元素的文本内容，如果元素没有文本内容，则返回空。

public String getText()

    Returns the text value of this element without recursing through child elements. This method iterates through all Text,CDATA and Entitynodes that this element contains and

appends the text values together.

    Specified by:
        getText in interface Node

    Returns:
        the textual content of this Element. Child elements are not navigated. This method does not return null;

2.getName（这个是node接口的方法，由于element继承node，所有，element也可以调用该方法）

public String getName()

    getName returns the name of this node. This is the XML local name of the element, attribute, entity or processing instruction. For CDATA and Text nodes this method will

return null.

    Returns:
        the XML name of this node

四、Document类的继承结构
public interface Document
extends Branch

public interface Branch
extends Node
Document接口继承Branch，Branch接口又继承Node接口，而Node接口有个方法，经常用到如下：

List<Node> selectNodes(String xpathExpression)

selectNodes evaluates an XPath expression and returns the result as a List of Node instances or String instances depending on the XPath expression.

Parameters:
xpathExpression - is the XPath expression to be evaluated
Returns:
the list of Node or String instances depending on the XPath expression

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