简单的解析xml

1、实现将文件读取。

2、然后使用xpath进行解析。

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Node;
import org.dom4j.XPath;

public class ParseXML {

	/**
	 * 根据xpath表达式解析 xml
	 * @param document
	 * @param xpathExp
	 * @return
	 */
    public static String xpath(String xml, String xpathExp) {
		Document document=null;
		System.out.println(xml);
		try {
			document = DocumentHelper.parseText(xml);
		} catch (DocumentException e) {
			e.printStackTrace();
		}
        XPath xpath = document.createXPath(xpathExp);
        Node node = xpath.selectSingleNode(document);
        if (node != null) {
        	//取值 
            String val = node.getStringValue();
          //  System.out.println(node.asXML());
            return node.asXML();
        }
        return null;
    }
    
    /**
     * 读取文件
     * @param fileName
     * @return
     */
    public static String readFile(String fileName) {
    	StringBuilder sb = new StringBuilder();
    	InputStream f=null;
    	BufferedReader br=null; 
    	try {
			f = new FileInputStream(fileName);
			br = new BufferedReader(new InputStreamReader(f));
				String line="";
				while ((line = br.readLine()) != null) {
					sb.append(line);
				}
				if(sb.length()>0) {
					return sb.toString();
				}
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			try {
			if(br!=null)
				br.close();
			if(br!=null)
				f.close();
			} catch(Exception e) {
				e.printStackTrace();
			}
		}
		return null;
    }
    
    public static void main(String[] args) {
    	//将
		String str = readFile("signpay.xml");
		//获取signpay.xml中head的值
		System.out.println(xpath(str,"/*/head"));
	}
}