常见XML解析器

xpp3

官网

http://www.extreme.indiana.edu/xgws/xsoap/xpp/

简介

Xml Pull Parser (in short XPP) is a streaming pull XML parser and should be used when there is a need to process quickly and efficiently all input elements (for example in SOAP processors).

sax

官网

http://www.saxproject.org/

简介

SAX is the Simple API for XML, originally a Java-only API. SAX was the first widely adopted API for XML in Java, and is a “de facto” standard. The current version is SAX 2.0.1, and there are versions for several programming language environments other than Java.

示例：解析微信post消息

当普通微信用户向公众账号发消息时，微信服务器将POST消息的XML数据包到开发者填写的URL上。

<xml>
 <ToUserName><![CDATA[toUser]]></ToUserName>
 <FromUserName><![CDATA[fromUser]]></FromUserName>
 <CreateTime>1348831860</CreateTime>
 <MsgType><![CDATA[text]]></MsgType>
 <Content><![CDATA[this is a test]]></Content>
 <MsgId>1234567890123456</MsgId>
</xml

以下是java代码片段：

import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

/**
 * 消息工具类
 *
 */
public class WeixinUtils {

    /**
     * 解析微信发来的请求（XML）
     *
     * @param request
     * @return
     * @throws IOException
     */
    @SuppressWarnings("unchecked")
    public static Map<String, String> parseXml(HttpServletRequest request) throws IOException {
        ServletInputStream inputStream = request.getInputStream();
        SAXReader reader = new SAXReader();
        Map<String, String> resultMap = null;
        try {
            // 这个 doc 不会是 null
            Document document = reader.read(inputStream);
            Element rootElement = document.getRootElement();
            List<Element> eList = rootElement.elements();
            resultMap = new HashMap<String, String>();
            for (Element e : eList) {
                resultMap.put(e.getName(), e.getText());
            }
        } catch (DocumentException e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) inputStream.close();
        }
        return resultMap;
    }
}

ps:

想知道 void java.io.InputStream.close() throws IOException 怎么用吗？

Ctrl+Shift+G 看看别人怎么用的吧