WebService(WEB服务)--获取网络数据

运用WebService（WEB服务），可以很方便快捷的获取想要的数据。[url]http://www.webxml.com.cn/zh_cn/index.aspx[/url]网站提供了很多web服务。下面以获取汇率为例，来说明webservice的用法。
这个例子运用到了dom4j操作xml文件，先是从两个web服务中分别获取数据，最后根据具体需求将数据整合在一起，生成一个xml文件。本例中需要用到的webservice有两个：[url]http://webservice.webxml.com.cn/WebServices/ExchangeRateWebService.asmx[/url]与[url]http://webservice.webxml.com.cn/WebServices/ForexRmbRateWebService.asmx[/url]。完整版代码见附件，精简版代码如下，哈哈

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.URL;
import java.net.URLConnection;
import java.text.DecimalFormat;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
/**
 * getExchangeRate
 */

/**
 * getForexRmbRate
 */

/**
 * 调用webservice得到汇率服务
 * @author gerry
 * 2010-09-06
 */
public class ExchangeRateXML{
	private static String encodeOut = "GBK";
	private static String encodeIn = "UTF-8";

	private static Proxy proxy;//代理
	private static String proxyStr = "10.3.1.93";//代理IP地址 若不用代理请设置proxyStr="";
	private static int proxyCode = 3128;//代理端口

	private static int COUNT = 10;//尝试连接次数

	/**
	 * 单例模式
	 */
	private static ExchangeRateXML exchangeRateXML;

	/**
	 * 私有的构造方法
	 */
	private ExchangeRateXML(){

	}

	/**
	 * public的获取单例对象的方法
	 */
	public static ExchangeRateXML getInstance(){
		if(exchangeRateXML==null){
			exchangeRateXML = new ExchangeRateXML();
			InetSocketAddress isa = new InetSocketAddress(proxyStr, proxyCode);
			proxy = new Proxy(Proxy.Type.HTTP, isa);
		}
		return exchangeRateXML;
	}


	/**
	 * 通过dom4j生成xml文件
	 * @return 成功true   失败false
	 */
	private  boolean createExchangeRateXMLFile(String fileName){
		boolean flag = false;
		Document document=null;
		SAXReader reader = new SAXReader();

		Map map = new HashMap();
		map.put("xxx", "");
		reader.getDocumentFactory().setXPathNamespaceURIs(map);

		try{
			InputStream is = getSoapInputStream(1);//得到输入流
			document=reader.read(is);//将输入流转化为document
			List list = document.selectNodes("//xxx:ExchangeRate");
			Element relativeRootElement = list.get(0).getParent().getParent();//diffgr:diffgram节点  相对根节点
			DecimalFormat df = new DecimalFormat("###0.0000"); //保留小数点后4位
			Element e = null;
			for(int i=0; i<=6; i++){  
				e = list.get(i);
				//先把名称改为"美元Currency"的格式
				e.element("Currency").setText("美元"+e.element("Currency").getText());
				e.element("Code").setText("USD-"+e.element("Code").getText());
			}

			is = getSoapInputStream(2);//得到输入流
			Document doc = reader.read(is);    //将输入流转化为document
			List l = doc.selectNodes("//xxx:ForexRmbRate");
			Element ele = null;
			for (Iterator it = l.iterator(); it.hasNext();) {
				ele = it.next();
				//ele.element("Name").setText(ele.element("Name").getText()+"人民币");
				ele.element("Name").setText(ele.element("Symbol").getText()); //为了解决在Linux上中文字符的问题
				ele.element("Symbol").setText(ele.element("Symbol").getText()+"-RMB");
			}
			Element element = (Element)doc.selectSingleNode("//xxx:getForexRmbRate");
			Element elementCopy = element.createCopy();//copy节点
			relativeRootElement.add(elementCopy);
			//或relativeRootElement.appendContent(element.getParent());

			OutputFormat format = OutputFormat.createPrettyPrint();
			format.setEncoding(encodeOut);
			format.setIndent("     ");
			XMLWriter writer = new XMLWriter(new FileWriter(new File(fileName)),format); 
			writer.write(document); 
			writer.close(); 
			flag = true;
		}catch (Exception e){
			e.printStackTrace();
		}
		return flag;
	}


	/**
	 * 从xml文件中获取数据  采用XPath
	 * @return
	 */
	@SuppressWarnings("unchecked")
	private static void getExchangeRateDataFromXMLFile(String fileName){
		SAXReader reader = new SAXReader();
		Map map = new HashMap();
		map.put("aaa", "");
		reader.getDocumentFactory().setXPathNamespaceURIs(map);
		try {
			InputStream is = new FileInputStream(fileName);
			Document document = reader.read(is);
			//上行代码也可以写成Document document = reader.read(new File(fileName));
			//找到ForexRmbRate节点
			List list = document.selectNodes("//aaa:ForexRmbRate");
			for (Iterator it = list.iterator(); it.hasNext();) {
				Element elm = it.next();
				String temp = null;
				temp = elm.element("BasePrice").getText();
				temp = elm.element("fBuyPrice").getText();
				temp = elm.element("SellPrice").getText();
			}

		} catch (DocumentException e) {
			e.printStackTrace();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
	}


	/**
	 * 用户把SOAP请求发送给服务器端，并返回服务器点返回的输入流
	 * flag : 为1时代表getExchangeRate，为2时代表getForexRmbRate
	 * @return 服务器端返回的输入流，供客户端读取
	 */
	private InputStream getSoapInputStream(int flag) throws Exception {
		//InputStreamReader isr = null;
		try {
			String soap = getSoapRequest(flag);
			if (soap == null) {
				return null;
			}
			String urlStr = null;
			String SOAPActionValue = null;
			if(flag==1){
				urlStr = "http://webservice.webxml.com.cn/WebServices/ExchangeRateWebService.asmx";
				SOAPActionValue = "http://webxml.com.cn/getExchangeRate";
			}else if(flag==2){
				urlStr = "http://webservice.webxml.com.cn/WebServices/ForexRmbRateWebService.asmx";
				SOAPActionValue = "http://webxml.com.cn/getForexRmbRate";
			}
			URL url = new URL(urlStr);
			URLConnection conn = null;
			if (!proxyStr.equals("")) {
				conn = url.openConnection(proxy);
			} else {
				conn = url.openConnection();
			}
			conn.setUseCaches(false);
			conn.setDoInput(true);
			conn.setDoOutput(true);
			conn.setRequestProperty("Content-Length", Integer.toString(soap.length()));
			conn.setRequestProperty("Content-Type", "text/xml; charset=utf-8");
			conn.setRequestProperty("SOAPAction",SOAPActionValue);
			OutputStream ops = conn.getOutputStream();
			OutputStreamWriter osw = new OutputStreamWriter(ops, encodeIn);
			osw.write(soap);
			osw.flush();
			osw.close();
			InputStream is = conn.getInputStream();
//			isr = new InputStreamReader(is, encodeIn);
//			return isr;
			return is;
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}


	/**
	 * 获取soap请求头
	 * flag : 为1时代表getExchangeRate，为2时代表getForexRmbRate
	 * @return 用户将要发送给服务器的soap请求
	 */
	private String getSoapRequest(int flag) {
		StringBuilder sb = new StringBuilder();
		if(flag==1){
			sb.append(""
				+ "				+ "xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" "
				+ "xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">"
				+ "	"
				+ "" + "A"
				+ "	"
				+ "");
		}else if(flag==2){
			sb.append(""
				+ "				+ "xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" "
				+ "xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">"
				+ "	"
				+ ""
				+ "");
		}
		return sb.toString();
	}


	/**
	 * 外部可访问的方法，获得汇率数据
	 */
	public void getExchangeRate(){
		for(int i=0; i			if(ExchangeRateXML.getInstance().createExchangeRateXMLFile("ExRate.xml")){
				break;
			}
		}
		getExchangeRateDataFromXMLFile("ExRate.xml");
	}
}

这个链接中有一个简单的webservice例子，是获取天气预报的：[url]http://qinshuwei.com/webservic.html[/url]