【wechat】微信开发——微信验证与处理请求（关注后推送消息）

CoreServlet.java

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

import com.raipeng.wechat.domain.TextMessage;
import com.raipeng.wechat.util.MessageUtil;

@SuppressWarnings("serial")
public class CoreServlet extends HttpServlet {
private static String token = "weixinCourse";

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
String signature = req.getParameter("signature");
String timestamp = req.getParameter("timestamp");
String nonce = req.getParameter("nonce");
String echostr = req.getParameter("echostr");

PrintWriter pw = resp.getWriter();

if(checkSignature(signature, timestamp, nonce)){
pw.print(echostr);
pw.close();
pw = null;
}
}

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
req.setCharacterEncoding("UTF-8");
resp.setCharacterEncoding("UTF-8");
String respMessage = null;
try {
Map<String, String> requestMap = parseXml(req);
String toUserName = requestMap.get("ToUserName");
String fromUserName = requestMap.get("FromUserName");
String createTime = requestMap.get("CreateTime");
String msgType = requestMap.get("MsgType");
if(msgType.equals("event")){
String event = requestMap.get("Event");
if(event.equals("subscribe")){
TextMessage textMessage = new TextMessage();
textMessage.setToUserName(fromUserName);
textMessage.setFromUserName(toUserName);
textMessage.setCreateTime(new Date().getTime());
textMessage.setMsgType("text");
textMessage.setContent("欢迎关注");
respMessage = MessageUtil.textMessageToXml(textMessage);
}
}

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
PrintWriter writer = resp.getWriter();
writer.print(respMessage);
writer.flush();
writer.close();
}

SignUtil.java

/**
* 验证签名
*
* @param signature
* @param timestamp
* @param nonce
* @return
*/
public static boolean checkSignature(String signature, String timestamp, String nonce) {
String[] arr = new String[] { token, timestamp, nonce };
// 将token、timestamp、nonce三个参数进行字典序排序
//数组排序
Arrays.sort(arr);
//String 字符串常量
//StringBuffer 字符串变量（线程安全）
//StringBuilder 字符串变量（非线程安全）
StringBuilder content = new StringBuilder();
for (int i = 0; i < arr.length; i++) {
content.append(arr[i]);
}
//java.security.MessageDigest类用于为应用程序提供信息摘要算法的功能，如 MD5 或 SHA 算法。简单点说就是用于生成散列码。
MessageDigest md = null;
String tmpStr = null;
try {
md = MessageDigest.getInstance("SHA-1");
// 将三个参数字符串拼接成一个字符串进行sha1加密
byte[] digest = md.digest(content.toString().getBytes());
tmpStr = byteToStr(digest);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
content = null;
// 将sha1加密后的字符串可与signature对比，标识该请求来源于微信
return tmpStr != null ? tmpStr.equals(signature.toUpperCase()) : false;
}
/**
* 将字节数组转换为十六进制字符串
*
* @param byteArray
* @return
*/
private static String byteToStr(byte[] byteArray) {
String strDigest = "";
for (int i = 0; i < byteArray.length; i++) {
strDigest += byteToHexStr(byteArray[i]);
}
return strDigest;
}

/**
* 将字节转换为十六进制字符串
*
* @param mByte
* @return
*/
private static String byteToHexStr(byte mByte) {
char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
char[] tempArr = new char[2];
tempArr[0] = Digit[(mByte >>> 4) & 0X0F];
tempArr[1] = Digit[mByte & 0X0F];
String s = new String(tempArr);
return s;
}
}

MessageUtil.java

/**
* 解析微信发来的请求（XML）
*
* @param request
* @return
* @throws Exception
*/
@SuppressWarnings("unchecked")
public static Map<String, String> parseXml(HttpServletRequest request) throws Exception {
// 将解析结果存储在HashMap中
Map<String, String> map = new HashMap<String, String>();

// 从request中取得输入流
InputStream inputStream = request.getInputStream();
// 读取输入流
SAXReader reader = new SAXReader();
Document document = reader.read(inputStream);
// 得到xml根元素
Element root = document.getRootElement();
// 得到根元素的所有子节点
List<Element> elementList = root.elements();

// 遍历所有子节点
for (Element e : elementList)
map.put(e.getName(), e.getText());

// 释放资源
inputStream.close();
inputStream = null;

return map;
}

/**
* 文本消息对象转换成xml
*
* @param textMessage 文本消息对象
* @return xml
*/
public static String textMessageToXml(TextMessage textMessage) {
xstream.alias("xml", textMessage.getClass());
return xstream.toXML(textMessage);
}
/**
* 扩展xstream，使其支持CDATA块
*
* @date 2013-05-19
*/
private static XStream xstream = new XStream(new XppDriver() {
public HierarchicalStreamWriter createWriter(Writer out) {
return new PrettyPrintWriter(out) {
// 对所有xml节点的转换都增加CDATA标记
boolean cdata = true;

@SuppressWarnings("unchecked")
public void startNode(String name, Class clazz) {
super.startNode(name, clazz);
}

protected void writeText(QuickWriter writer, String text) {
if (cdata) {
writer.write("<![CDATA[");
writer.write(text);
writer.write("]]>");
} else {
writer.write(text);
}
}
};
}
});

TextMessage.java

private String ToUserName;
private String FromUserName;
private String MsgType;
private long CreateTime;
private String Content;
public String getToUserName() {
return ToUserName;
}
public void setToUserName(String toUserName) {
ToUserName = toUserName;
}
public String getFromUserName() {
return FromUserName;
}
public void setFromUserName(String fromUserName) {
FromUserName = fromUserName;
}
public String getMsgType() {
return MsgType;
}
public void setMsgType(String msgType) {
MsgType = msgType;
}
public long getCreateTime() {
return CreateTime;
}
public void setCreateTime(long createTime) {
CreateTime = createTime;
}
public String getContent() {
return Content;
}
public void setContent(String content) {
Content = content;
}

web.xml

<servlet>
<servlet-name>coreServlet</servlet-name>
<servlet-class>com.raipeng.wechat.servlet.CoreServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>coreServlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>