使用JAVA开发微信公众平台接口

package com.wechat.servlet;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.wechat.utils.EncryptUtil;
import com.wechat.utils.XmlUtil;
public class WeChatServlet extends HttpServlet {
  private static final long serialVersionUID = 1L;
  //微信平台上填的Token和这里需要一致
  public static final String Token = "loveplat";
  /**
   * 微信公众平台验证调用方法
   */
  @Override
  protected void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    String signature = request.getParameter("signature");
    String timestamp = request.getParameter("timestamp");
    String nonce = request.getParameter("nonce");
    String[] ArrTmp = { Token, timestamp, nonce };
    Arrays.sort(ArrTmp);
    StringBuffer sb = new StringBuffer();
    for (int i = 0; i < ArrTmp.length; i++) {
      sb.append(ArrTmp[i]);
    }
    String pwd = EncryptUtil.Encrypt(sb.toString());
    String echostr = request.getParameter("echostr");
    System.out.println("pwd=="+pwd);
    System.out.println("echostr=="+echostr);
    if(pwd.equals(signature)){
      if(!"".equals(echostr) && echostr != null){
        response.getWriter().print(echostr);
      }
    }
  }
  /**
   * 用户向公众平台发信息并自动返回信息
   */
  @Override
  protected void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    StringBuffer sb = new StringBuffer();
    String line;
    Map<String, String> map = null;
    try {
      request.setCharacterEncoding("UTF-8");
      BufferedReader reader = request.getReader();
      while ((line = reader.readLine()) != null) {
        sb.append(line);
      }
      map = XmlUtil.xml2Map(sb.toString());
    } catch (Exception e) {
      e.printStackTrace();
    }
    sb = new StringBuffer();
    sb.append("<xml><ToUserName><![CDATA[").append(
        map.get("xml.FromUserName")).append(
        "]]></ToUserName><FromUserName><![CDATA[").append(
        map.get("xml.ToUserName")).append(
        "]]></FromUserName><CreateTime>").append(
        map.get("xml.CreateTime")).append(
        "</CreateTime><MsgType><![CDATA[text]]></MsgType>").append(
        "<Content><![CDATA[收到");
    sb.append("]]></Content>").append("<FuncFlag>0</FuncFlag></xml>");
    response.setCharacterEncoding("UTF-8");
    System.out.println(sb.toString());
    response.getWriter().print(sb.toString());
  }
  @Override
  public void destroy() {
    super.destroy();
  }
  @Override
  public void init() throws ServletException {
    super.init();
  }
}

package com.wechat.utils;
import java.io.IOException;
import java.io.StringReader;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.jdom.Attribute;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
public class XmlUtil {
  public static Map<String, String> xml2Map(String xmlStr)
      throws JDOMException, IOException {
    Map<String, String> rtnMap = new HashMap<String, String>();
    SAXBuilder builder = new SAXBuilder();
    Document doc = builder.build(new StringReader(xmlStr));
    // 得到根节点
    Element root = doc.getRootElement();
    String rootName = root.getName();
    rtnMap.put("root.name", rootName);
    // 调用递归函数，得到所有最底层元素的名称和值，加入map中
    convert(root, rtnMap, rootName);
    return rtnMap;
  }
  /**
   * 递归函数，找出最下层的节点并加入到map中，由xml2Map方法调用。
   * 
   * @param e
   *           xml 节点，包括根节点
   * @param map
   *            目标map
   * @param lastname
   *            从根节点到上一级节点名称连接的字串
   */
  public static void convert(Element e, Map<String, String> map,
      String lastname) {
    if (e.getAttributes().size() > 0) {
      Iterator it_attr = e.getAttributes().iterator();
      while (it_attr.hasNext()) {
        Attribute attribute = (Attribute) it_attr.next();
        String attrname = attribute.getName();
        String attrvalue = e.getAttributeValue(attrname);
        map.put(lastname + "." + attrname, attrvalue);
      }
    }
    List children = e.getChildren();
    Iterator it = children.iterator();
    while (it.hasNext()) {
      Element child = (Element) it.next();
      String name = lastname + "." + child.getName();
      // 如果有子节点，则递归调用
      if (child.getChildren().size() > 0) {
        convert(child, map, name);
      } else {
        // 如果没有子节点，则把值加入map
        map.put(name, child.getText());
        // 如果该节点有属性，则把所有的属性值也加入map
        if (child.getAttributes().size() > 0) {
          Iterator attr = child.getAttributes().iterator();
          while (attr.hasNext()) {
            Attribute attribute = (Attribute) attr.next();
            String attrname = attribute.getName();
            String attrvalue = child.getAttributeValue(attrname);
            map.put(name + "." + attrname, attrvalue);
          }
        }
      }
    }
  }
}

package com.wechat.utils;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class EncryptUtil {
  public static String Encrypt(String strSrc) {
    MessageDigest md = null;
    String strDes = null;
    byte[] bt = strSrc.getBytes();
    try {
      md = MessageDigest.getInstance("SHA-1");
      md.update(bt);
      strDes = bytes2Hex(md.digest()); //to HexString
    } catch (NoSuchAlgorithmException e) {
      System.out.println("Invalid algorithm.");
      return null;
    }
    return strDes;
  }
  public static String bytes2Hex(byte[] bts) {
    String des = "";
    String tmp = null;
    for (int i = 0; i < bts.length; i++) {
      tmp = (Integer.toHexString(bts[i] & 0xFF));
      if (tmp.length() == 1) {
        des += "0";
      }
      des += tmp;
    }
    return des;
  }
}