当用户发送消息给公众号时（或某些特定的用户操作引发的事件推送时），会产生一个POST请求，开发者可以在响应包（Get）中返回特定XML结构，来对该消息进行响应（现支持回复文本、图片、图文、语音、视频、音乐）。严格来说，发送被动响应消息其实并不是一种接口，而是对微信服务器发过来消息的一次回复。
各消息类型需要的XML数据包结构参照 微信公众平台开发文档
根据微信公众平台开发者文档描述，编写如下示例代码（java版）供大家参考
首先接收微信服务器POST请求数据, 代码如下:
/**
* 微信公众平台 所有接口入口
*
* @param request
* the request send by the client to the server
* @param response
* the response send by the server to the client
* @throws ServletException
* if an error occurred
* @throws IOException
* if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setCharacterEncoding("UTF-8");
request.setCharacterEncoding("UTF-8");
PrintWriter out = response.getWriter();
try {
InputStream is = request.getInputStream();
PushManage push = new PushManage();
String getXml = push.PushManageXml(is);
out.print(getXml);
} catch (JDOMException e) {
e.printStackTrace();
out.print("");
} catch (Exception e) {
out.print("");
} finally {
if(out!=null) {
out.flush();
out.close();
}
}
}
为了确保正确获取微信服务器的POST数据，首先要成功接入，微信公众平台接入可以参考：微信公众平台接入Java示例代码
根据POST请求的XML数据解析并响应相关信息，代码如下
package cn.wuzhuti.weixin.utils;
import java.io.IOException;
import java.io.InputStream;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;
import org.jdom2.output.XMLOutputter;
public class PushManage {
public String PushManageXml(InputStream is) throws JDOMException {
String returnStr = ""; // 反回Servlet字符串
String toName = ""; // 开发者微信号
String fromName = ""; // 发送方帐号（一个OpenID）
String type = ""; // 请求类型
String con = ""; // 消息内容(接收)
String event = ""; // 自定义按钮事件请求
String eKey = ""; // 事件请求key值
try {
SAXBuilder sax = new SAXBuilder();
Document doc = sax.build(is);
// 获得文件的根元素
Element root = doc.getRootElement();
// 获得根元素的第一级子节点
List list = root.getChildren();
for (int j = 0; j < list.size(); j++) {
// 获得结点
Element first = (Element) list.get(j);
if (first.getName().equals("ToUserName")) {
toName = first.getValue().trim();
} else if (first.getName().equals("FromUserName")) {
fromName = first.getValue().trim();
} else if (first.getName().equals("MsgType")) {
type = first.getValue().trim();
} else if (first.getName().equals("Content")) {
con = first.getValue().trim();
} else if (first.getName().equals("Event")) {
event = first.getValue().trim();
} else if (first.getName().equals("EventKey")) {
eKey = first.getValue().trim();
}
}
} catch (IOException e) {
//异常
}
if (type.equals("event")) { //此为事件
if (event.equals("subscribe")) {// 此为 关注事件
} else if (event.equals("unsubscribe")) { //此为取消关注事件
} else if (event.equals("CLICK")) { //此为 自定义菜单按钮点击事件
// 以下为自定义按钮事件
if (eKey.equals("V1")) { //菜单1
returnStr = getBackXMLTypeText(toName,fromName,"点击了菜单1");
} else if (eKey.equals("V2")) { //菜单2
returnStr = getBackXMLTypeText(toName,fromName,"点击了菜单2");
}
}
} else if (type.equals("text")) { // 此为 文本信息
returnStr = getBackXMLTypeText(toName,fromName,"输入了:"+con);
}
return returnStr;
}
/**
* 编译文本信息
*
* @author xiaowu
* @since 2013-9-27
* @param toName
* @param FromName
* @param content
* @return
*/
private String getBackXMLTypeText(String toName, String fromName,
String content) {
String returnStr = "";
SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHHmmss");
String times = format.format(new Date());
Element rootXML = new Element("xml");
rootXML.addContent(new Element("ToUserName").setText(fromName));
rootXML.addContent(new Element("FromUserName").setText(toName));
rootXML.addContent(new Element("CreateTime").setText(times));
rootXML.addContent(new Element("MsgType").setText("text"));
rootXML.addContent(new Element("Content").setText(content));
Document doc = new Document(rootXML);
XMLOutputter XMLOut = new XMLOutputter();
returnStr = XMLOut.outputString(doc);
return returnStr;
}
/**
* 编译图片信息(单图模式)
*
* @author xiaowu
* @since 2013-9-27
* @param toName
* @param FromName
* @param content
* @return
*/
private String getBackXMLTypeImg(String toName, String fromName,
String title, String content, String url, String pUrl) {
String returnStr = "";
SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHHmmss");
String times = format.format(new Date());
Element rootXML = new Element("xml");
rootXML.addContent(new Element("ToUserName").setText(fromName));
rootXML.addContent(new Element("FromUserName").setText(toName));
rootXML.addContent(new Element("CreateTime").setText(times));
rootXML.addContent(new Element("MsgType").setText("news"));
rootXML.addContent(new Element("ArticleCount").setText("1"));
Element fXML = new Element("Articles");
Element mXML = null;
mXML = new Element("item");
mXML.addContent(new Element("Title").setText(title));
mXML.addContent(new Element("Description").setText(content));
mXML.addContent(new Element("PicUrl").setText(pUrl));
mXML.addContent(new Element("Url").setText(url));
fXML.addContent(mXML);
rootXML.addContent(fXML);
Document doc = new Document(rootXML);
XMLOutputter XMLOut = new XMLOutputter();
returnStr = XMLOut.outputString(doc);
return returnStr;
}
/**
* 编译图片信息(无图模式)
*
* @author xiaowu
* @since 2013-9-27
* @param toName
* @param FromName
* @param content
* @return
*/
private String getBackXMLTypeImg(String toName, String fromName,
String title, String content, String url) {
String returnStr = "";
SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHHmmss");
String times = format.format(new Date());
Element rootXML = new Element("xml");
rootXML.addContent(new Element("ToUserName").setText(fromName));
rootXML.addContent(new Element("FromUserName").setText(toName));
rootXML.addContent(new Element("CreateTime").setText(times));
rootXML.addContent(new Element("MsgType").setText("news"));
rootXML.addContent(new Element("ArticleCount").setText("1"));
Element fXML = new Element("Articles");
Element mXML = null;
//String url = "";
String ss = "";
mXML = new Element("item");
mXML.addContent(new Element("Title").setText(title));
mXML.addContent(new Element("Description").setText(content));
mXML.addContent(new Element("PicUrl").setText(ss));
mXML.addContent(new Element("Url").setText(url));
fXML.addContent(mXML);
rootXML.addContent(fXML);
Document doc = new Document(rootXML);
XMLOutputter XMLOut = new XMLOutputter();
returnStr = XMLOut.outputString(doc);
return returnStr;
}
/**
* 编译音乐信息
*
* @author xiaowu
* @since 2013-9-27
* @param toName
* @param FromName
* @param content
* @return
*/
@SuppressWarnings("unused")
private String getBackXMLTypeMusic(String toName, String fromName,
String content) {
String returnStr = "";
SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHHmmss");
String times = format.format(new Date());
Element rootXML = new Element("xml");
rootXML.addContent(new Element("ToUserName").setText(fromName));
rootXML.addContent(new Element("FromUserName").setText(toName));
rootXML.addContent(new Element("CreateTime").setText(times));
rootXML.addContent(new Element("MsgType").setText("music"));
Element mXML = new Element("Music");
mXML.addContent(new Element("Title").setText("音乐"));
mXML.addContent(new Element("Description").setText("音乐让人心情舒畅！"));
mXML.addContent(new Element("MusicUrl").setText(content));
mXML.addContent(new Element("HQMusicUrl").setText(content));
rootXML.addContent(mXML);
Document doc = new Document(rootXML);
XMLOutputter XMLOut = new XMLOutputter();
returnStr = XMLOut.outputString(doc);
return returnStr;
}
}
xml解析为jdom2
jar包下载：jdom-2.0.5.jar