手把手教你用 SpringBoot 开发微信公众号后台

@GetMapping("/verify_wx_token")
public void login(HttpServletRequest request, HttpServletResponse response) throws UnsupportedEncodingException {
    request.setCharacterEncoding("UTF-8");
    String signature = request.getParameter("signature");
    String timestamp = request.getParameter("timestamp");
    String nonce = request.getParameter("nonce");
    String echostr = request.getParameter("echostr");
    PrintWriter out = null;
    try {
        out = response.getWriter();
        if (CheckUtil.checkSignature(signature, timestamp, nonce)) {
            out.write(echostr);
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        out.close();
    }
}

public class CheckUtil {
    private static final String token = "123456";
    public static boolean checkSignature(String signature, String timestamp, String nonce) {
        String[] str = new String[]{token, timestamp, nonce};
        //排序
        Arrays.sort(str);
        //拼接字符串
        StringBuffer buffer = new StringBuffer();
        for (int i = 0; i < str.length; i++) {
            buffer.append(str[i]);
        }
        //进行sha1加密
        String temp = SHA1.encode(buffer.toString());
        //与微信提供的signature进行匹对
        return signature.equals(temp);
    }
}
public class SHA1 {
    private static final char[] HEX_DIGITS = {'0', '1', '2', '3', '4', '5',
            '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
    private static String getFormattedText(byte[] bytes) {
        int len = bytes.length;
        StringBuilder buf = new StringBuilder(len * 2);
        for (int j = 0; j < len; j++) {
            buf.append(HEX_DIGITS[(bytes[j] >> 4) & 0x0f]);
            buf.append(HEX_DIGITS[bytes[j] & 0x0f]);
        }
        return buf.toString();
    }
    public static String encode(String str) {
        if (str == null) {
            return null;
        }
        try {
            MessageDigest messageDigest = MessageDigest.getInstance("SHA1");
            messageDigest.update(str.getBytes());
            return getFormattedText(messageDigest.digest());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

<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>

@PostMapping("/verify_wx_token")
public void handler(HttpServletRequest request, HttpServletResponse response) throws Exception {
    request.setCharacterEncoding("UTF-8");
    response.setCharacterEncoding("UTF-8");
    PrintWriter out = response.getWriter();
    Map<String, String> parseXml = MessageUtil.parseXml(request);
    String msgType = parseXml.get("MsgType");
    String content = parseXml.get("Content");
    String fromusername = parseXml.get("FromUserName");
    String tousername = parseXml.get("ToUserName");
    System.out.println(msgType);
    System.out.println(content);
    System.out.println(fromusername);
    System.out.println(tousername);
}
public static Map<String, String> parseXml(HttpServletRequest request) throws Exception {
    Map<String, String> map = new HashMap<String, String>();
    InputStream inputStream = request.getInputStream();
    SAXReader reader = new SAXReader();
    Document document = reader.read(inputStream);
    Element root = document.getRootElement();
    List<Element> elementList = root.elements();
    for (Element e : elementList)
        map.put(e.getName(), e.getText());
    inputStream.close();
    inputStream = null;
    return map;
}

public class BaseMessage {
    private String ToUserName;
    private String FromUserName;
    private long CreateTime;
    private String MsgType;
    private long MsgId;
    //省略 getter/setter
}

public class TextMessage extends BaseMessage {
    private String Content;
    //省略 getter/setter
}

/**
 * 返回消息类型：文本
 */
public static final String RESP_MESSAGE_TYPE_TEXT = "text";
/**
 * 返回消息类型：音乐
 */
public static final String RESP_MESSAGE_TYPE_MUSIC = "music";
/**
 * 返回消息类型：图文
 */
public static final String RESP_MESSAGE_TYPE_NEWS = "news";
/**
 * 返回消息类型：图片
 */
public static final String RESP_MESSAGE_TYPE_Image = "image";
/**
 * 返回消息类型：语音
 */
public static final String RESP_MESSAGE_TYPE_Voice = "voice";
/**
 * 返回消息类型：视频
 */
public static final String RESP_MESSAGE_TYPE_Video = "video";
/**
 * 请求消息类型：文本
 */
public static final String REQ_MESSAGE_TYPE_TEXT = "text";
/**
 * 请求消息类型：图片
 */
public static final String REQ_MESSAGE_TYPE_IMAGE = "image";
/**
 * 请求消息类型：链接
 */
public static final String REQ_MESSAGE_TYPE_LINK = "link";
/**
 * 请求消息类型：地理位置
 */
public static final String REQ_MESSAGE_TYPE_LOCATION = "location";
/**
 * 请求消息类型：音频
 */
public static final String REQ_MESSAGE_TYPE_VOICE = "voice";
/**
 * 请求消息类型：视频
 */
public static final String REQ_MESSAGE_TYPE_VIDEO = "video";
/**
 * 请求消息类型：推送
 */
public static final String REQ_MESSAGE_TYPE_EVENT = "event";
/**
 * 事件类型：subscribe(订阅)
 */
public static final String EVENT_TYPE_SUBSCRIBE = "subscribe";
/**
 * 事件类型：unsubscribe(取消订阅)
 */
public static final String EVENT_TYPE_UNSUBSCRIBE = "unsubscribe";
/**
 * 事件类型：CLICK(自定义菜单点击事件)
 */
public static final String EVENT_TYPE_CLICK = "CLICK";
/**
 * 事件类型：VIEW(自定义菜单 URl 视图)
 */
public static final String EVENT_TYPE_VIEW = "VIEW";
/**
 * 事件类型：LOCATION(上报地理位置事件)
 */
public static final String EVENT_TYPE_LOCATION = "LOCATION";
/**
 * 事件类型：LOCATION(上报地理位置事件)
 */
public static final String EVENT_TYPE_SCAN = "SCAN";

public static String textMessageToXml(TextMessage textMessage) {
    xstream.alias("xml", textMessage.getClass());
    return xstream.toXML(textMessage);
}
private static XStream xstream = new XStream(new XppDriver() {
    public HierarchicalStreamWriter createWriter(Writer out) {
        return new PrettyPrintWriter(out) {
            boolean cdata = true;
            @SuppressWarnings("rawtypes")
            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);
                }
            }
        };
    }
});

public class MessageDispatcher {
    public static String processMessage(Map<String, String> map) {
        String openid = map.get("FromUserName"); //用户 openid
        String mpid = map.get("ToUserName");   //公众号原始 ID
        if (map.get("MsgType").equals(MessageUtil.REQ_MESSAGE_TYPE_TEXT)) { 
            //普通文本消息
            TextMessage txtmsg = new TextMessage();
            txtmsg.setToUserName(openid);
            txtmsg.setFromUserName(mpid);
            txtmsg.setCreateTime(new Date().getTime());
            txtmsg.setMsgType(MessageUtil.RESP_MESSAGE_TYPE_TEXT);
            txtmsg.setContent("这是返回消息");
            return MessageUtil.textMessageToXml(txtmsg);
        }
        return null;
    }
    public String processEvent(Map<String, String> map) {
        //在这里处理事件
    }
}

@PostMapping(value = "/verify_wx_token",produces = "application/xml;charset=utf-8")
public String handler(HttpServletRequest request, HttpServletResponse response) throws Exception {
    request.setCharacterEncoding("UTF-8");
    Map<String, String> map = MessageUtil.parseXml(request);
    String msgType = map.get("MsgType");
    if (MessageUtil.REQ_MESSAGE_TYPE_EVENT.equals(msgType)) {
        return messageDispatcher.processEvent(map);
    }else{
        return messageDispatcher.processMessage(map);
    }
}