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This article introduces the knowledge of "how to develop the backstage of Wechat official account by spring boot". Many people will encounter this dilemma in the operation of actual cases, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Realization idea

The implementation principle of the reply password to obtain the video link is very simple, to put it bluntly, it is just a data query operation, the reply password is the query keyword, and the reply content is the query result. The principle is very simple.

This is how people reply to keywords in the backstage of official account. So what is the delivery process of this message? Let's take a look at the following picture:

Let me explain this picture to you a little bit:

First of all, the character javaboy4096 is sent to the Wechat server from the official account, and then the Wechat server will forward the javaboy4096 to my own server. After I receive the character javaboy4096, I will query the database and return the query results in accordance with the XML format required by Tencent. The Wechat server sends the information received from my server back to Wechat, so the friends will see the return result.

This is the general process.

Next, let's take a look at the implementation details.

3. Backstage configuration of official account

The first step in development is for Wechat servers to verify that our own servers are effective.

First, after we log in to the official website of Wechat public platform, on the "Development-basic Settings" page of the official website of the public platform, check the agreement to become a developer, and then click the "modify configuration" button to fill in:

Server address (URL) TokenEncodingAESKey

After the URL is configured here, we need to develop two interfaces for this URL, one is the interface of GET request, which is used to verify the validity of the server, and the other is the interface of POST request, which is used to receive messages sent by Wechat server. In other words, messages from Wechat servers are sent to me through POST requests.

The Token can be entered by the developer as a signature (the Token is compared with the Token contained in the API URL to verify the security).

EncodingAESKey is manually filled in or randomly generated by developers and will be used as the encryption and decryption key of the message body.

At the same time, developers can choose message encryption and decryption methods: plaintext mode, compatibility mode and security mode. The plaintext mode is that our own server receives a clear text string from the Wechat server, which can be read and parsed directly, while the security mode is that we receive an encrypted message from the Wechat server, which needs to be parsed manually before we can use it.

4. Development

After the background configuration of the official account is complete, we can write code next.

4.1 Server validity check

Let's first create a normal Spring Boot project, and introduce spring-boot-starter-web dependency when creating the project. After the project is successfully created, we create a Controller and add the following APIs:

@ 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 ()

}

}

With regard to this code, I will explain as follows:

First, the four parameters signature, timestamp, nonce and echostr sent by Wechat server are obtained through the request.getParameter method. Among these four parameters: signature represents Wechat encrypted signature, signature combines the token parameter entered by the developer with the timestamp parameter and nonce parameter in the request, timestamp represents time stamp, nonce represents random number, and echostr represents a random string. The developer verifies the request by verifying the signature. If it is confirmed that the GET request is from Wechat server and the echostr parameter content is returned as is, the connection takes effect and becomes a success for the developer, otherwise the connection fails. The specific check is the CheckUtil.checkSignature method here. In this method, the three parameters token, timestamp and nonce are sorted in lexicographic order, then the three parameter strings are concatenated into a string for sha1 encryption, and finally the encrypted string can be compared with signature to identify the origin of the request from Wechat.

The verification code is as follows:

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}

/ / sort

Arrays.sort (str)

/ / concatenate strings

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)

}

}

}

OK, after completion, our verification interface will be considered as completed. Next, you can develop a message receiving interface.

4.2 message receiving interface

Next, let's develop the message receiving interface. The message receiving interface is the same as the above server verification interface address, which is the address we configured in the official account background at the beginning. Except that the message receiver interface is an POST request.

When I configured in the official account background, the message encryption and decryption mode chose plaintext mode, so that the messages I received in the background can be processed directly. The format of the plain text message sent to me by Wechat server is as follows:

1348831860

1234567890123456

These parameters mean the following:

When we see this, we probably have a good idea. When we receive the message from Wechat server, we will parse the XML, extract the information we need, do the relevant query operation, and then return the results to Wechat server.

Let's start with a simple one. We will parse and print out the received messages:

@ 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 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 parseXml (HttpServletRequest request) throws Exception {

Map map = new HashMap ()

InputStream inputStream = request.getInputStream ()

SAXReader reader = new SAXReader ()

Document document = reader.read (inputStream)

Element root = document.getRootElement ()

List elementList = root.elements ()

For (Element e: elementList)

Map.put (e.getName (), e.getText ())

InputStream.close ()

InputStream = null

Return map

}

As you can see, it is actually some regular code, which is not difficult.

After doing this, we pack the project into a jar package and deploy it on the server. After launching successfully, make sure that there is no problem with the background configuration of Wechat, then we can send a message on the official account so that our own server will print out the information of the message just now.

5. Message classification

Before we discuss how to reply to Wechat servers, we need to understand the main types of messages sent by Wechat servers and the types of messages we reply to Wechat.

As you know above, there is a MsgType field in the xml message sent by Wechat, which is used to mark the type of message. This type can mark whether the message is a normal message, an event message, a graphic message, and so on.

Ordinary news mainly refers to:

Text message, picture message, voice message, video message, video message, address, location message, link message

Different message types correspond to different MsgType. Here, I will take ordinary messages as an example, as follows:

Message type MsgType text message text picture message image voice message voice video message video small video message shortvideo address location message location link message link

We must not think that different types of messages have the same format, but in fact they are different. That is to say, messages with MsgType for text and messages with MsgType for image, the message sent to us by Wechat server is different. This brings a problem is that I cannot use a Bean to receive different types of data, so here we usually use Map to receive.

This is the reception of the message. in addition to the reception of the message, there is also a reply to a message. there are also many types of messages we reply to, such as ordinary messages, picture messages, voice messages, and so on. different reply messages can be encapsulated accordingly. Because different return message instances also have some common properties, such as who sent the message, message type, message id, etc., we can define these common properties as a parent class, and then different messages inherit the parent class.

6. Returns the message type definition

First, let's define a common message type:

Public class BaseMessage {

Private String ToUserName

Private String FromUserName

Private long CreateTime

Private String MsgType

Private long MsgId

/ / omit getter/setter

}

Here:

ToUserName indicates the developer's WeChat account FromUserName represents the sender account (user's OpenID) the creation time of the CreateTime message MsgType indicates the type of message MsgId represents the message id

This is our basic message type, that is, the message we return to the user, no matter what type of message it is, has these basic properties. Then on this basis, we expand the text message, picture message and so on.

Let's take a look at the definition of a text message:

Public class TextMessage extends BaseMessage {

Private String Content

/ / omit getter/setter

}

The text message has an additional Content attribute on top of the previous message, so the text message inherits from BaseMessage, and an additional Content attribute is added.

Other message types have similar definitions, so I won't enumerate them one by one. As for the format of other messages, please refer to Wechat Open documents (http://1t.click/aPXK).

7. Return message generation

After the Bean definition of the message type is complete, the next step is to generate the entity class into XML.

First, let's define a message utility class to enumerate common message types:

/ * *

* return message type: text

, /

Public static final String RESP_MESSAGE_TYPE_TEXT = "text"

/ * *

* return message type: music

, /

Public static final String RESP_MESSAGE_TYPE_MUSIC = "music"

/ * *

* return message type: picture and text

, /

Public static final String RESP_MESSAGE_TYPE_NEWS = "news"

/ * *

* return message type: picture

, /

Public static final String RESP_MESSAGE_TYPE_Image = "image"

/ * *

* return message type: voice

, /

Public static final String RESP_MESSAGE_TYPE_Voice = "voice"

/ * *

* return message type: video

, /

Public static final String RESP_MESSAGE_TYPE_Video = "video"

/ * *

* request message type: text

, /

Public static final String REQ_MESSAGE_TYPE_TEXT = "text"

/ * *

* request message type: picture

, /

Public static final String REQ_MESSAGE_TYPE_IMAGE = "image"

/ * *

* request message type: link

, /

Public static final String REQ_MESSAGE_TYPE_LINK = "link"

/ * *

* request message type: geographical location

, /

Public static final String REQ_MESSAGE_TYPE_LOCATION = "location"

/ * *

* request message type: audio

, /

Public static final String REQ_MESSAGE_TYPE_VOICE = "voice"

/ * *

* request message type: video

, /

Public static final String REQ_MESSAGE_TYPE_VIDEO = "video"

/ * *

* request message type: push

, /

Public static final String REQ_MESSAGE_TYPE_EVENT = "event"

/ * *

* event type: subscribe (subscription)

, /

Public static final String EVENT_TYPE_SUBSCRIBE = "subscribe"

/ * *

* event type: unsubscribe (unsubscribe)

, /

Public static final String EVENT_TYPE_UNSUBSCRIBE = "unsubscribe"

/ * *

* event type: CLICK (Custom menu Click event)

, /

Public static final String EVENT_TYPE_CLICK = "CLICK"

/ * *

* event type: VIEW (custom menu URl view)

, /

Public static final String EVENT_TYPE_VIEW = "VIEW"

/ * *

* event type: LOCATION (reporting geolocation events)

, /

Public static final String EVENT_TYPE_LOCATION = "LOCATION"

/ * *

* event type: LOCATION (reporting geolocation events)

, /

Public static final String EVENT_TYPE_SCAN = "SCAN"

Note the definition of the message type here. The message type that begins with RESP indicates the returned message type, and the REQ indicates the message type sent by the Wechat server. Then define two more methods in this utility class to convert the returned object to XML:

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 ("")

} else {

Writer.write (text)

}

}

}

}

});

The textMessageToXML method is used to convert the TextMessage object into XML and return it to the Wechat server. Similar methods also need to define imageMessageToXml, voiceMessageToXml, etc., but they are all defined in a similar way, so I won't list them one by one.

8. Return to message distribution

As there may be a variety of situations in the messages sent by users, we need to classify and deal with them, which involves the distribution of return messages. So I define another utility class that returns message distribution here, as follows:

Public class MessageDispatcher {

Public static String processMessage (Map map) {

String openid = map.get ("FromUserName"); / / user openid

String mpid = map.get ("ToUserName"); / / official account original ID

If (map.get ("MsgType") .equals (MessageUtil.REQ_MESSAGE_TYPE_TEXT)) {

/ / plain text message

TextMessage txtmsg = new TextMessage ()

Txtmsg.setToUserName (openid)

Txtmsg.setFromUserName (mpid)

Txtmsg.setCreateTime (new Date () .getTime ())

Txtmsg.setMsgType (MessageUtil.RESP_MESSAGE_TYPE_TEXT)

Txtmsg.setContent ("this is the return message")

Return MessageUtil.textMessageToXml (txtmsg)

}

Return null

}

Public String processEvent (Map map) {

/ / handle events here

}

}

Here we can also add a few more elseif to determine different message types. I have only plain text messages here, so one if is enough.

In fact, I need to query the data according to the Content sent from Wechat server, and return the query result. I believe everyone can handle the database query, so I won't repeat it here.

Finally, the method is called in the message receiving Controller, as follows:

@ 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 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)

}

}

In Controller, we first determine whether the message is an event, if it is an event, enter the event processing channel, if not, enter the message processing channel.

This is the end of the content of "how to develop the backstage of Wechat official account by spring boot". Thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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