1. java 二維碼生成工具類

import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import com.pdatao.api.controller.file.FileController;
import com.pdatao.api.error.CommunityException;
import org.apache.commons.io.IOUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.multipart.MultipartFile;import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.StandardCharsets;@Component
public class MpQrCodeUtil {@ResourceFileController fileController;@Value("${mp.wechat.appid}")private String mpAppId;@Value("${mp.wechat.secret}")private String mpSecretId;@Value("${qrcode.pageHome}")private String pageHome;@Value("${spring.profiles.active:}")private String activeProfile;private static final String API_GET_TOKEN = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=%s&secret=%s";private static final String API_GET_QR_CODE = "https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=%s";private static String cachedToken = null;private static long tokenExpireTime = 0;public String getMpQRCode(Long orderId, HttpServletRequest request) throws Exception {String scenes = "id=" + orderId + "&v=1";String envVersion = "";if ("prod-plus".equals(activeProfile)) {envVersion = "release";}return this.getQRCodeWeb(scenes,envVersion,orderId,request);}public String getQRCodeWeb(String scenes, String envVersion, Long orderId, HttpServletRequest request) throws Exception {String accessToken = getToken(mpAppId, mpSecretId);return getQRCode(accessToken, scenes, envVersion, orderId, request);}public static String getToken(String appId, String appSecret) throws Exception {// 1. 檢查緩存是否有效if (cachedToken != null && System.currentTimeMillis() < tokenExpireTime) {return cachedToken;}HttpURLConnection conn = null;try {String url = String.format(API_GET_TOKEN, appId, appSecret);conn = (HttpURLConnection) new URL(url).openConnection();conn.setConnectTimeout(5000);conn.setReadTimeout(5000);conn.setRequestMethod("GET");int statusCode = conn.getResponseCode();if (statusCode != 200) {// 讀取錯誤流String errorJson = IOUtils.toString(conn.getErrorStream(), StandardCharsets.UTF_8);throw new CommunityException("微信接口錯誤: " + errorJson);}JSONObject result = new JSONObject(IOUtils.toString(conn.getInputStream(), StandardCharsets.UTF_8));cachedToken = result.getStr("access_token");long expiresIn = result.getLong("expires_in") * 1000; // 轉為毫秒tokenExpireTime = System.currentTimeMillis() + expiresIn - 600_000;return cachedToken;} finally {if (conn != null) conn.disconnect();}}public String getQRCode(String accessToken, String scenes, String envVersion, Long orderId, HttpServletRequest request) throws Exception {HttpURLConnection httpURLConnection = null;try {URL url = new URL(String.format(API_GET_QR_CODE, accessToken));httpURLConnection = (HttpURLConnection) url.openConnection();httpURLConnection.setRequestMethod("POST");// 提交模式// 發送POST請求必須設置如下兩行httpURLConnection.setDoOutput(true);httpURLConnection.setDoInput(true);// 發送請求參數com.alibaba.fastjson.JSONObject paramJson = new com.alibaba.fastjson.JSONObject();paramJson.put("scene", scenes);paramJson.put("page", pageHome);paramJson.put("env_version", StrUtil.isNotEmpty(envVersion) ? envVersion : "trial");paramJson.put("check_path", false);try (PrintWriter printWriter = new PrintWriter(httpURLConnection.getOutputStream())) {printWriter.write(paramJson.toString());printWriter.flush();}// 檢查響應碼int responseCode = httpURLConnection.getResponseCode();if (responseCode != HttpURLConnection.HTTP_OK) {cachedToken = null;throw new CommunityException("生成二維碼失敗：HTTP錯誤碼 " + responseCode);}// 檢查內容類型String contentType = httpURLConnection.getContentType();if (contentType == null || !contentType.startsWith("image/")) {cachedToken = null;throw new CommunityException("生成二維碼失敗：接口返回非圖片數據（" +  (contentType != null ? contentType : "未知內容類型") + "）");}try (InputStream is = httpURLConnection.getInputStream(); ByteArrayOutputStream baos = new ByteArrayOutputStream();) {byte[] buffer = new byte[1024];int len = -1;while ((len = is.read(buffer)) != -1) {baos.write(buffer, 0, len);}byte[] imageData = baos.toByteArray();// 簡單驗證是否是有效圖片（可選）if (imageData.length == 0) {cachedToken = null;throw new CommunityException("生成二維碼失敗：返回空圖片數據");}MultipartFile multipartFile = new ByteArrayMultipartFile(orderId + "_mpqrcode",          // 表單字段名orderId + "_mpqrcode.png",      // 文件名"image/png",                  // 內容類型imageData                  // 內容);com.alibaba.fastjson.JSONObject json = fileController.upload(multipartFile,request);if (json == null || !json.containsKey("url")) {throw new CommunityException("上傳圖片失敗：響應數據異常");}return json.getString("url");}} catch (Exception e) {e.printStackTrace();throw new CommunityException("生成二維碼失敗："+e.getMessage());} finally {if (httpURLConnection != null) {httpURLConnection.disconnect();}}}}

2. 部分可自行調整的代碼解釋

FileController： 我自己的上傳圖片到服務器的類

mpAppId：? 小程序appid

mpSecretId： 小程序?SecretId

pageHome： 要跳轉的小程序的頁面地址（例如： ‘pages/userInfo/userInfoHome’）

activeProfile： 我自己的判斷當前運行環境的配置（可以忽略）

@Resource
FileController fileController;@Value("${mp.wechat.appid}")
private String mpAppId;
@Value("${mp.wechat.secret}")
private String mpSecretId;@Value("${qrcode.pageHome}")
private String pageHome;
@Value("${spring.profiles.active:}")
private String activeProfile;

getMpQRCode 外部調用的方法，自定義自己需要傳入什么值

Long orderId ： 這個是我為了生成二維碼路徑時攜帶的參數

HttpServletRequest request： 這個參數，和二維碼生成邏輯沒有任何關系，我這里使用只是因為上傳圖片的地方需要這個值，這個比較冗余

scenes： 定義頁面地址攜帶什么參數

if ("prod-plus".equals(activeProfile)) {envVersion = "release";
}      這個是為了判斷生成什么環境的二維碼圖片（正式版/ 體驗版） 

public String getMpQRCode(Long orderId, HttpServletRequest request) throws Exception {String scenes = "id=" + orderId + "&v=1";String envVersion = "";if ("prod-plus".equals(activeProfile)) {envVersion = "release";}return this.getQRCodeWeb(scenes,envVersion,orderId,request);
}

imageData ： 這個就是生成的二維碼圖片信息

下面的其他信息，都是為了把這個圖片的信息，上傳到自己項目中保存，最終返回圖片地址

byte[] imageData = baos.toByteArray();// 簡單驗證是否是有效圖片（可選）
if (imageData.length == 0) {throw new CommunityException("生成核銷二維碼失敗：返回空圖片數據");
}MultipartFile multipartFile = new ByteArrayMultipartFile(orderId + "_mpqrcode",          // 表單字段名orderId + "_mpqrcode.png",      // 文件名"image/png",                  // 內容類型imageData                  // 內容
);
com.alibaba.fastjson.JSONObject json = fileController.upload(multipartFile,request);
if (json == null || !json.containsKey("url")) {throw new CommunityException("上傳二維碼失敗：響應數據異常");
}
return json.getString("url");

3.小程序中獲取攜帶的參數

以我上述的參數為例：（微信小程序使用的 uniapp）

onLoad(option) {if (option.scene) {const scene = decodeURIComponent(option.scene);const params = this.parseSceneParams(scene);console.log(params.id)console.log(params.v)}},methods: {parseSceneParams(scene) {const params = {};if (!scene) return params;const pairs = scene.split('&');pairs.forEach(pair => {const [key, value] = pair.split('=');if (key) params[key] = value;});return params;},
}