Java获取小程序码示例（三种小程序码）

首先我们可以看到官方文档上是有三种码的 获取小程序码

这里特别要注意的是第一种和第三种是有数量限制的，所以大家生成的时候记得保存，也不要一直瞎生成

还有一点要注意的是第一种和第二种是太阳码

第三种是方形码

好了直接上代码
这里要注意，它请求成功返回的是一个 base64 的图片流，但是失败返回的是JSON字符串，我这里没有处理请求失败的问题

package com.sakura.user.utils;import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.sakura.common.exception.BusinessException;
import com.sakura.common.redis.RedisUtil;
import com.sakura.common.tool.HttpsRequestUtil;
import com.sakura.common.tool.StringUtil;
import com.sakura.user.param.GetAppCodeParam;
import com.sakura.user.vo.wx.WxAccessTokenVo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;/*** @author Sakura* @date 2024/8/22 11:04* 微信小程序工具类*/
@Component
@Slf4j
public class WxAppUtil {@Value("${wx.app.appid}")private String appid;@Value("${wx.app.secret}")private String secret;// 获取授权tokenprivate static final String GET_TOKEN = "https://api.weixin.qq.com/cgi-bin/token";private static final String WX_APP_ACCESS_TOKEN = "wx_app_access_token";// 获取小程序码URLprivate static final String GET_APP_CODE_URL = "https://api.weixin.qq.com/wxa/getwxacode";// 获取不受限制的小程序码private static final String GET_UNLIMITED_APP_CODE_URL = "https://api.weixin.qq.com/wxa/getwxacodeunlimit";private static final String GET_APP_QR_CODE_URL = "https://api.weixin.qq.com/cgi-bin/wxaapp/createwxaqrcode";@Autowiredprivate RedisUtil redisUtil;// 获取授权凭证public String getAccessToken() {// 优先从Redis获取，没有再调接口// 如果Redis里面有则直接取Redis里面的if (redisUtil.hasKey(WX_APP_ACCESS_TOKEN)) {log.info(redisUtil.get(WX_APP_ACCESS_TOKEN).toString());return redisUtil.get(WX_APP_ACCESS_TOKEN).toString();}// 拼接请求参数StringBuilder strUrl = new StringBuilder();strUrl.append(GET_TOKEN).append("?grant_type=client_credential").append("&appid=").append(appid).append("&secret=").append(secret);try {String resultStr = HttpsRequestUtil.sendGetRequest(strUrl.toString());log.info("【微信小程序获取授权凭证】：返回结果：" + resultStr);WxAccessTokenVo wxAccessTokenVo = JSON.parseObject(resultStr, WxAccessTokenVo.class);if (StringUtil.isBlank(wxAccessTokenVo.getAccess_token())) {throw new BusinessException("微信小程序获取授权凭证异常");}//官方 access_token expires_in 为 2个小时, 这里设置 100分钟redisUtil.set(WX_APP_ACCESS_TOKEN, wxAccessTokenVo.getAccess_token(), 100 * 60);return wxAccessTokenVo.getAccess_token();} catch (Exception e) {log.info("【微信小程序获取授权凭证】：获取异常：" + e.getMessage());e.printStackTrace();throw new BusinessException("微信小程序获取授权凭证异常");}}// 获取小程序码public byte[] getAppCode(GetAppCodeParam getAppCodeParam) {// 先要获取access_tokenString accessToken = getAccessToken();// 拼接请求参数StringBuilder strUrl = new StringBuilder();strUrl.append(GET_APP_CODE_URL).append("?access_token=").append(accessToken);// 封装请求参数到bodyJSONObject jsonObject = new JSONObject();jsonObject.put("path", getAppCodeParam.getPath());if (StringUtil.isNotBlank(getAppCodeParam.getEnvVersion())) {jsonObject.put("env_version", getAppCodeParam.getEnvVersion());}if (getAppCodeParam.getWidth() != null) {jsonObject.put("width", getAppCodeParam.getWidth());}if (getAppCodeParam.getIsHyaline() != null) {jsonObject.put("is_hyaline", getAppCodeParam.getIsHyaline());}try {return HttpsRequestUtil.sendPostReturnByte(strUrl.toString(), jsonObject.toJSONString());} catch (Exception e) {log.info("【微信小程序获取小程序码】：获取小程序码异常：" + e.getMessage());e.printStackTrace();throw new BusinessException("微信小程序获取小程序码异常");}}// 获取无限制的小程序码public byte[] getUnlimitedAppCode(GetAppCodeParam getAppCodeParam) {// 先要获取access_tokenString accessToken = getAccessToken();// 拼接请求参数StringBuilder strUrl = new StringBuilder();strUrl.append(GET_UNLIMITED_APP_CODE_URL).append("?access_token=").append(accessToken);// 封装请求参数到bodyJSONObject jsonObject = new JSONObject();jsonObject.put("scene", getAppCodeParam.getScene());if (StringUtil.isNotBlank(getAppCodeParam.getPage())) {jsonObject.put("page", getAppCodeParam.getPage());}if (StringUtil.isNotBlank(getAppCodeParam.getEnvVersion())) {jsonObject.put("env_version", getAppCodeParam.getEnvVersion());}if (getAppCodeParam.getWidth() != null) {jsonObject.put("width", getAppCodeParam.getWidth());}if (getAppCodeParam.getIsHyaline() != null) {jsonObject.put("is_hyaline", getAppCodeParam.getIsHyaline());}if (getAppCodeParam.getCheckPath() != null) {jsonObject.put("check_path", getAppCodeParam.getCheckPath());}try {return HttpsRequestUtil.sendPostReturnByte(strUrl.toString(), jsonObject.toJSONString());} catch (Exception e) {log.info("【微信小程序获取不限制小程序码】：获取不限制小程序码异常：" + e.getMessage());e.printStackTrace();throw new BusinessException("微信小程序获取不限制小程序码异常");}}// 获取小程序二维码public byte[] getAppQRCode(GetAppCodeParam getAppCodeParam) {// 先要获取access_tokenString accessToken = getAccessToken();// 拼接请求参数StringBuilder strUrl = new StringBuilder();strUrl.append(GET_APP_QR_CODE_URL).append("?access_token=").append(accessToken);// 封装请求参数到bodyJSONObject jsonObject = new JSONObject();jsonObject.put("path", getAppCodeParam.getPath());if (getAppCodeParam.getWidth() != null) {jsonObject.put("width", getAppCodeParam.getWidth());}try {return HttpsRequestUtil.sendPostReturnByte(strUrl.toString(), jsonObject.toJSONString());} catch (Exception e) {log.info("【微信小程序获取小程序二维码】：获取小程序二维码异常：" + e.getMessage());e.printStackTrace();throw new BusinessException("微信小程序获取小程序二维码异常");}}
}

http 工具类

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;/*** @author Sakura* @date 2024/6/24 17:07*/
public class HttpsRequestUtil {public static String sendPostRequest(String urlString, String jsonInputString) throws IOException {URL url = new URL(urlString);HttpURLConnection connection = (HttpURLConnection) url.openConnection();// 设置请求方法为POSTconnection.setRequestMethod("POST");// 设置请求头connection.setRequestProperty("Content-Type", "application/json");connection.setRequestProperty("Accept", "application/json");// 启用输出流，用于发送请求数据connection.setDoOutput(true);try (OutputStream os = connection.getOutputStream()) {byte[] input = jsonInputString.getBytes("utf-8");os.write(input, 0, input.length);}// 获取响应try (BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream(), "utf-8"))) {StringBuilder response = new StringBuilder();String responseLine;while ((responseLine = br.readLine()) != null) {response.append(responseLine.trim());}return response.toString();} finally {// 关闭连接connection.disconnect();}}public static String sendGetRequest(String urlString) throws IOException {URL url = new URL(urlString);HttpURLConnection connection = (HttpURLConnection) url.openConnection();// 设置请求方法为GETconnection.setRequestMethod("GET");// 设置请求头connection.setRequestProperty("Accept", "application/json");// 获取响应try (BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream(), "utf-8"))) {StringBuilder response = new StringBuilder();String responseLine;while ((responseLine = br.readLine()) != null) {response.append(responseLine.trim());}return response.toString();} finally {// 关闭连接connection.disconnect();}}public static byte[] sendPostReturnByte(String urlString, String jsonInputString) throws IOException {URL url = new URL(urlString);HttpURLConnection connection = (HttpURLConnection) url.openConnection();// 设置请求方法为POSTconnection.setRequestMethod("POST");// 设置请求头connection.setRequestProperty("Content-Type", "application/json");connection.setRequestProperty("Accept", "application/json");// 启用输出流，用于发送请求数据connection.setDoOutput(true);try (OutputStream os = connection.getOutputStream()) {byte[] input = jsonInputString.getBytes("utf-8");os.write(input, 0, input.length);}// 获取响应try (InputStream is = connection.getInputStream()) {ByteArrayOutputStream buffer = new ByteArrayOutputStream();int bytesRead;byte[] data = new byte[1024];while ((bytesRead = is.read(data, 0, data.length)) != -1) {buffer.write(data, 0, bytesRead);}return buffer.toByteArray();} finally {// 关闭连接connection.disconnect();}}}

请求的参数

import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;
import lombok.experimental.Accessors;import javax.validation.constraints.NotNull;
import java.io.Serializable;/*** 获取小程序码参数** @author Sakura* @since 2024-08-26*/
@Data
@Accessors(chain = true)
@ApiModel(value = "获取小程序码参数")
public class GetAppCodeParam implements Serializable {private static final long serialVersionUID = 1L;@ApiModelProperty("类型：1小程序码 2不受限制小程序码 3小程序二维码")@NotNull(message = "小程序码类型不能为空")private Integer type;@ApiModelProperty("type为1.3时必传 扫码进入的小程序页面路径")private String path;@ApiModelProperty("type为1.2时可传 要打开的小程序版本。正式版为 \"release\"，体验版为 \"trial\"，开发版为 \"develop\"。默认是正式版。")private String envVersion;@ApiModelProperty("二维码宽度 默认430，二维码的宽度，单位 px，最小 280px，最大 1280px")private Integer width;@ApiModelProperty("type为2时必传 自定义参数最大32个可见字符 如 a=1")private String scene;@ApiModelProperty("type为2时可传 默认是true，检查page 是否存在，为 true 时 page 必须是已经发布的小程序存在的页面（否则报错）；为 false 时允许小程序未发布或者 page 不存在， 但page 有数量上限（60000个）请勿滥用。")private Boolean checkPath;@ApiModelProperty("type为2时可传 默认是主页，页面 page，例如 pages/index/index，根路径前不要填加 /，不能携带参数（参数请放在scene字段里），如果不填写这个字段，默认跳主页面。scancode_time为系统保留参数，不允许配置")private String page;@ApiModelProperty("type为1.2时可传 默认值false；是否需要透明底色，为 true 时，生成透明底色的小程序码")private Boolean isHyaline;}

还有因为返回的是个流，所以我们还需要把它转成图片保存起来，这里大家可以上传到云存储也可就放在服务器上，我这里就是放在服务器上的，在本地项目或者服务器 jar 包目录下 “./resources/files/appcode”

	@Overridepublic String getAppCode(GetAppCodeParam getAppCodeParam) throws Exception {// 根据类型获取不同二维码byte[] bytes = null;if (getAppCodeParam.getType() == 1) {bytes = wxAppUtil.getAppCode(getAppCodeParam);} else if (getAppCodeParam.getType() == 2) {bytes = wxAppUtil.getUnlimitedAppCode(getAppCodeParam);} else if (getAppCodeParam.getType() == 3) {bytes = wxAppUtil.getAppQRCode(getAppCodeParam);}if (bytes == null || bytes.length < 1) {throw new BusinessException("获取小程序码失败");}// 目标目录String outputDir = "./resources/files/appcode";// 创建目录（如果不存在）File directory = new File(outputDir);if (!directory.exists()) {directory.mkdirs();}// 生成图片文件的完整路径String outputFileName = RandomStringUtils.randomAlphanumeric(32);String outputFilePath = outputDir + "/" + outputFileName + ".png";// 将字节数组写入到图片文件中try (FileOutputStream fos = new FileOutputStream(outputFilePath)) {fos.write(bytes);}return "https://sakura.com/api-wx/appCode/download/" + outputFileName;}

因为图片存在服务器上了，我们还需要下载下来
看不懂的可以看下我另一篇讲什么上传下载文件的 Java实现本地文件上传下载接口示例

 @Overridepublic void download(HttpServletResponse response, String code) throws Exception {File downloadFile = new File("./resources/files/appcode/" + code + ".png");if (!downloadFile.exists() || downloadFile.length() == 0) {throw new BusinessException(500, "文件不存在");}// 确定文件的Content-TypeString mimeType = Files.probeContentType(downloadFile.toPath());if (mimeType == null) {mimeType = "application/octet-stream"; // 默认类型}response.setContentType(mimeType);response.addHeader("Content-Length", String.valueOf(downloadFile.length()));response.addHeader("Content-Disposition", "attachment; filename=\"" + code + ".png\"");try (InputStream is = new FileInputStream(downloadFile);OutputStream os = response.getOutputStream()) {IOUtils.copy(is, os);os.flush(); // 确保数据已写入输出流} catch (IOException e) {log.info("下载图片发生IO异常");e.printStackTrace();throw new BusinessException(500, "文件下载失败");} catch (Exception e) {log.info("下载图片发生异常");e.printStackTrace();throw new BusinessException(500, "文件下载失败");}}

最后，小程序获取 AccessToken 是需要添加白名单的，然后第二种码在小程序没发布的时候 check_path 一定要传 false，默认是 true 会报错的