在JAVA中先编写url请求的工具类:UrlUtil,代码如下:
package com.sinotrans.agent.basic.service.impl; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintWriter; import java.net.URL; import java.net.URLConnection; import java.util.Iterator; import java.util.Map; public class UrlUtil { /** * 向指定 URL 发送POST方法的请求 * * @param url * 发送请求的 URL * @param param * 请求参数 * @return 所代表远程资源的响应结果 */ public static String sendPost(String url, Map<String, ?> paramMap) { PrintWriter out = null; BufferedReader in = null; String result = ""; String param = ""; Iterator<String> it = paramMap.keySet().iterator(); while (it.hasNext()) { String key = it.next(); param += key + "=" + paramMap.get(key) + "&"; } try { URL realUrl = new URL(url); // 打开和URL之间的连接 URLConnection conn = realUrl.openConnection(); // 设置通用的请求属性 conn.setRequestProperty("accept", "*/*"); conn.setRequestProperty("connection", "Keep-Alive"); conn.setRequestProperty("Accept-Charset", "utf-8"); conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; windows NT 5.1;SV1)"); // 发送POST请求必须设置如下两行 conn.setDoOutput(true); conn.setDoInput(true); // 获取URLConnection对象对应的输出流 out = new PrintWriter(conn.getOutputStream()); // 发送请求参数 out.print(param); // flush输出流的缓冲 out.flush(); // 定义BufferedReader输入流来读取URL的响应 in = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8")); String line; while ((line = in.readLine()) != null) { result += line; } } catch (Exception e) { System.out.println(e); } // 使用finally块来关闭输出流、输入流 finally { try { if (out != null) { out.close(); } if (in != null) { in.close(); } } catch (IOException ex) { ex.printStackTrace(); } } return result; } }
然后编写获取token的方法,
public static String getToken() { try { Map<String, String> map = new LinkedHashMap<String, String>(); map.put("grant_type", "client_credential"); map.put("Appid", "要链接到小程序的id");// 改成自己的appid map.put("secret", "要链接小程序的secret"); //改成自己的secret String rt = UrlUtil.sendPost("https://api.weixin.qq.com/cgi-bin/token", map); JSONObject json = JSONObject.parseobject(rt); if (json.getString("access_token") != null || json.getString("access_token") != "") { System.out.println("token:" + json.getString("access_token")); return json.getString("access_token"); } else { return null; } } catch (Exception e) { e.printStackTrace(); return null; } }
接下来获取二维码的方法,为了测试,我将生成二维码流打印到了自己本地的D盘。看看能不能扫描成功,答案是可以:
//sceneStr:链接到改小程序界面所要的参数 //accessToken:上一个方法中所生产的token public static Map getminiqrQr(String sceneStr, String accessToken) { RestTemplate rest = new RestTemplate(); InputStream inputStream = null; OutputStream outputStream = null; try { String url = "https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=" + accessToken; Map<String, Object> param = new HashMap<>(); param.put("scene", sceneStr); param.put("page", "pages/index/index"); param.put("width", 430); param.put("auto_color", false); MultiValueMap<String, String> headers = new LinkedMultiValueMap<>(); HttpEntity requestEntity = new HttpEntity(param, headers); ResponseEntity<byte[]> entity = rest.exchange(url, HttpMethod.POST, requestEntity, byte[].class, new Object[0]); System.out.println("调用小程序生成微信永久小程序码URL接口返回结果:" + entity.getBody()); byte[] result = entity.getBody(); inputStream = new ByteArrayInputStream(result); File file = new File("D:/Desktop/3.png"); if (!file.exists()) { try { file.createNewFile(); } catch (IOException e) { e.printStackTrace(); } } outputStream = new FileOutputStream(file); int len = 0; byte[] in_b = null; byte[] buf = new byte[1024]; while ((len = inputStream.read(buf, 0, 1024)) != -1) { outputStream.write(buf, 0, len); } outputStream.flush(); } catch (Exception e) { System.out.println("调用异常"); } finally { if (inputStream != null) { try { inputStream.close(); } catch (IOException e) { e.printStackTrace(); } } if (outputStream != null) { try { outputStream.close(); } catch (IOException e) { e.printStackTrace(); } } } return null; }
添加main方法测试:
public static void main(String[] args) { String token = getToken(); getminiqrQr("1023", token); }
获取token,二维码的方法,以及测试的main方法,放到一个类中即可,复制可运行,但得导入相应的jar包。
这就生成二维码了,具体获取token.二维码的参数,可以到小程序官网进行查看,此测试只填写了必须的参数。
(小程序获取二维码官网:https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/access-token/auth.getAccessToken.html
获取token:https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/access-token/auth.getAccessToken.html)
作者:JO安
原文:https://blog.csdn.net/qq_40065816/article/details/91411228