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java生成微信小程序二维码

二维码Java

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appidmap.put("secret", "要链接小程序的secret"); //改成自己的secretString 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 。


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