在JAVA中先編寫url請求的工具類:UrlUtil,代碼如下:
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 發送POST方法的請求
*
* @param url
* 發送請求的 URL
* @param param
* 請求參數
* @return 所代表遠程資源的響應結果
*/
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);
// 打開和URL之間的連接
URLConnection conn = realUrl.openConnection();
// 設置通用的請求屬性
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)");
// 發送POST請求必須設置如下兩行
conn.setDoOutput(true);
conn.setDoInput(true);
// 獲取URLConnection對象對應的輸出流
out = new PrintWriter(conn.getOutputStream());
// 發送請求參數
out.print(param);
// flush輸出流的緩沖
out.flush();
// 定義BufferedReader輸入流來讀取URL的響應
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塊來關閉輸出流、輸入流
finally {
try {
if (out != null) {
out.close();
}
if (in != null) {
in.close();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
return result;
}
}
然后編寫獲取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", "要鏈接到小程序的id");// 改成自己的appid
map.put("secret", "要鏈接小程序的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;
}
}
接下來獲取二維碼的方法,為了測試,我將生成二維碼流打印到了自己本地的D盤。看看能不能掃描成功,答案是可以:
//sceneStr:鏈接到改小程序界面所要的參數
//accessToken:上一個方法中所生產的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("調用小程序生成微信永久小程序碼URL接口返回結果:" + 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("調用異常");
} 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方法測試:
public static void main(String[] args) {
String token = getToken();
getminiqrQr("1023", token);
}
獲取token,二維碼的方法,以及測試的main方法,放到一個類中即可,復制可運行,但得導入相應的jar包。
這就生成二維碼了,具體獲取token.二維碼的參數,可以到小程序官網進行查看,此測試只填寫了必須的參數。
(小程序獲取二維碼官網:https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/access-token/auth.getAccessToken.html
獲取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






