單例模式解決access_token全局緩存的問題

最初将access_token放到資料庫中，每次擷取時判斷是否過期。可以解決access_token的有效期及通路次數問題。

但是最近需要将公衆号與系統做接口，取消公衆号的資料庫，此時再将access_token等放到系統的資料庫中就不合适了。

受益于薛喜麟的這篇文章：微信處理access_token全局緩存的問題，實作了用單例模式來緩存access_token。

記一下，供以後查用。

mark一下自己的代碼結構：

public class TokenSingleton {

        //緩存accessToken 的Map  ,map中包含 一個accessToken 和 緩存的時間戳

         private Map<String, String> map = new HashMap<>();

         private TokenSingleton() {

         }

         private static TokenSingleton single = null;

         // 靜态工廠方法

         public static TokenSingleton getInstance() {

             if (single == null) {

                 single = new TokenSingleton();

             }

             return single;

         }

         public Map<String, String> getMap() {

             String time = map.get("time");

             String accessToken = map.get("access_token");

             Long nowDate = new Date().getTime();

             if (accessToken != null && time != null && nowDate - Long.parseLong(time) < 6000*1000) {

                 System.out.println("accessToken存在，且沒有逾時 ， 傳回單例");

             } else {

                 System.out.println("accessToken 逾時 ， 或者不存在 ， 重新擷取");

                 String access_token=JSSDKUtil.getAccessToken();

                 //這裡是直接調用微信的API去直接擷取 accessToken 和Jsapi_ticket 擷取

                 String jsapi_token = JSSDKUtil.getTicket(access_token);

                 //"擷取jsapi_token";

                 map.put("time", nowDate + "");

                 map.put("access_token", access_token);

                 map.put("jsapi_token", jsapi_token);

             }

             return map;

         }

         public void setMap(Map<String, String> map) {

             this.map = map;

         }

         public static TokenSingleton getSingle() {

             return single;

         }

         public static void setSingle(TokenSingleton single) {

             TokenSingleton.single = single;

         }

 }

另外一個工具類JSSDKUtil.java截取了部分:

public static String getSignature(String accessToken,String jsapi_ticket,String noncestr,String timestamp,String url){

        System.out.println("accessToken:"+accessToken+"\njsapi_ticket:"+jsapi_ticket+"\n時間戳："+timestamp+"\n随機字元串："+noncestr+"\nURL："+url);  

        //5、将參數排序并拼接字元串  

        String str = "jsapi_ticket="+jsapi_ticket+"&noncestr="+noncestr+"&timestamp="+timestamp+"&url="+url;  

        //6、将字元串進行sha1加密  

        String signature =SHA1(str);  

        System.out.println("參數："+str+"\n簽名："+signature);

        return signature;

    }

    public static String getAccessToken() {  

        String wx_appid = getProperties("wx_appid");

        String wx_appsecret = getProperties("wx_appsecret");

        String access_token = "";  

        String grant_type = "client_credential";//擷取access_token填寫client_credential   

        String AppId=wx_appid;//第三方使用者唯一憑證  

        String secret=wx_appsecret;//第三方使用者唯一憑證密鑰，即appsecret   

        //這個url連結位址和參數皆不能變  

        String url = "https://api.weixin.qq.com/cgi-bin/token?grant_type="+grant_type+"&appid="+AppId+"&secret="+secret;  

        try {  

            URL urlGet = new URL(url);  

            HttpURLConnection http = (HttpURLConnection) urlGet.openConnection();  

            http.setRequestMethod("GET"); // 必須是get方式請求  

            http.setRequestProperty("Content-Type","application/x-www-form-urlencoded");  

            http.setDoOutput(true);  

            http.setDoInput(true);  

            System.setProperty("sun.net.client.defaultConnectTimeout", "30000");// 連接配接逾時30秒  

            System.setProperty("sun.net.client.defaultReadTimeout", "30000"); // 讀取逾時30秒  

            http.connect();  

            InputStream is = http.getInputStream();  

            int size = is.available();  

            byte[] jsonBytes = new byte[size];  

            is.read(jsonBytes);  

            String message = new String(jsonBytes, "UTF-8");  

            JSONObject demoJson = JSONObject.fromObject(message);  

            System.out.println("JSON字元串："+demoJson);  

            access_token = demoJson.getString("access_token");  

            is.close();  

        } catch (Exception e) {  

                e.printStackTrace();  

        }  

        return access_token;  

    }  

    public static String getTicket(String access_token) {  

        String ticket = null;  

        String url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?access_token="+ access_token +"&type=jsapi";//這個url連結和參數不能變  

        try {  

            URL urlGet = new URL(url);  

            HttpURLConnection http = (HttpURLConnection) urlGet.openConnection();  

            http.setRequestMethod("GET"); // 必須是get方式請求  

            http.setRequestProperty("Content-Type","application/x-www-form-urlencoded");  

            http.setDoOutput(true);  

            http.setDoInput(true);  

            System.setProperty("sun.net.client.defaultConnectTimeout", "30000");// 連接配接逾時30秒  

            System.setProperty("sun.net.client.defaultReadTimeout", "30000"); // 讀取逾時30秒  

            http.connect();  

            InputStream is = http.getInputStream();  

            int size = is.available();  

            byte[] jsonBytes = new byte[size];  

            is.read(jsonBytes);  

            String message = new String(jsonBytes, "UTF-8");  

            JSONObject demoJson = JSONObject.fromObject(message);  

            System.out.println("JSON字元串："+demoJson);  

            ticket = demoJson.getString("ticket");  

            is.close();  

        } catch (Exception e) {  

                e.printStackTrace();  

        }  

        return ticket;  

    }  

    public static String SHA1(String decript) {  

        try {  

            MessageDigest digest = java.security.MessageDigest.getInstance("SHA-1");  

            digest.update(decript.getBytes());  

            byte messageDigest[] = digest.digest();  

            // Create Hex String  

            StringBuffer hexString = new StringBuffer();  

            // 位元組數組轉換為 十六進制 數  

                for (int i = 0; i < messageDigest.length; i++) {  

                    String shaHex = Integer.toHexString(messageDigest[i] & 0xFF);  

                    if (shaHex.length() < 2) {  

                        hexString.append(0);  

                    }  

                    hexString.append(shaHex);  

                }  

                return hexString.toString();  

            } catch (NoSuchAlgorithmException e) {  

                e.printStackTrace();  

            }  

            return "";  

    }