爲了獲得長期有效的access_token,不能每次都從服務器生成,本文采用存儲在文件中,超過一定時間再定時刷新的方法,直接看代碼。
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import javax.net.ssl.HttpsURLConnection;
import com.google.gson.Gson;
import com.google.gson.JsonSyntaxException;
/*
* 該類測試了直接獲取Access_token和保存後判斷Access_token存活時間後再獲取兩種方式【使用時,使用該方式】。
*/
public class Access_tokenDemo {
private static final long MAX_TIME = 7200 * 1000;// 微信允許最長Access_token有效時間(ms)
private static final String TAG = "WeixinApiTest";// TAG
private static final String APPID = "your appId";// APPID
private static final String SECERT = "your appSecret";// 祕鑰
/*
* 該方法實現獲取Access_token、保存並且只保存2小時Access_token。如果超過兩個小時重新獲取;如果沒有超過兩個小時,直接獲取。該方法依賴
* :public static String getAccessToken();
*
* 思路:將獲取到的Access_token和當前時間存儲到file裏,
* 取出時判斷當前時間和存儲裏面的記錄的時間的時間差,如果大於MAX_TIME,重新獲取,並且將獲取到的存儲到file替換原來的內容
* ,如果小於MAX_TIME,直接獲取。
*/
public String getSavedAccess_token() {
Gson gson = new Gson();
String mAccess_token = null;// 需要獲取的Access_token;
File file = new File("temp_access_token.temp");// Access_token保存的位置
try {
// 如果文件不存在,創建
if (!file.exists())
file.createNewFile();
// 如果文件大小等於0,說明第一次使用,存入Access_token
if (file.length() == 0) {
mAccess_token = getAccessToken();
FileOutputStream fos = new FileOutputStream(file, false);// 不允許追加
Access_token at = new Access_token();
at.setAccess_token(mAccess_token);
at.setExpires_in(System.currentTimeMillis() + "");
String json = gson.toJson(at);
fos.write((json).getBytes());
fos.close();
} else {
// 讀取文件內容
FileInputStream fis = new FileInputStream(file);
byte[] b = new byte[2048];
int len = fis.read(b);
String mJsonAccess_token = new String(b, 0, len);// 讀取到的文件內容
Access_token access_token = gson.fromJson(mJsonAccess_token,
new Access_token().getClass());
if (access_token.getExpires_in() != null) {
long saveTime = Long.parseLong(access_token.getExpires_in());
System.out.println("saveTime:"+saveTime);
long nowTime = System.currentTimeMillis();
System.out.println("nowTime:"+nowTime);
long remianTime = nowTime - saveTime;
System.out.println("時間差:" +remianTime);
// System.out.println(TAG + "時間差:" + remianTime);
if (remianTime < MAX_TIME) {
Access_token at = gson.fromJson(mJsonAccess_token,
new Access_token().getClass());
mAccess_token = at.getAccess_token();
} else {
mAccess_token = getAccessToken();
FileOutputStream fos = new FileOutputStream(file, false);// 不允許追加
Access_token at = new Access_token();
at.setAccess_token(mAccess_token);
at.setExpires_in(System.currentTimeMillis() + "");
String json = gson.toJson(at);
fos.write((json).getBytes());
fos.close();
}
}
}
} catch (JsonSyntaxException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("獲取到的Access_token是:" + mAccess_token);
return mAccess_token;
}
/*
* 獲取微信服務器AccessToken。該部分和getAccess_token() 一致,不再加註釋
*/
public static String getAccessToken() {
String urlString = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid="
+ APPID + "&secret=" + SECERT;
String reslut = null;
try {
URL reqURL = new URL(urlString);
HttpsURLConnection httpsConn = (HttpsURLConnection) reqURL
.openConnection();
InputStreamReader isr = new InputStreamReader(
httpsConn.getInputStream());
char[] chars = new char[1024];
reslut = "";
int len;
while ((len = isr.read(chars)) != -1) {
reslut += new String(chars, 0, len);
}
isr.close();
} catch (IOException e) {
e.printStackTrace();
}
Gson gson = new Gson();
Access_token access_token = gson.fromJson(reslut,
new Access_token().getClass());
if (access_token.getAccess_token() != null) {
return access_token.getAccess_token();
} else {
return null;
}
}
}
本文參考了高遠的博客http://blog.csdn.net/wgyscsf/article/details/51078372
,並略作了修改。