## 从私钥文件中将私钥文件获取出来
```java
BufferedReader mBufferedReader = null;
try {
FileReader mFileReader = new FileReader(new File(
"rsa_private_key_pkcs82.pem"));
mBufferedReader = new BufferedReader(mFileReader);
StringBuilder sb = new StringBuilder();
String line = "";
while (null != (line = mBufferedReader.readLine())) {
if (!line.startsWith("-----")) {
sb.append(line);
}
}
privateKey = sb.toString();
} catch (FileNotFoundException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (null != mBufferedReader) {
try {
mBufferedReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
```
2、生成订单信息
```java
MaporderInfoM = new HashMap<>();
orderInfoM.put("app_id", "2016092601974191");
orderInfoM.put("charset", "utf-8");
orderInfoM.put("format", "json");
orderInfoM.put("method", "alipay.trade.app.pay");
orderInfoM.put("notify_url", "http://www.mytian.com.cn/myt_pay/payAction_alipayNotify.do");
orderInfoM.put("sign_type", "RSA");
orderInfoM.put("timestamp", "2016-10-19 10:29:10");
orderInfoM.put("version", "1.0");
MapbizContent = new LinkedHashMap<>();
bizContent.put("timeout_express", "30m");
bizContent.put("seller_id", "xiaosong.xu@mytian.com.cn");
bizContent.put("product_code", "QUICK_MSECURITY_PAY");
bizContent.put("total_amount", "0.01");
bizContent.put("subject", "进阶套餐54元");
bizContent.put("body", "原价120（4.5折）6000麦粒");
bizContent.put("out_trade_no", "2961476844150427");
orderInfoM.put("biz_content", JSONObject.toJSONString(bizContent));
```
3、将订单信息用ali SDK 拼接成待签名字符串
```java
String content = AlipaySignature.getSignContent(orderInfoM);
app_id=2016092601974191&biz_content={"timeout_express":"30m","seller_id":"xiaosong.xu@mytian.com.cn","product_code":"QUICK_MSECURITY_PAY","total_amount":"0.01","subject":"进阶套餐54元","body":"原价120（4.5折）6000麦粒","out_trade_no":"2961476844150427"}&charset=utf-8&format=json&method=alipay.trade.app.pay¬ify_url=http://www.mytian.com.cn/myt_pay/payAction_alipayNotify.do&sign_type=RSA×tamp=2016-10-19 10:29:10&version=1.0
```
进行签名
sign=Cxn8TH6OqgRruFNPzU1YUUnPcYdFn2KFsSHRDipOd2oKXVL3GS6vUD44uWCVttORA62l/YEUEeZAdavlimx6slxCgSay3x1pvKKrwTrPE1RYfFEsjETvaiaJZGz5AQRhPvP5Oqw9SBky3nV2CpKrY6JFJ2kS1w7jfJPeYDxbNXU=
将所有的values新URLEncoder转义
```java
getSignContent(orderInfoM)+"&sign="+URLEncoder.encode(sign, "UTF-8")
public static String getSignContent(MapsortedParams) { StringBuffer content = new StringBuffer(); Listkeys = new ArrayList(sortedParams.keySet());
Collections.sort(keys);
int index = 0;
for (int i = 0; i < keys.size(); ++i) {
String key = (String) keys.get(i);
String value = (String) sortedParams.get(key);
if (StringUtils.areNotEmpty(new String[] { key, value })) {
try {
content.append(((index == 0) ? "" : "&") + key + "=" + URLEncoder.encode(value, "UTF-8"));
} catch (UnsupportedEncodingException e) {
content.append(((index == 0) ? "" : "&") + key + "=" + value);
}
++index;
}
}
return content.toString();
}
```
得到最终的字符串，响应请求
app_id=2016092601974191&biz_content=%7B%22timeout_express%22%3A%2230m%22%2C%22seller_id%22%3A%22xiaosong.xu%40mytian.com.cn%22%2C%22product_code%22%3A%22QUICK_MSECURITY_PAY%22%2C%22total_amount%22%3A%220.01%22%2C%22subject%22%3A%22%E8%BF%9B%E9%98%B6%E5%A5%97%E9%A4%9054%E5%85%83%22%2C%22body%22%3A%22%E5%8E%9F%E4%BB%B7120%EF%BC%884.5%E6%8A%98%EF%BC%896000%E9%BA%A6%E7%B2%92%22%2C%22out_trade_no%22%3A%222961476844150427%22%7D&charset=utf-8&format=json&method=alipay.trade.app.pay¬ify_url=http%3A%2F%2Fwww.mytian.com.cn%2Fmyt_pay%2FpayAction_alipayNotify.do&sign_type=RSA×tamp=2016-10-19+10%3A29%3A10&version=1.0&sign=Cxn8TH6OqgRruFNPzU1YUUnPcYdFn2KFsSHRDipOd2oKXVL3GS6vUD44uWCVttORA62l%2FYEUEeZAdavlimx6slxCgSay3x1pvKKrwTrPE1RYfFEsjETvaiaJZGz5AQRhPvP5Oqw9SBky3nV2CpKrY6JFJ2kS1w7jfJPeYDxbNXU%3D
