支付宝APP支付（Java后台生成签名具体步骤）

 /**    *支付宝支付    * @param orderId 订单编号    * @param actualPay 实际支付金额    * @return    */ PRivate String getOrderInfoByAlipay(String orderId,float actualPay) {
      //回调页面      String ali_call_back_url = propertiesService.ALI_CALL_BACK_URL;      String seller_id = propertiesService.SELLER_ID;//商户编号      String[] parameters={            "service=/"mobile.securitypay.pay/"",//固定值（手机快捷支付）            "partner=/"2088421544444/"",//合作身份者ID（16位）
            "_input_charset=/"utf-8/"",            "notify_url=/""+ali_call_back_url+"/"",//通知地址            "out_trade_no=/""+orderId+"/"",//商户内部订单号            "subject=/"测试/"",//测试            "payment_type=/"1/"",//固定值            "seller_id=/""+seller_id+"/"",//账户邮箱           "total_fee=/""+"0.01"+"/"",//支付金额（元）            "body=/"订单说明/"",//订单说明            
            "it_b_pay=/"30m/""（订单过期时间 30分钟过期无效）      };      String signOrderUrl = signAllString(parameters);      return signOrderUrl;   }
 
/** * 支付宝签名 * @param array * @return */private String signAllString(String [] array){   StringBuffer sb = new StringBuffer("");   for (int i = 0; i < array.length; i++) {      if(i==(array.length-1)){         sb.append(array[i]);      }else{         sb.append(array[i]+"&");      }   }   System.out.println(sb.toString());   String sign = "";   try {      sign = URLEncoder.encode(RSA.sign(sb.toString(), AlipayConfig.private_key, "utf-8"), "utf-8");//private_key私钥   } catch (UnsupportedEncodingException e) {      e.printStackTrace();   }   sb.append("&sign=/""+sign+"/"&");   sb.append("sign_type=/"RSA/"");   return sb.toString();}
 
package com.alipay.sign;import javax.crypto.Cipher;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.InputStream;import java.security.KeyFactory;import java.security.PrivateKey;import java.security.PublicKey;import java.security.spec.PKCS8EncodedKeySpec;import java.security.spec.X509EncodedKeySpec;
 
public class RSA{      public static final String  SIGN_ALGORITHMS = "SHA1WithRSA";      /**   * RSA签名   * @param content 待签名数据   * @param privateKey 商户私钥   * @param input_charset 编码格式   * @return 签名值   */   public static String sign(String content, String privateKey, String input_charset)   {        try         {         byte[] decode = Base64.decode(privateKey);         PKCS8EncodedKeySpec priPKCS8   = new PKCS8EncodedKeySpec(decode );           KeyFactory keyf= KeyFactory.getInstance("RSA");           PrivateKey priKey= keyf.generatePrivate(priPKCS8);            java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);            signature.initSign(priKey);            signature.update( content.getBytes(input_charset) );            byte[] signed = signature.sign();                        return Base64.encode(signed);        }        catch (Exception e)         {           e.printStackTrace();        }                return null;    }      /**   * RSA验签名检查   * @param content 待签名数据   * @param sign 签名值   * @param ali_public_key 支付宝公钥   * @param input_charset 编码格式   * @return 布尔值   */   public static boolean verify(String content, String sign, String ali_public_key, String input_charset)   {      try       {         KeyFactory keyFactory = KeyFactory.getInstance("RSA");           byte[] encodedKey = Base64.decode(ali_public_key);           PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));         java.security.Signature signature = java.security.Signature         .getInstance(SIGN_ALGORITHMS);               signature.initVerify(pubKey);         signature.update( content.getBytes(input_charset) );               boolean bverify = signature.verify( Base64.decode(sign) );         return bverify;               }       catch (Exception e)       {         e.printStackTrace();      }            return false;   }      /**   * 解密   * @param content 密文   * @param private_key 商户私钥   * @param input_charset 编码格式   * @return 解密后的字符串   */   public static String decrypt(String content, String private_key, String input_charset) throws Exception {        PrivateKey prikey = getPrivateKey(private_key);        Cipher cipher = Cipher.getInstance("RSA");        cipher.init(Cipher.DECRYPT_MODE, prikey);        InputStream ins = new ByteArrayInputStream(Base64.decode(content));        ByteArrayOutputStream writer = new ByteArrayOutputStream();        //rsa解密的字节大小最多是128，将需要解密的内容，按128位拆开解密        byte[] buf = new byte[128];        int bufl;        while ((bufl = ins.read(buf)) != -1) {            byte[] block = null;            if (buf.length == bufl) {                block = buf;            } else {                block = new byte[bufl];                for (int i = 0; i < bufl; i++) {                    block[i] = buf[i];                }            }            writer.write(cipher.doFinal(block));        }        return new String(writer.toByteArray(), input_charset);    }      /**   * 得到私钥   * @param key 密钥字符串（经过base64编码）   * @throws Exception   */   public static PrivateKey getPrivateKey(String key) throws Exception {      byte[] keyBytes;            keyBytes = Base64.decode(key);            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);            KeyFactory keyFactory = KeyFactory.getInstance("RSA");            PrivateKey privateKey = keyFactory.generatePrivate(keySpec);            return privateKey;   }}
 
 
支付宝参数里面为什么要进行转义？主要是因为返回给移动的参数结果是springmvc进行返回的给移动端时，会认为"为结束，所以需要/"进行转义！