这次给的任务是看一下支付宝的app支付这块。于是通过网上进行查找相关的资料，进行相关的开发，并记录下来。通过支付宝的官网进行查看：https://docs.open.alipay.com/203
1.引入支付宝的SDK的依赖；

  <dependency>
            <groupId>com.alipay.sdk</groupId>
            <artifactId>alipay-sdk-java</artifactId>
            <version>3.7.89.ALL</version>
  </dependency>

2.H5(app)请求支付宝支付的必要参数：
1）appid:

2)支付网关
a.沙箱测试的话，支付宝网关为：

https://openapi.alipaydev.com/gateway.do

b.上线正式环境的话，支付宝的网关为：

https://openapi.alipay.com/gateway.do

3）商户私钥
3.1)windows环境下载秘钥的生成工具的地址：https://docs.open.alipay.com/291/105971/
3.2)用如下图选择方式生成秘钥：

3.3)通过工具生成密钥后，这里的秘钥即是商户私钥；

3.4)将应用私钥复制到代码中：

3.5)将里面的公钥复制到网页中，https://openhome.alipay.com/platform/appDaily.htm?tab=info
如下图所示：

3.6)接着查看支付宝公钥并复制，这里就是支付宝的公钥。

3.7)复制到代码中，如图所示：

4.代码模块，首先是配置参数的模块：

public class AliPayConfig {
    //支付宝移动端appid
    public static final String ALIPAY_APP_APPID = "";

    //支付宝商户私钥
    public static final String ALIPAY_PRIVATE_KEY = "";
    //支付宝公钥
    public static final String ALIPAY_PUBLIC_KEY = "";
    //支付宝网关
    public static final String ALIPAY_GATEWAY_URL = "https://openapi.alipay.com/gateway.do";

    // 验证方式
    public static final String SIGN_TYPE = "RSA2";

    // 返回路径
    public static final String ALIPAY_NOTIFYURL = "";

    // 传输方式
    public static final String FORMAT = "json";

    // 字符串格式
    public static final String CHARSET = "UTF-8";

    private static AlipayClient alipayClient = null;

    public static AlipayClient getAlipayClient() throws AlipayApiException {
        //实例化客户端
        if (alipayClient == null) {
            synchronized (AliPayUtil.class) {
                if (null == alipayClient) {
                    alipayClient = new DefaultAlipayClient(ALIPAY_GATEWAY_URL, ALIPAY_APP_APPID, ALIPAY_PRIVATE_KEY,
                            FORMAT, CHARSET, ALIPAY_PUBLIC_KEY, SIGN_TYPE);
                }
            }
        }
        return alipayClient;
    }
}

5.工具类，里面两个方法，一个支付，一个回掉方法。

public class H5PayUtil {

    @Value("${callback.url}")
    private String callbackUrl;

    private static ObjectMapper mapper = new ObjectMapper();

    /**
     * H5请求支付宝支付
     * @param h5PayDto
     * @return
     */
    public AlipayTradeWapPayResponse aliPayH5(H5PayDto h5PayDto) {
        try {
            AlipayClient alipayClient = AliPayConfig.getAlipayClient();
            AlipayTradeWapPayRequest request = new AlipayTradeWapPayRequest();
            request.setNotifyUrl("");
            request.setBizContent(getAliPayRequest(h5PayDto).toString());
            request.setReturnUrl(h5PayDto.getReturnUrl());
            AlipayTradeWapPayResponse responseStr = alipayClient.pageExecute(request);
            log.info(responseStr.getBody());
            return responseStr;
        } catch (Exception e) {
            e.printStackTrace();
        }
      return  null;
    }


    private  ObjectNode getAliPayRequest(H5PayDto  h5PayDto) throws UnsupportedEncodingException {
        ObjectNode obj = mapper.createObjectNode();
        //obj.put("subject", URLEncoder.encode(payRequest.getBody(), "GBK"));
        obj.put("subject", h5PayDto.getSubject());
        obj.put("out_trade_no", h5PayDto.getOutTradeNo());
        obj.put("timeout_express", 30d);
        //obj.put("time_expire", DateTimeUtils.getYmdhmFormatDate(System.currentTimeMillis() + DateUtils.DAY_IN_MILLS));
        obj.put("total_amount", h5PayDto.getTotalAmount());
        obj.put("quit_url", h5PayDto.getReturnUrl());
        obj.put("product_code", "QUICK_WAP_PAY");
        return obj;
    }


    /**
     * 功能描述 支付回调
     *
     * @param request
     * @return java.lang.String
     */
    public String aliPayNotify(HttpServletRequest request) {
        Map<String, String> params = Maps.newHashMap();
        try {
            //获取支付宝POST过来反馈信息
            Map requestParams = request.getParameterMap();
            for (Iterator iter = requestParams.keySet().iterator(); iter.hasNext(); ) {
                String name = (String) iter.next();
                String[] values = (String[]) requestParams.get(name);
                String valueStr = "";
                for (int i = 0; i < values.length; i++) {
                    valueStr = (i == values.length - 1) ? valueStr + values[i]
                            : valueStr + values[i] + ",";
                }
                //乱码解决，这段代码在出现乱码时使用。
                valueStr = new String(valueStr.getBytes("ISO-8859-1"), "utf-8");
                params.put(name, valueStr);
            }
            //调用SDK验证签名
            boolean flag = AlipaySignature.rsaCheckV1(params, AliPayConfig.ALIPAY_PUBLIC_KEY, AliPayConfig.CHARSET,
                    AliPayConfig.SIGN_TYPE);
            if (flag) { // 验证成功
                return "success";
            }

        } catch (Exception e) {
            log.info("aliPayNotify exception={}", e);
            return "fail";
        }
        return "fail";
    }



}

6.需要的参数实体

   @ApiModelProperty(value = "商品的标题", required = true)
    @NotNull(message = "缺少请求参数")
    private String subject;

    @ApiModelProperty(value = "订单号", required = true)
    @NotNull(message = "缺少请求参数")
    private String outTradeNo;

    @ApiModelProperty(value = "金额", required = true)
    @NotNull(message = "缺少请求参数")
    private String totalAmount;

    @ApiModelProperty(value = "支付成功后回跳地址")
    private String  returnUrl;

7.通过接口H5请求支付宝接口

    @PostMapping("/H5Pay")
    @ApiOperation(value = "根据订单号进行支付", notes = "H5调用支付宝支付接口")
    @SneakyThrows
    public ResponseClass<String> pay(@RequestBody H5PayDto h5PayDto) {
        String result = h5PayUtil.aliPayH5(h5PayDto).getBody();
        log.info("支付宝返回的信息是:" + result);
        return ResponseClass.ok(result);
    }

8.支付回掉的controller

   @Autowired
    private H5PayUtil h5PayUtil;

    @RequestMapping("/H5PayNotice")
    public String orderNotify(HttpServletRequest request) {
        String alipayNotice = h5PayUtil.aliPayNotify(request);
        return alipayNotice;
    }

9.进行接口的请求。如图，返回了一个from表单，即可表示H5请求支付宝已成功。接下来可以和前端进行联调

支付的代码上传至GitHub上：
https://github.com/virtuousOne/pay