java实现支付宝退款功能

import org.slf4j.Logger;import org.slf4j.LoggerFactory; import com.alipay.api.AlipayClient;import com.alipay.api.DefaultAlipayClient;import com.alipay.api.domain.AlipayTradeRefundModel;import com.alipay.api.request.AlipayTradeRefundRequest;import com.alipay.api.response.AlipayTradeRefundResponse; public class AlipayUtil {  private static final Logger LOGGER = LoggerFactory.getLogger(AlipayUtil.class);  private static String APP_ID = "234789720984098";  //支付宝退款请求的网关 private static String requestUrl = "https://openapi.alipay.com/gateway.do"; //用户自己生成的私钥 private static String APP_PRIVATE_KEY = "随机字符，见文档"; //支付宝公钥 private static String ALIPAY_PUBLIC_KEY = "从支付宝中获得";  //编码级别 private static String CHARSET = "UTF-8";  public static String refundOrder(AliRefundTO aliRefundTO){ System.out.println("开始调用支付宝加密******************************************************"); //实例化客户端  AlipayClient alipayClient = new DefaultAlipayClient(requestUrl, APP_ID, APP_PRIVATE_KEY, "json", CHARSET, ALIPAY_PUBLIC_KEY, "RSA2");  //SDK已经封装掉了公共参数，这里只需要传入业务参数。以下方法为sdk的model入参方式(model和biz_content同时存在的情况下取biz_content)。  AlipayTradeRefundModel refundModel = new AlipayTradeRefundModel();  refundModel.setTradeNo(aliRefundTO.getTrade_no());  refundModel.setRefundAmount(aliRefundTO.getRefund_amount());  refundModel.setRefundReason("商品退款");  //实例化具体API对应的request类,类名称和接口名称对应,当前调用接口名称：alipay.trade.app.pay  AlipayTradeRefundRequest request = new AlipayTradeRefundRequest();  request.setBizModel(refundModel);  try{  AlipayTradeRefundResponse response = alipayClient.execute(request);  System.out.println(response.getMsg()+"/n");  System.out.println(response.getBody());  }catch(Exception e){  e.printStackTrace();  LOGGER.error("支付宝退款错误！",e.getMessage());    }   return "";   }  public static void main(String[] arg){ AliRefundTO aliRefundTO=new AliRefundTO(); aliRefundTO.setRefund_amount("0.01"); aliRefundTO.setTrade_no("2018050421001004310518105890"); String res=refundOrder(aliRefundTO); }}