feat(pay): 补齐商家转账收款样式参数

为 TransferBillsRequest 增加 user_recv_style.type 字段，支持设置收款确认页或红包样式。补充请求体序列化回归测试，验证显式设置和省略参数的行为。

Author: lizhiyuan

weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/transfer/TransferBillsRequest.java

@@ -87,6 +87,12 @@ public class TransferBillsRequest implements Serializable {
   @SerializedName("transfer_scene_report_infos")
   private List<TransferSceneReportInfo> transferSceneReportInfos;
 
+  /**
+   * 用户收款样式；不传时默认展示收款确认页。
+   */
+  @SerializedName("user_recv_style")
+  private UserRecvStyle userRecvStyle;
+
   /**
    * 自动收款授权信息
    */
@@ -144,6 +150,21 @@ public static class TransferSceneReportInfo {
     private String infoContent;
   }
 
+  /**
+   * 用户收款样式。
+   */
+  @Data
+  @Builder(builderMethodName = "newBuilder")
+  @AllArgsConstructor
+  @NoArgsConstructor
+  public static class UserRecvStyle {
+    /**
+     * 样式类型：CONFIRM_PAGE 为收款确认页，RED_PACKET 为红包；红包仅支持部分转账场景且单笔金额不超过 200 元。
+     */
+    @SerializedName("type")
+    private String type;
+  }
+
   @Data
   @Builder(builderMethodName = "newBuilder")
   @AllArgsConstructor

weixin-java-pay/src/test/java/com/github/binarywang/wxpay/service/impl/TransferUserAuthorizationApiCompatibilityTest.java

@@ -11,6 +11,8 @@
 import com.github.binarywang.wxpay.bean.transfer.UserConfirmAuthorizationResult;
 import com.github.binarywang.wxpay.exception.WxPayException;
 import com.github.binarywang.wxpay.service.WxPayService;
+import com.google.gson.Gson;
+import com.google.gson.JsonObject;
 import org.testng.Assert;
 import org.testng.annotations.Test;
 
@@ -41,9 +43,34 @@ public void shouldKeepTransferBillsApiPathUnchanged() throws Exception {
 
     Assert.assertEquals(handler.lastPostWithSerialUrl, BASE_URL + "/v3/fund-app/mch-transfer/transfer-bills");
     Assert.assertFalse(handler.lastPostWithSerialBody.contains("authorization_info"));
+    Assert.assertFalse(handler.lastPostWithSerialBody.contains("user_recv_style"));
     Assert.assertEquals(result.getPackageInfo(), "transfer-package");
   }
 
+  /**
+   * 验证发起转账时用户收款样式及类型按微信接口字段名发送。
+   */
+  public void shouldSendUserRecvStyleInTransferBillsRequest() throws Exception {
+    RequestCaptureHandler handler = new RequestCaptureHandler();
+    TransferServiceImpl transferService = new TransferServiceImpl(handler.createWxPayService());
+
+    transferService.transferBills(TransferBillsRequest.newBuilder()
+      .appid("wxf636efh567hg4356")
+      .outBillNo("plfk2020042014")
+      .transferSceneId("1000")
+      .openid("o-MYE42l80oelYMDE34nYD456Xoy")
+      .transferAmount(100)
+      .transferRemark("活动奖励")
+      .userRecvStyle(TransferBillsRequest.UserRecvStyle.newBuilder()
+        .type("RED_PACKET")
+        .build())
+      .build());
+
+    JsonObject body = new Gson().fromJson(handler.lastPostWithSerialBody, JsonObject.class);
+    Assert.assertEquals(handler.lastPostWithSerialUrl, BASE_URL + "/v3/fund-app/mch-transfer/transfer-bills");
+    Assert.assertEquals(body.getAsJsonObject("user_recv_style").get("type").getAsString(), "RED_PACKET");
+  }
+
   /**
    * 验证“发起转账并完成免确认收款授权”使用独立接口路径和授权参数.
    */