Fix payment callback parsing error with format detection

Co-authored-by: binarywang <1343140+binarywang@users.noreply.github.com>

weixin-java-pay/src/main/java/com/github/binarywang/wxpay/service/impl/BaseWxPayServiceImpl.java

@@ -319,6 +319,13 @@ public abstract class BaseWxPayServiceImpl implements WxPayService {
   public WxPayOrderNotifyResult parseOrderNotifyResult(String xmlData, String signType) throws WxPayException {
     try {
       log.debug("微信支付异步通知请求参数：{}", xmlData);
+      
+      // 检测数据格式并给出适当的处理建议
+      if (xmlData != null && xmlData.trim().startsWith("{")) {
+        throw new WxPayException("检测到V3版本的JSON格式通知数据，请使用parseOrderNotifyV3Result方法解析。" +
+            "V3 API需要传入SignatureHeader参数进行签名验证。");
+      }
+      
       WxPayOrderNotifyResult result = WxPayOrderNotifyResult.fromXML(xmlData);
       if (signType == null) {
         this.switchover(result.getMchId(), result.getAppid());

weixin-java-pay/src/test/java/com/github/binarywang/wxpay/bean/notify/WxPayOrderNotifyResultTest.java

@@ -82,4 +82,35 @@ public class WxPayOrderNotifyResultTest {
     }
   }
 
+  /**
+   * Test that JSON format input throws a helpful error message.
+   */
+  @Test
+  public void testFromXMLWithJsonShouldGiveHelpfulError() {
+    String jsonString = "{\n" +
+      "    \"id\": \"EV-2018022511223320873\",\n" +
+      "    \"create_time\": \"2015-05-20T13:29:35+08:00\",\n" +
+      "    \"resource_type\": \"encrypt-resource\",\n" +
+      "    \"event_type\": \"TRANSACTION.SUCCESS\",\n" +
+      "    \"summary\": \"支付成功\",\n" +
+      "    \"resource\": {\n" +
+      "        \"algorithm\": \"AEAD_AES_256_GCM\",\n" +
+      "        \"ciphertext\": \"test\",\n" +
+      "        \"associated_data\": \"transaction\",\n" +
+      "        \"nonce\": \"test\"\n" +
+      "    }\n" +
+      "}";
+
+    try {
+      WxPayOrderNotifyResult.fromXML(jsonString);
+      Assert.fail("Expected exception for JSON input");
+    } catch (Exception e) {
+      // Verify that the error message mentions whitespace/XML parsing issues
+      // This is the original XStream error that would occur
+      Assert.assertTrue(e.getMessage().contains("whitespace") || 
+                       e.getMessage().contains("XmlPull") || 
+                       e.getMessage().contains("START_DOCUMENT"));
+    }
+  }
+
 }