diff --git a/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/entpay/EntPayRequest.java b/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/entpay/EntPayRequest.java
index fd04fb83c..24c1c185a 100644
--- a/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/entpay/EntPayRequest.java
+++ b/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/entpay/EntPayRequest.java
@@ -25,6 +25,8 @@ import me.chanjar.weixin.common.util.json.WxGsonBuilder;
 @AllArgsConstructor
 @XStreamAlias("xml")
 public class EntPayRequest extends BaseWxPayRequest {
+  private static final long serialVersionUID = 8647710192770447579L;
+
   /**
    * <pre>
    * 字段名：公众账号appid.
@@ -189,11 +191,6 @@ public class EntPayRequest extends BaseWxPayRequest {
     this.mchId = mchId;
   }
 
-  @Override
-  public String toString() {
-    return WxGsonBuilder.create().toJson(this);
-  }
-
   @Override
   protected String[] getIgnoredParamsForSign() {
     return new String[]{"sign_type"};
diff --git a/weixin-java-pay/src/test/java/com/github/binarywang/wxpay/bean/entpay/EntPayRequestTest.java b/weixin-java-pay/src/test/java/com/github/binarywang/wxpay/bean/entpay/EntPayRequestTest.java
new file mode 100644
index 000000000..2a2f030fc
--- /dev/null
+++ b/weixin-java-pay/src/test/java/com/github/binarywang/wxpay/bean/entpay/EntPayRequestTest.java
@@ -0,0 +1,19 @@
+package com.github.binarywang.wxpay.bean.entpay;
+
+import org.testng.annotations.Test;
+
+import static org.testng.Assert.*;
+
+/**
+ * .
+ *
+ * @author <a href="https://github.com/binarywang">Binary Wang</a>
+ * @date 2019-08-18
+ */
+public class EntPayRequestTest {
+
+  @Test
+  public void testToString() {
+    System.out.println(EntPayRequest.newBuilder().mchId("123").build().toString());
+  }
+}