WxPayUnifiedOrderRequest 增加默认构造方法

weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/request/WxPayUnifiedOrderRequest.java

@@ -4,11 +4,8 @@ import com.github.binarywang.wxpay.config.WxPayConfig;
 import com.github.binarywang.wxpay.exception.WxPayException;
 import com.thoughtworks.xstream.annotations.XStreamAlias;
 import me.chanjar.weixin.common.annotation.Required;
-import org.apache.commons.lang3.ArrayUtils;
 import org.apache.commons.lang3.StringUtils;
 
-import java.util.Arrays;
-
 /**
  * <pre>
  * 统一下单请求参数对象
@@ -274,6 +271,9 @@ public class WxPayUnifiedOrderRequest extends WxPayBaseRequest {
   @XStreamAlias("openid")
   private String openid;
 
+  public WxPayUnifiedOrderRequest() {
+  }
+
   private WxPayUnifiedOrderRequest(Builder builder) {
     setAppid(builder.appid);
     setDeviceInfo(builder.deviceInfo);