增加annotation用于标识字段是否必填

weixin-java-common/src/main/java/me/chanjar/weixin/common/annotation/Required.java

@@ -0,0 +1,19 @@
+package me.chanjar.weixin.common.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * 标识某个字段是否是必填的
+ * 
+ * Created by Binary Wang on 2016/9/25.
+ * @author binarywang (https://github.com/binarywang)
+ *
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.FIELD)
+public @interface Required {
+
+}