Merge branch 'wangfei' into 'dev'

1、新增copyBean的工具类。

See merge request !145

ruoyi-common/src/main/java/com/ruoyi/common/utils/bean/BeanUtils.java

 package com.ruoyi.common.utils.bean;
 
+import java.beans.BeanInfo;
+import java.beans.Introspector;
+import java.beans.PropertyDescriptor;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.List;
@@ -107,4 +110,30 @@ public class BeanUtils extends org.springframework.beans.BeanUtils
     {
         return m1.substring(BEAN_METHOD_PROP_INDEX).equals(m2.substring(BEAN_METHOD_PROP_INDEX));
     }
+
+    public static <M> void mergeObject(M target, M source) {
+        BeanInfo beanInfo = null;
+        try {
+            beanInfo = Introspector.getBeanInfo(target.getClass());
+
+            // Iterate over all the attributes
+            for (PropertyDescriptor descriptor : beanInfo.getPropertyDescriptors()) {
+
+                // Only copy writable attributes
+                if (descriptor.getWriteMethod() != null) {
+                    Object originalValue = descriptor.getReadMethod()
+                            .invoke(target);
+
+                    // Only copy values where the destination values is null
+                    if (originalValue == null) {
+                        Object defaultValue = descriptor.getReadMethod().invoke(
+                                source);
+                        descriptor.getWriteMethod().invoke(target, defaultValue);
+                    }
+                }
+            }
+        } catch (Exception e) {
+            throw new RuntimeException("merge objects error", e);
+        }
+    }
 }