BeanUtils(空值空集合空List不再复制)

BeanUtils.copyProperties使用的时候，空值也被拷贝使它边的很鸡肋。

下面对他进行扩展，支持多种空值不再拷贝

public abstract class BeanUtils extends org.springframework.beans.BeanUtils {  

    

    public static void copyProperties(Object source, Object target) throws BeansException {  

      Assert.notNull(source, "Source must not be null");  

      Assert.notNull(target, "Target must not be null");  

      Class<?> actualEditable = target.getClass();  

      PropertyDescriptor[] targetPds = getPropertyDescriptors(actualEditable);  

      for (PropertyDescriptor targetPd : targetPds) {  

        if (targetPd.getWriteMethod() != null) {  

          PropertyDescriptor sourcePd = getPropertyDescriptor(source.getClass(), targetPd.getName());  

          if (sourcePd != null && sourcePd.getReadMethod() != null) {  

            try {  

              Method readMethod = sourcePd.getReadMethod();  

              if (!Modifier.isPublic(readMethod.getDeclaringClass().getModifiers())) {  

                readMethod.setAccessible(true);  

              }  

              Object value = readMethod.invoke(source); 

             

              

              // 这里判断以下value是否为空 当然这里也能进行一些特殊要求的处理 例如绑定时格式转换等等  

              if (value != null) {  

                  boolean isEmpty = false;

                    if (value instanceof Set) {

                        Set s = (Set) value;

                        if (s == null || s.isEmpty()) {

                            isEmpty = true;

                        }

                    } else if (value instanceof Map) {

                        Map m = (Map) value;

                        if (m == null || m.isEmpty()) {

                            isEmpty = true;

                        }

                    } else if (value instanceof List) {

                        List l = (List) value;

                        if (l == null || l.size() < 1) {

                            isEmpty = true;

                        }

                    } else if (value instanceof Collection) {

                        Collection c = (Collection) value;

                        if (c == null || c.size() < 1) {

                            isEmpty = true;

                        }

                    }

                  

                if (!isEmpty) { 

                Method writeMethod = targetPd.getWriteMethod();  

                if (!Modifier.isPublic(writeMethod.getDeclaringClass().getModifiers())) {  

                  writeMethod.setAccessible(true);  

                }  

                writeMethod.invoke(target, value);  

              }  

              }

            } catch (Throwable ex) {  

              throw new FatalBeanException("Could not copy properties from source to target", ex);  

            }  

          }  

        }  

      }  

    }  

  }