拷贝对象工具类（对象赋值）copyProperties——为null不复制

开发在中经常需要将一个对象的若干个值赋值给另外一个对象相对应的字段，且字段名是一样的，如果一个一个取一个一个赋值

太麻烦，使用​​

​org.springframework.beans.BeanUtils​

​的copyProperties方法，有个弊端就是会将null也复制过来

自己写个工具类，继承​

​org.springframework.beans.BeanUtils​

​

对该方法进行改造，如代码中注释部分

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);
        PropertyDescriptor[] var7 = targetPds;
        int var8 = targetPds.length;

        for (int var9 = 0; var9 < var8; ++var9) {
            PropertyDescriptor targetPd = var7[var9];
            Method writeMethod = targetPd.getWriteMethod();
            if (writeMethod != null) {
                PropertyDescriptor sourcePd = getPropertyDescriptor(source.getClass(), targetPd.getName());
                if (sourcePd != null) {
                    Method readMethod = sourcePd.getReadMethod();
                    if (readMethod != null && ClassUtils.isAssignable(writeMethod.getParameterTypes()[0], readMethod.getReturnType())) {
                        try {
                            if (!Modifier.isPublic(readMethod.getDeclaringClass().getModifiers())) {
                                readMethod.setAccessible(true);
                            }
                            Object value = readMethod.invoke(source);
                            if (value != null) {//这里判断以下value是否为空
                                if (!Modifier.isPublic(writeMethod.getDeclaringClass().getModifiers())) {
                                    writeMethod.setAccessible(true);
                                }
                                writeMethod.invoke(target, value);
                            }
                        } catch (Throwable var15) {
                            throw new FatalBeanException("Could not copy property '" + targetPd.getName() + "' from source to target", var15);
                        }
                    }
                }
            }
        }
    }