public static final Class[] NO_PARAMS = new Class[0]; 定义了一个空的参数数组，跟null的效果一样，表示这个方法没有参数。 obClass.getMethod(columns[i],NO_PARAMS)表示从objClass类中查找名字为 columns[i]的没有参数的方法The parameterTypes parameter is an array of Class objects that identify the method's formal parameter types, in declared order. If parameterTypes is null, it is treated as if it were an empty array.
定义了一个空的参数数组，跟null的效果一样，表示这个方法没有参数。
obClass.getMethod(columns[i],NO_PARAMS)表示从objClass类中查找名字为
columns[i]的没有参数的方法The parameterTypes parameter is an array of Class objects that identify the method's formal parameter types, in declared order. If parameterTypes is null, it is treated as if it were an empty array.