json解析后的数组进行排序

            NSSortDescriptor *sortDescriptor;
            
            sortDescriptor = [[NSSortDescriptor alloc]initWithKey:@"dtDateReal" ascending:NO];
            
            NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
            
            NSArray *sortedArray;
            
            sortedArray = [self.courseLists sortedArrayUsingDescriptors:sortDescriptors];
            
            self.courseLists = sortedArray;

参考网址http://segmentfault.com/q/1010000000120607