//    //1、json转换成对象 
 
//    NSString * path = [[NSBundle mainBundle] pathForResource:@"test.json" ofType:nil]; 
 
//    NSData * data = [NSData dataWithContentsOfFile:path]; 
 
//    NSDictionary * dic = [ NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil]; 
 
//    NSArray * array = dic[@"class1"]; 
 
//     
 
//    for (NSDictionary * dic in array) 
 
//    { 
 
//         
 
//    //2.对象转成data 
 
//        NSData * data = [NSJSONSerialization dataWithJSONObject:dic options:NSJSONWritingPrettyPrinted error:nil]; 
 
//        NSString * str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]; 
 
//        NSLog(@"%@", str); 
 
//         
 
//    }