GB2312轉換為UTF-8的方法

+ (NSData *)UTF8WithGB2312Data:(NSData *)gb2312Data  
{  
    NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);  
    NSString *str = [[NSString alloc] initWithData:gb2312Data encoding:enc];  
    NSData *utf8Data = [str dataUsingEncoding:NSUTF8StringEncoding];  
    return
 
 utf8Data;  
}  

UTF-8轉換為GB2312的方法：

+ (NSData *)GB2312WithUTF8Data:(NSData *)UTF8Data  
{  
    NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);  
    NSString *str = [[NSString alloc] initWithData:UTF8Data  encoding:NSUTF8StringEncoding];  
    NSData *gb2312Data = [str
 
 dataUsingEncoding:enc ];  
    return gb2312Data;  
}