//編碼
NSString *str = @"??";
NSString *uniStr = [NSString stringWithUTF8String:[str UTF8String]];
NSData *uniData = [uniStr dataUsingEncoding:NSNonLossyASCIIStringEncoding];
NSString *goodStr = [[NSString alloc] initWithData:uniData encoding:NSUTF8StringEncoding] ;
NSLog(@"---編碼--->[%@]",goodStr);

//解碼
const char *jsonString = [goodStr UTF8String];   // goodStr 服務(wù)器返回的 json
NSData *jsonData = [NSData dataWithBytes:jsonString length:strlen(jsonString)];
NSString *goodMsg1 = [[NSString alloc] initWithData:jsonData encoding:NSNonLossyASCIIStringEncoding];
NSLog(@"---解碼--->[%@]",goodMsg1);