1、json -> OC
情景：服务器返回带斜杠数据，自己解析。
eg:
result = "{\"account\":\"13656685594\",\"count\":0,\"gmtCreate\":null,\"gmtModify\":null,\"id\":0,\"staticToken\":\"5f3498854f4ecd284d772d71b0c74a33\",\"token\":\"03ff8978f6eb98150c5adf4e5fd2fc49\"}";
解析步骤：
NSData * data = [dic[@"result"] dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary * resultDic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
[[NSUserDefaults standardUserDefaults] setObject:resultDic[@"token"] forKey:@"token"];
[[NSUserDefaults standardUserDefaults] setObject:resultDic[@"staticToken"] forKey:@"staticToken"];
2、OC -> json
NSDictionary * dict = @{@"name":@"xiaoMing", @"age":@20, @"sex":@YES};
NSData * jsonData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:nil];
NSString * json = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
NSLog(@"json = %@", json);
