使用NSDictionary从JSONObject检索数据

{
    "name": "John",
    "age": 30,
    "city": "New York"
}

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // JSON 字符串
        NSString *jsonString = @"{\"name\":\"John\",\"age\":30,\"city\":\"New York\"}";
        
        // 将 JSON 字符串解析成 NSData
        NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
        
        // 解析 JSON 数据为 NSDictionary
        NSError *error;
        NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error];
        
        if (error) {
            NSLog(@"Error parsing JSON: %@", error);
            return 1;
        }
        
        // 从 NSDictionary 中检索数据
        NSString *name = jsonDict[@"name"];
        NSNumber *age = jsonDict[@"age"];
        NSString *city = jsonDict[@"city"];
        
        NSLog(@"Name: %@", name);
        NSLog(@"Age: %@", age);
        NSLog(@"City: %@", city);
    }
    return 0;
}

id value = jsonDict[@"nonExistentKey"];
if (value == nil) {
    NSLog(@"Key does not exist");
}