trust-dns 不再需要，使用 trust-dns-proto 即可。

    1. use std::env;
    2. use trust_dns_proto::rr::record_type::RecordType;
    3. use trust_dns_resolver::config::*;
    4. use trust_dns_resolver::Resolver;
    6. fn main() {
    7.     let args: Vec<String> = env::args().collect();
    8.     if args.len() != 2 {
    9.         eprintln!("Please enter a name to query!");
    10.         std::process::exit(1);
    11.     }
    13.     let query = format!("{}", args[1]);
    15.     let resolver = Resolver::new(ResolverConfig::default(), Default::default()).unwrap();
    16.     let response = resolver.lookup_ip(query.as_str());
    18.     for ans in response.iter() {
    19.         println!("{:?}", ans);
    20.     }
    22.     // 从系统配置创建 /etc/resolv.conf
    23.     let resolver = Resolver::from_system_conf().unwrap();
    24.     let response = resolver.lookup_ip(query.as_str());
    25.     for ans in response.iter() {
    26.         println!("{:?}", ans);
    27.     }
    29.     let ns = resolver.lookup(query.as_str(), RecordType::NS);
    30.     for ans in ns.iter() {
    31.         println!("{:?}", ans);
    32.     }
    33. }