HttpDnsOkHttp怎么用代码实现IP直连

HTTPS（含SNI）业务场景“IP直连”方案说明一文介绍了利用HttpDns解析获得ip后进行ip直连的通用方法。但是如果您在Android端使用的网络框架是OkHttp,通过调用OkHttp提供的自定义Dns服务接口，可以更为优雅地使用HttpDns的服务。
OkHttp是一个处理网络请求的开源项目,是Android端最火热的轻量级框架,由移动支付Square公司贡献用于替代HttpUrlConnection和Apache HttpClient。随着OkHttp的不断成熟，越来越多的Android开发者使用OkHttp作为网络框架。
OkHttp默认使用系统DNS服务InetAddress进行域名解析，但同时也暴露了自定义DNS服务的接口，通过该接口我们可以优雅地使用HttpDns。

1. 自定义DNS接口


OkHttp暴露了一个Dns接口，通过实现该接口，我们可以自定义Dns服务：

1. [backcolor=transparent]public[backcolor=transparent] [backcolor=transparent]class[backcolor=transparent] [backcolor=transparent]OkHttpDns[backcolor=transparent] [backcolor=transparent]implements[backcolor=transparent] [backcolor=transparent]Dns[backcolor=transparent] [backcolor=transparent]{
2. [backcolor=transparent]    [backcolor=transparent]private[backcolor=transparent] [backcolor=transparent]static[backcolor=transparent] [backcolor=transparent]final[backcolor=transparent] [backcolor=transparent]Dns[backcolor=transparent] SYSTEM [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]Dns[backcolor=transparent].[backcolor=transparent]SYSTEM[backcolor=transparent];
3. [backcolor=transparent]    [backcolor=transparent]HttpDnsService[backcolor=transparent] httpdns[backcolor=transparent];[backcolor=transparent]//httpdns 解析服务
4. [backcolor=transparent]    [backcolor=transparent]private[backcolor=transparent] [backcolor=transparent]static[backcolor=transparent] [backcolor=transparent]OkHttpDns[backcolor=transparent] instance [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]null[backcolor=transparent];
5. [backcolor=transparent]    [backcolor=transparent]private[backcolor=transparent] [backcolor=transparent]OkHttpDns[backcolor=transparent]([backcolor=transparent]Context[backcolor=transparent] context[backcolor=transparent])[backcolor=transparent] [backcolor=transparent]{
6. [backcolor=transparent]        [backcolor=transparent]this[backcolor=transparent].[backcolor=transparent]httpdns [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]HttpDns[backcolor=transparent].[backcolor=transparent]getService[backcolor=transparent]([backcolor=transparent]context[backcolor=transparent],[backcolor=transparent] [backcolor=transparent]"account id"[backcolor=transparent]);
7. [backcolor=transparent]    [backcolor=transparent]}
8. [backcolor=transparent]    [backcolor=transparent]public[backcolor=transparent] [backcolor=transparent]static[backcolor=transparent] [backcolor=transparent]OkHttpDns[backcolor=transparent] getInstance[backcolor=transparent]([backcolor=transparent]Context[backcolor=transparent] context[backcolor=transparent])[backcolor=transparent] [backcolor=transparent]{
9. [backcolor=transparent]        [backcolor=transparent]if[backcolor=transparent]([backcolor=transparent]instance [backcolor=transparent]==[backcolor=transparent] [backcolor=transparent]null[backcolor=transparent])[backcolor=transparent] [backcolor=transparent]{
10. [backcolor=transparent]            instance [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]new[backcolor=transparent] [backcolor=transparent]OkHttpDns[backcolor=transparent]([backcolor=transparent]context[backcolor=transparent]);
11. [backcolor=transparent]        [backcolor=transparent]}
12. [backcolor=transparent]        [backcolor=transparent]return[backcolor=transparent] instance[backcolor=transparent];
13. [backcolor=transparent]    [backcolor=transparent]}
14. [backcolor=transparent]    [backcolor=transparent]@Override
15. [backcolor=transparent]    [backcolor=transparent]public[backcolor=transparent] [backcolor=transparent]List[backcolor=transparent]<[backcolor=transparent]InetAddress[backcolor=transparent]>[backcolor=transparent] lookup[backcolor=transparent]([backcolor=transparent]String[backcolor=transparent] hostname[backcolor=transparent])[backcolor=transparent] [backcolor=transparent]throws[backcolor=transparent] [backcolor=transparent]UnknownHostException[backcolor=transparent] [backcolor=transparent]{
16. [backcolor=transparent]        [backcolor=transparent]//通过异步解析接口获取ip
17. [backcolor=transparent]        [backcolor=transparent]String[backcolor=transparent] ip [backcolor=transparent]=[backcolor=transparent] httpdns[backcolor=transparent].[backcolor=transparent]getIpByHostAsync[backcolor=transparent]([backcolor=transparent]hostname[backcolor=transparent]);
18. [backcolor=transparent]        [backcolor=transparent]if[backcolor=transparent]([backcolor=transparent]ip [backcolor=transparent]!=[backcolor=transparent] [backcolor=transparent]null[backcolor=transparent])[backcolor=transparent] [backcolor=transparent]{
19. [backcolor=transparent]            [backcolor=transparent]//如果ip不为null，直接使用该ip进行网络请求
20. [backcolor=transparent]            [backcolor=transparent]List[backcolor=transparent]<[backcolor=transparent]InetAddress[backcolor=transparent]>[backcolor=transparent] inetAddresses [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]Arrays[backcolor=transparent].[backcolor=transparent]asList[backcolor=transparent]([backcolor=transparent]InetAddress[backcolor=transparent].[backcolor=transparent]getAllByName[backcolor=transparent]([backcolor=transparent]ip[backcolor=transparent]));
21. [backcolor=transparent]            [backcolor=transparent]Log[backcolor=transparent].[backcolor=transparent]e[backcolor=transparent]([backcolor=transparent]"OkHttpDns"[backcolor=transparent],[backcolor=transparent] [backcolor=transparent]"inetAddresses:"[backcolor=transparent] [backcolor=transparent]+[backcolor=transparent] inetAddresses[backcolor=transparent]);
22. [backcolor=transparent]            [backcolor=transparent]return[backcolor=transparent] inetAddresses[backcolor=transparent];
23. [backcolor=transparent]        [backcolor=transparent]}
24. [backcolor=transparent]        [backcolor=transparent]//如果返回null，走系统DNS服务解析域名
25. [backcolor=transparent]        [backcolor=transparent]return[backcolor=transparent] [backcolor=transparent]Dns[backcolor=transparent].[backcolor=transparent]SYSTEM[backcolor=transparent].[backcolor=transparent]lookup[backcolor=transparent]([backcolor=transparent]hostname[backcolor=transparent]);
26. [backcolor=transparent]    [backcolor=transparent]}
27. [backcolor=transparent]}

1. [backcolor=transparent]private[backcolor=transparent] [backcolor=transparent]void[backcolor=transparent] okhttpDnsRequest[backcolor=transparent]()[backcolor=transparent] [backcolor=transparent]{
2. [backcolor=transparent]    [backcolor=transparent]OkHttpClient[backcolor=transparent] client [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]new[backcolor=transparent] [backcolor=transparent]OkHttpClient[backcolor=transparent].[backcolor=transparent]Builder[backcolor=transparent]()
3. [backcolor=transparent]    [backcolor=transparent].[backcolor=transparent]dns[backcolor=transparent]([backcolor=transparent]OkHttpDns[backcolor=transparent].[backcolor=transparent]getInstance[backcolor=transparent]([backcolor=transparent]getApplicationContext[backcolor=transparent]()))
4. [backcolor=transparent]    [backcolor=transparent].[backcolor=transparent]build[backcolor=transparent]();
6. [backcolor=transparent]    [backcolor=transparent]Request[backcolor=transparent] request [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]new[backcolor=transparent] [backcolor=transparent]Request[backcolor=transparent].[backcolor=transparent]Builder[backcolor=transparent]()
7. [backcolor=transparent]    [backcolor=transparent].[backcolor=transparent]url[backcolor=transparent]([backcolor=transparent]"http://www.aliyun.com"[backcolor=transparent])
8. [backcolor=transparent]    [backcolor=transparent].[backcolor=transparent]build[backcolor=transparent]();
10. [backcolor=transparent]    [backcolor=transparent]Response[backcolor=transparent] response [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]null[backcolor=transparent];
11. [backcolor=transparent]    client[backcolor=transparent].[backcolor=transparent]newCall[backcolor=transparent]([backcolor=transparent]request[backcolor=transparent]).[backcolor=transparent]enqueue[backcolor=transparent]([backcolor=transparent]new[backcolor=transparent] [backcolor=transparent]Callback[backcolor=transparent]()[backcolor=transparent] [backcolor=transparent]{
12. [backcolor=transparent]        [backcolor=transparent]@Override
13. [backcolor=transparent]        [backcolor=transparent]public[backcolor=transparent] [backcolor=transparent]void[backcolor=transparent] onFailure[backcolor=transparent]([backcolor=transparent]Call[backcolor=transparent] call[backcolor=transparent],[backcolor=transparent] [backcolor=transparent]IOException[backcolor=transparent] e[backcolor=transparent])[backcolor=transparent] [backcolor=transparent]{
14. [backcolor=transparent]            e[backcolor=transparent].[backcolor=transparent]printStackTrace[backcolor=transparent]();
15. [backcolor=transparent]        [backcolor=transparent]}
17. [backcolor=transparent]        [backcolor=transparent]@Override
18. [backcolor=transparent]        [backcolor=transparent]public[backcolor=transparent] [backcolor=transparent]void[backcolor=transparent] onResponse[backcolor=transparent]([backcolor=transparent]Call[backcolor=transparent] call[backcolor=transparent],[backcolor=transparent] [backcolor=transparent]Response[backcolor=transparent] response[backcolor=transparent])[backcolor=transparent] [backcolor=transparent]throws[backcolor=transparent] [backcolor=transparent]IOException[backcolor=transparent] [backcolor=transparent]{
19. [backcolor=transparent]            [backcolor=transparent]if[backcolor=transparent] [backcolor=transparent](![backcolor=transparent]response[backcolor=transparent].[backcolor=transparent]isSuccessful[backcolor=transparent]())[backcolor=transparent] [backcolor=transparent]throw[backcolor=transparent] [backcolor=transparent]new[backcolor=transparent] [backcolor=transparent]IOException[backcolor=transparent]([backcolor=transparent]"Unexpected code "[backcolor=transparent] [backcolor=transparent]+[backcolor=transparent] response[backcolor=transparent]);
20. [backcolor=transparent]                [backcolor=transparent]DataInputStream[backcolor=transparent] dis [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]new[backcolor=transparent] [backcolor=transparent]DataInputStream[backcolor=transparent]([backcolor=transparent]response[backcolor=transparent].[backcolor=transparent]body[backcolor=transparent]().[backcolor=transparent]byteStream[backcolor=transparent]());
21. [backcolor=transparent]                [backcolor=transparent]int[backcolor=transparent] len[backcolor=transparent];
22. [backcolor=transparent]                [backcolor=transparent]byte[backcolor=transparent][][backcolor=transparent] buff [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]new[backcolor=transparent] [backcolor=transparent]byte[backcolor=transparent][[backcolor=transparent]4096[backcolor=transparent]];
23. [backcolor=transparent]                [backcolor=transparent]StringBuilder[backcolor=transparent] result [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]new[backcolor=transparent] [backcolor=transparent]StringBuilder[backcolor=transparent]();
24. [backcolor=transparent]                [backcolor=transparent]while[backcolor=transparent] [backcolor=transparent](([backcolor=transparent]len [backcolor=transparent]=[backcolor=transparent] dis[backcolor=transparent].[backcolor=transparent]read[backcolor=transparent]([backcolor=transparent]buff[backcolor=transparent]))[backcolor=transparent] [backcolor=transparent]!=[backcolor=transparent] [backcolor=transparent]-[backcolor=transparent]1[backcolor=transparent])[backcolor=transparent] [backcolor=transparent]{
25. [backcolor=transparent]                    result[backcolor=transparent].[backcolor=transparent]append[backcolor=transparent]([backcolor=transparent]new[backcolor=transparent] [backcolor=transparent]String[backcolor=transparent]([backcolor=transparent]buff[backcolor=transparent],[backcolor=transparent] [backcolor=transparent]0[backcolor=transparent],[backcolor=transparent] len[backcolor=transparent]));
26. [backcolor=transparent]                [backcolor=transparent]}
27. [backcolor=transparent]                [backcolor=transparent]Log[backcolor=transparent].[backcolor=transparent]d[backcolor=transparent]([backcolor=transparent]"OkHttpDns"[backcolor=transparent],[backcolor=transparent] [backcolor=transparent]"Response: "[backcolor=transparent] [backcolor=transparent]+[backcolor=transparent] result[backcolor=transparent].[backcolor=transparent]toString[backcolor=transparent]());
28. [backcolor=transparent]            [backcolor=transparent]}
29. [backcolor=transparent]        [backcolor=transparent]});
30. [backcolor=transparent]}

• 实现简单，只需通过实现Dns接口即可接入HttpDns服务
• 通用性强，该方案在HTTPS,SNI以及设置Cookie等场景均适用。规避了证书校验，域名检查等环节