模拟dns优选，处理dns的响应时间

说明

主要用于选择更合适的dns解析服务器。可以自定义配置需要测试的dns地址。 如果你们的宽带是电信联通或移动可以去查询它们所在城市的dns地址也可以加入测试

配置文件 dnstest.ini

#要进行解析的域名
test www.baidu.com
test www.oschina.com
test tv.sohu.com#可用的dns。
dns 8.8.8.8
dns 8.8.4.4
dns 114.114.114.114
dns 114.114.115.115
dns 223.5.5.5
dns 223.6.6.6
dns 1.2.4.8
dns 210.2.4.8
dns 208.67.222.222
dns 208.67.220.220
dns 101.226.4.6
dns 123.125.82.6
dns 123.125.83.6

代码

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;public class DNSSpeed implements Runnable {private final InetAddress dns;private final String dd;public DNSSpeed(String dns, String dd) throws UnknownHostException {this.dns = InetAddress.getByName(dns);this.dd = dd;}public void run() {byte[] data = toDnsBytes(dd);DatagramSocket dispatcher = null;DatagramPacket pack = null;boolean isSuccess = false;long start = System.currentTimeMillis();try {pack = new DatagramPacket(data, data.length, dns, 53);dispatcher = createDatagramSocket();dispatcher.setSoTimeout(1000);dispatcher.send(pack);data = new byte[512];pack = new DatagramPacket(data, data.length);dispatcher.receive(pack);if (pack.getLength() > 12) {//简单验证返回包isSuccess = true;}} catch (Exception e) {} finally {if (null != dispatcher) {dispatcher.close();}String info = "%-15s\t%-20s\t%s\t%4d\t";info = String.format(info, dns.getHostAddress(), dd, isSuccess, (System.currentTimeMillis() - start));System.out.println(info);}}/*** 组dns查询包* 2015年7月14日* @param dd* @return*/protected static final byte[] toDnsBytes(String dd) {ByteBuffer b = ByteBuffer.allocateDirect(512);short id = (short) (3 + r.nextInt(1000));b.putShort(id);// id;b.put((byte) 0x01);b.put((byte) 0x00);b.putShort((short) (0x01 & 0xFFFF));b.putShort((short) (0x00 & 0xFFFF));b.putShort((short) (0x00 & 0xFFFF));b.putShort((short) (0x00 & 0xFFFF));String[] ss = dd.split("\\.");for (int i = 0; i < ss.length; i++) {byte[] bb = ss[i].getBytes();b.put((byte) (bb.length & 0xFF));b.put(bb);}b.put((byte) 0x00);b.putShort((short) 0x01);b.putShort((short) 0x01);b.flip();byte[] bb = new byte[b.remaining()];b.get(bb);return bb;}private static Random r = new Random();/*** 随机取一个 50000开始的端口* 2015年7月14日* @return*/private static synchronized DatagramSocket createDatagramSocket() {DatagramSocket result = null;while (null == result) {try {int port = 50000 + r.nextInt(10000);result = new DatagramSocket(port);} catch (SocketException e) {result = null;} finally {}}return result;}public static void main(String[] args) throws UnknownHostException {List<String> config = loadFile("dnstest.ini");List<String> dns = getConfig(config, "dns");List<String> test = getConfig(config, "test");for (String s : dns) {for (String t : test) {new DNSSpeed(s, t).run();}}}/*** 取key. 配置以 key  value格式* 2015年7月14日* @param config* @param key* @return*/protected static final List<String> getConfig(List<String> config, String key) {List<String> result = new ArrayList<String>();for (String ss : config) {ss = ss.trim();if (ss.startsWith(key)) {result.add(ss.substring(key.length()).trim());}}return result;}/*** 加载配置文件转list* 2015年7月14日* @param path* @return*/protected static final List<String> loadFile(String path) {List<String> result = new ArrayList<String>();BufferedReader in = null;try {in = new BufferedReader(new FileReader(path));String s = null;while (null != (s = in.readLine())) {s = s.trim();if (!s.startsWith("#") && !s.isEmpty()) {//过滤掉空行及#号开头的配置result.add(s);}}} catch (Exception e) {e.printStackTrace();} finally {if (null != in) {try {in.close();} catch (IOException e) {}}}return result;}
}

执行结果

8.8.8.8         www.baidu.com           true      12
8.8.8.8         www.oschina.com         true       4
8.8.8.8         tv.sohu.com             true       7
8.8.4.4         www.baidu.com           true       7
8.8.4.4         www.oschina.com         true       8
8.8.4.4         tv.sohu.com             true       6
114.114.114.114 www.baidu.com           true       5
114.114.114.114 www.oschina.com         true       6
114.114.114.114 tv.sohu.com             true       8
114.114.115.115 www.baidu.com           true       5
114.114.115.115 www.oschina.com         true       6
114.114.115.115 tv.sohu.com             true       5
223.5.5.5       www.baidu.com           true      41
223.5.5.5       www.oschina.com         true      44
223.5.5.5       tv.sohu.com             true      42
223.6.6.6       www.baidu.com           true      40
223.6.6.6       www.oschina.com         true      45
223.6.6.6       tv.sohu.com             true      46
1.2.4.8         www.baidu.com           true       8
1.2.4.8         www.oschina.com         true       6
1.2.4.8         tv.sohu.com             true      13
210.2.4.8       www.baidu.com           true       6
210.2.4.8       www.oschina.com         true       8
210.2.4.8       tv.sohu.com             true     187
208.67.222.222  www.baidu.com           true       5
208.67.222.222  www.oschina.com         true       6
208.67.222.222  tv.sohu.com             true       4
208.67.220.220  www.baidu.com           true       5
208.67.220.220  www.oschina.com         true       7
208.67.220.220  tv.sohu.com             true      10
101.226.4.6     www.baidu.com           true       5
101.226.4.6     www.oschina.com         true       5
101.226.4.6     tv.sohu.com             true       6
123.125.82.6    www.baidu.com           true       5
123.125.82.6    www.oschina.com         true       7
123.125.82.6    tv.sohu.com             true       5
123.125.83.6    www.baidu.com           true       5
123.125.83.6    www.oschina.com         true       5
123.125.83.6    tv.sohu.com             true       6