需求：應(yīng)用a（通常有多個(gè)）和應(yīng)用b（1個(gè)）進(jìn)行 socket通訊，應(yīng)用a必須知道應(yīng)用b的ip地址（在應(yīng)用a的配置文件中寫死的），這個(gè)時(shí)候就必須把應(yīng)用b的ip設(shè)成固定ip（但是某些時(shí)候如更換路由后要重新設(shè)置網(wǎng)絡(luò)，但是操作人員不知道這個(gè)規(guī)則），就有可能造成應(yīng)用a和應(yīng)用b無法進(jìn)行正常通訊，所以要改成應(yīng)用a動態(tài)獲取應(yīng)用b的ip地址。
經(jīng)過討論決定采用udp協(xié)議實(shí)現(xiàn)，upd是一種無連接的傳輸層協(xié)議。應(yīng)用a在不知道應(yīng)用b的 ip情況下 可以使用廣播地址255.255.255.255，將消息發(fā)送到在同一廣播網(wǎng)絡(luò)上的b。從而獲取b的ip。
實(shí)現(xiàn)代碼：
b應(yīng)用為服務(wù)端：將udp監(jiān)聽放到一個(gè)線程中，當(dāng)有客戶端請求時(shí)就會進(jìn)行響應(yīng)
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/** * udp連接，用于動態(tài)ip, pos向255.255.255.255：5060發(fā)送請求即可 * **/public class udpserver extends thread implements runnable { private final int max_length = 1024; private final int port = 5060; private datagramsocket datagramsocket; public void run() { try { init(); while(true){ try { byte[] buffer = new byte[max_length]; datagrampacket packet = new datagrampacket(buffer, buffer.length); receive(packet); string recestr = new string(packet.getdata(), 0 , packet.getlength()); system.out.println("接收數(shù)據(jù)包" + recestr); byte[] bt = new byte[packet.getlength()]; system.arraycopy(packet.getdata(), 0, bt, 0, packet.getlength()); system.out.println(packet.getaddress().gethostaddress() + "：" + packet.getport() + "：" + arrays.tostring(bt)); packet.setdata(bt); response(packet); } catch (exception e) { e.printstacktrace(); loggerutil.error("udp線程出現(xiàn)異常：" + e.tostring()); } } } catch (exception e) { e.printstacktrace(); } } public void receive(datagrampacket packet) throws exception { datagramsocket.receive(packet); } public void response(datagrampacket packet) throws exception { datagramsocket.send(packet); } /** * 初始化連接 */ public void init(){ try { datagramsocket = new datagramsocket(port); system.out.println("udp服務(wù)端已經(jīng)啟動！"); } catch (exception e) { datagramsocket = null; system.out.println("udp服務(wù)端啟動失敗！"); e.printstacktrace(); } }} |
客戶端：本來客戶端是使用pb來實(shí)現(xiàn)的，但是這里使用java來模擬
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/*** * udp client端 ***/public class udpclient { private string sendstr = "hello"; private string netaddress = "255.255.255.255"; private final int port = 5060; private datagramsocket datagramsocket; private datagrampacket datagrampacket; public udpclient(){ try { datagramsocket = new datagramsocket(); byte[] buf = sendstr.getbytes(); inetaddress address = inetaddress.getbyname(netaddress); datagrampacket = new datagrampacket(buf, buf.length, address, port); datagramsocket.send(datagrampacket); byte[] recebuf = new byte[1024]; datagrampacket recepacket = new datagrampacket(recebuf, recebuf.length); datagramsocket.receive(recepacket); string recestr = new string(recepacket.getdata(), 0 , recepacket.getlength()); //獲取服務(wù)端ip string serverip = recepacket.getadress(); } catch (socketexception e) { e.printstacktrace(); } catch (unknownhostexception e) { e.printstacktrace(); } catch (ioexception e) { e.printstacktrace(); } finally { // 關(guān)閉socket if(datagramsocket != null){ datagramsocket.close(); } } } public static void main(string[] args) { for (int i = 0; i < 100; i++) { new thread(new runnable() { @override public void run() { udpclient udpclient = new udpclient(); } }).start(); } }} |
以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持服務(wù)器之家。
原文鏈接：https://www.cnblogs.com/coderising/p/9689619.html
