Java C/S server

 /** <Br/> */</P> <p> Import Java. io. *; <br/> Import java.net. *; <br/>/** <br/> * @ author xinyu126 <br/> */<br/> class node {<br/> string username; <br/> Socket socket; <br/> objectoutputstream out; <br/> objectinputstream in; <br/> node next; <br/> Public node () {<br/> username = NULL; <br/> socket = NULL; <br/> out = NULL; <br/> In = NULL; <br/> next = NULL; <br/>}< br/> class onlinelist {<br/> node R OOT; <br/> node point; <br/> int count; <br/> Public onlinelist () {<br/> root = new node (); <br/> root. next = NULL; <br/> point = root; <br/> COUNT = 0; <br/>}< br/> Public void add (node) {<br/> point = root; <br/> while (point. next! = NULL) <br/> point = point. next; <br/> point. next = node; <br/> count ++; <br/> system. out. println ("online" + count); <br/>}< br/> Public void del (node) {<br/> point = root; <br/> while (point. next! = NULL) {<br/> If (point. next = node) {<br/> point. next = node. next; <br/> count --; <br/> break; <br/>}< br/> point = point. next; <br/>}< br/> system. out. println ("online" + count); <br/>}< br/> Public node find (string username) {<br/> point = root. next; <br/> while (point! = NULL) {<br/> If (point. username. equals (username) <br/> return point; <br/> point = point. next; <br/>}< br/> return NULL; <br/>}< br/> Public String showall () {<br/> string STR = ""; <br/> point = root. next; <br/> while (point! = NULL) {<br/> STR = STR + "|" + point. username; <br/> point = point. next; <br/>}< br/> return STR; <br/>}</P> <p> public class server {</P> <p> serversocket; <br/> serverlistenthread something; <br/> node client; <br/> onlinelist online; <br/> Public void Init () {</P> <p> try {<br/> socket = new serversocket (5126); <br/> // system. out. println ("port (5126) opened successfully"); <br/> online = new onlinelist (); <br/>…… = new serverlistenth Read (socket, online); <br/> something. start (); <br/>}catch (exception ERR) {<br/> // system. out. println ("port opening failed! "); <Br/> // system. out. println (err. getmessage (); <br/> system. exit (1); <br/>}</P> <p >}< br/> Public static void main (string ARGs []) {<br/> server Server = new server (); <br/> server. init (); <br/>}</P> <p> class serverlistenthread extends thread {<br/> serversocket; <br/> node client; <br/> onlinelist online; <br/> serverclientthread clientthread; <br/> Public serverlistenthread (serversocket socket, Onlinelist online) {<br/> This. socket = socket; <br/> This. online = online; <br/>}< br/> Public void sendmsgtoall (string MSG) {<br/> node nodetemp = online. root. next; <br/> try {<br/> while (nodetemp! = NULL) {<br/> nodetemp. out. write (0); <br/> nodetemp. out. flush (); <br/> nodetemp. out. writeobject (MSG); <br/> nodetemp. out. flush (); <br/> nodetemp = nodetemp. next; <br/>}< br/>} catch (exception e) {<br/> system. out. println (E. tostring (); <br/>}< br/> Public void run () {<br/> while (! Socket. isclosed () {<br/> client = new node (); <br/> try {<br/> // system. out. println ("Start listening"); <br/> client. socket = socket. accept (); <br/> // system. out. println ("customer connection"); <br/> client. out = new objectoutputstream (client. socket. getoutputstream (); <br/> client. out. flush (); <br/> client. in = new objectinputstream (client. socket. getinputstream (); <br/> client. username = client. in. readobject (). tostring (); <br/> online. add (C Lient); <br/> sendmsgtoall (client. username + "online"); <br/> sendmsgtoall ("online users:" + online. count); <br/> sendmsgtoall (online. showall (); <br/> clientthread = new serverclientthread (online, client); <br/> clientthread. start (); <br/>}catch (exception ERR) {<br/> system. out. println (err. getmessage ()); <br/>}</P> <p> class serverclientthread extends thread {<br/> node client, tempnode; <br/> onlinelist Online; <br/> INT system; <br/> string touser; <br/> Public serverclientthread (onlinelist online, node client) {<br/> This. client = client; <br/> This. online = online; <br/>}< br/> Public void run () {<br/> try {<br/> // start listening; <br/> while (! Client. socket. isclosed () {<br/> system = client. in. read (); <br/> system. out. println ("system =" + system); <br/> If (system = 1) {<br/> touser = client. in. readobject (). tostring (); <br/> system. out. println ("touser =" + touser); <br/> tempnode = online. find (touser); <br/> system. out. println ("temp =" + tempnode); <br/> If (tempnode! = NULL) {<br/> tempnode. out. write (1); <br/> tempnode. out. flush (); <br/> tempnode. out. writeobject (touser); <br/> tempnode. out. flush (); <br/> system. out. print ("send 1"); <br/> tempnode. out. writeobject (client. in. readobject (); <br/> tempnode. out. flush (); <br/> system. out. print ("Send 2"); <br/> tempnode. out. writeobject (client. in. readobject (); <br/> tempnode. out. flush (); <br/> system. out. print ("Send 3"); <br/>}< br/> else {<br/> client. out. write (0); <br/> client. out. flush (); <br/> client. out. writeobject ("system message: the user is not online"); <br/> client. out. flush (); <br/> client. in. readobject (); <br/> client. in. readobject (); <br/>}< br/> else if (system = 0) {<br/> client. out. write (0); <br/> client. out. flush (); <br/> client. out. writeobject ("system message"); <br/> client. out. flush (); <br/>}< br/> else {<br/> system. out. print (client. in. readobject (). tostring (); <br/>}< br/> // system. out. println ("send"); <br/> // client. out. flush (); <br/>}< br/>}catch (exception ERR) {<br/> system. out. println (err. tostring (); <br/> online. del (client); <br/>}< br/>