怎么在java中使用WebSocket實(shí)現(xiàn)一個(gè)聊天消息推送功能？相信很多沒有經(jīng)驗(yàn)的人對(duì)此束手無策，為此本文總結(jié)了問題出現(xiàn)的原因和解決方法，通過這篇文章希望你能解決這個(gè)問題。
十年的密云網(wǎng)站建設(shè)經(jīng)驗(yàn)，針對(duì)設(shè)計(jì)、前端、開發(fā)、售后、文案、推廣等六對(duì)一服務(wù)，響應(yīng)快，48小時(shí)及時(shí)工作處理。網(wǎng)絡(luò)營銷推廣的優(yōu)勢是能夠根據(jù)用戶設(shè)備顯示端的尺寸不同，自動(dòng)調(diào)整密云建站的顯示方式，使網(wǎng)站能夠適用不同顯示終端，在瀏覽器中調(diào)整網(wǎng)站的寬度，無論在任何一種瀏覽器上瀏覽網(wǎng)站，都能展現(xiàn)優(yōu)雅布局與設(shè)計(jì)，從而大程度地提升瀏覽體驗(yàn)。創(chuàng)新互聯(lián)從事“密云網(wǎng)站設(shè)計(jì)”,“密云網(wǎng)站推廣”以來，每個(gè)客戶項(xiàng)目都認(rèn)真落實(shí)執(zhí)行。
環(huán)境：
JDK.1.7.0_51
apache-tomcat-7.0.53
java jar包：tomcat-coyote.jar、tomcat-juli.jar、websocket-api.jar
ChatAnnotation消息發(fā)送類：
重慶分公司
重慶分公司
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import com.util.HTMLFilter;
/**
* WebSocket 消息推送服務(wù)類
* @author 胡漢三
*
* 2014-11-18 下午7:53:13
*/
@ServerEndpoint(value = "/websocket/chat")
public class ChatAnnotation {
private static final Log log = LogFactory.getLog(ChatAnnotation.class);
private static final String GUEST_PREFIX = "Guest";
private static final AtomicInteger connectionIds = new AtomicInteger(0);
private static final Map connections = new HashMap();
private final String nickname;
private Session session;
public ChatAnnotation() {
nickname = GUEST_PREFIX + connectionIds.getAndIncrement();
}
@OnOpen
public void start(Session session) {
this.session = session;
connections.put(nickname, this);
String message = String.format("* %s %s", nickname, "has joined.");
broadcast(message);
}
@OnClose
public void end() {
connections.remove(this);
String message = String.format("* %s %s",
nickname, "has disconnected.");
broadcast(message);
}
/**
* 消息發(fā)送觸發(fā)方法
* @param message
*/
@OnMessage
public void incoming(String message) {
// Never trust the client
String filteredMessage = String.format("%s: %s",
nickname, HTMLFilter.filter(message.toString()));
broadcast(filteredMessage);
}
@OnError
public void onError(Throwable t) throws Throwable {
log.error("Chat Error: " + t.toString(), t);
}
/**
* 消息發(fā)送方法
* @param msg
*/
private static void broadcast(String msg) {
if(msg.indexOf("Guest0")!=-1){
sendUser(msg);
} else{
sendAll(msg);
}
}
/**
* 向所有用戶發(fā)送
* @param msg
*/
public static void sendAll(String msg){
for (String key : connections.keySet()) {
ChatAnnotation client = null ;
try {
client = (ChatAnnotation) connections.get(key);
synchronized (client) {
client.session.getBasicRemote().sendText(msg);
}
} catch (IOException e) {
log.debug("Chat Error: Failed to send message to client", e);
connections.remove(client);
try {
client.session.close();
} catch (IOException e1) {
// Ignore
}
String message = String.format("* %s %s",
client.nickname, "has been disconnected.");
broadcast(message);
}
}
}
/**
* 向指定用戶發(fā)送消息
* @param msg
*/
public static void sendUser(String msg){
ChatAnnotation c = (ChatAnnotation)connections.get("Guest0");
try {
c.session.getBasicRemote().sendText(msg);
} catch (IOException e) {
log.debug("Chat Error: Failed to send message to client", e);
connections.remove(c);
try {
c.session.close();
} catch (IOException e1) {
// Ignore
}
String message = String.format("* %s %s",
c.nickname, "has been disconnected.");
broadcast(message);
}
}
} HTMLFilter工具類：
/**
* HTML 工具類
*
* @author 胡漢三
*/
public final class HTMLFilter {
public static String filter(String message) {
if (message == null)
return (null);
char content[] = new char[message.length()];
message.getChars(0, message.length(), content, 0);
StringBuilder result = new StringBuilder(content.length + 50);
for (int i = 0; i < content.length; i++) {
switch (content[i]) {
case '<':
result.append("<");
break;
case '>':
result.append(">");
break;
case '&':
result.append("&");
break;
case '"':
result.append(""");
break;
default:
result.append(content[i]);
}
}
return (result.toString());
}
}頁面：