WebSocket接口中有一个直接发送对象给页面的方法:
arg0) throws
如果直接使用
client.session.getBasicRemote().sendObject(obj);
就会出现以下错误:
javax.websocket.EncodeException: No encoder specified for object of class [class org.ywzn.po.Messagepojo]
解决的方法有一个，就是需要一个编码器，具体步骤如下:
1、自定义的一个普通Java实体类，这个没有什么特别，一些属性、set、get、toString方法而已
package org.ywzn.po;import java.io.Serializable;/** * 发送给ActiveMQ的实体类 * * @author 夏小雪 日期:2015年6月11日 时间:下午12:14:18 */public class Messagepojo implements Serializable {private static final long serialVersionUID = -6451812593150428369L;private String sourse;// 信息来源private String messageType;// 消息类型private String msgContent;// 消息内容private String target;// 发送目的地private String infoSourceIP;// 信息来源ipprivate String createtime;// 消息保存时间private String otherContent;// 其他信息public Messagepojo() {super();}public Messagepojo(String sourse, String messageType, String msgContent,String target, String infoSourceIP, String createtime,String otherContent) {super();this.sourse = sourse;this.messageType = messageType;this.msgContent = msgContent;this.target = target;this.infoSourceIP = infoSourceIP;this.createtime = createtime;this.otherContent = otherContent;}public String getSourse() {return sourse;}public void setSourse(String sourse) {this.sourse = sourse;}public String getMessageType() {return messageType;}public void setMessageType(String messageType) {this.messageType = messageType;}public String getMsgContent() {return msgContent;}public void setMsgContent(String msgContent) {this.msgContent = msgContent;}public String getTarget() {return target;}public void setTarget(String target) {this.target = target;}public String getInfoSourceIP() {return infoSourceIP;}public void setInfoSourceIP(String infoSourceIP) {this.infoSourceIP = infoSourceIP;}public String getCreatetime() {return createtime;}public void setCreatetime(String createtime) {this.createtime = createtime;}public String getOtherContent() {return otherContent;}public void setOtherContent(String otherContent) {this.otherContent = otherContent;}@Overridepublic String toString() {return "Messagepojo [sourse=" + sourse + ", messageType=" + messageType+ ", msgContent=" + msgContent + ", target=" + target+ ", infoSourceIP=" + infoSourceIP + ", createtime="+ createtime + ", otherContent=" + otherContent + "]";}}2、编写自己的解码器
在encode()的这个方法内，可以自定义要返回的值，，这里我需要的是Java对象转成的Json格式字符串，用的是一个自己写的工具类，这个可以根据自己的需求自定义，这里只给各位做一个参考。
package org.ywzn.websocket;import javax.websocket.EncodeException;import javax.websocket.Encoder;import javax.websocket.EndpointConfig;import org.ywzn.po.Messagepojo;import org.ywzn.util.Java2Json;import com.sdicons.json.mapper.MapperException;/** * definition for our encoder * * @编写人: 夏小雪 日期:2015年6月14日 时间:上午11:58:23 */public class ServerEncoder implements Encoder.Text<Messagepojo> {@Overridepublic void destroy() {// TODO Auto-generated method stub}@Overridepublic void init(EndpointConfig arg0) {// TODO Auto-generated method stub}@Overridepublic String encode(Messagepojo messagepojo) throws EncodeException {try {return Java2Json.JavaToJson(messagepojo, false);} catch (MapperException e) {// TODO Auto-generated catch blocke.printStackTrace();return null;}}}3、WebSocket的服务终端
重要的地方只有一个:
@ServerEndpoint(value = "/websocket/news", encoders = { ServerEncoder.class })
encoders加入了刚刚自定义的解码类,这样就可以直接使用client.session.getBasicRemote().sendObject(obj);传入对象了。
package org.ywzn.websocket;import java.io.IOException;import java.text.SimpleDateFormat;import java.util.Date;import java.util.HashMap;import java.util.Map;import java.util.concurrent.atomic.AtomicInteger;import javax.websocket.EncodeException;import javax.websocket.EndpointConfig;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.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.ywzn.activemq.Sender;import org.ywzn.po.Messagepojo;import org.ywzn.util.Java2Json;import com.sdicons.json.mapper.MapperException;/** * 消息协查中心 WebSocket 消息推送服务类 * * @author 夏小雪 日期:2015年6月10日 时间:上午9:48:59 */@ServerEndpoint(value = "/websocket/news", encoders = { ServerEncoder.class })public class NewsAnnotation {private static final Log log = LogFactory.getLog(NewsAnnotation.class);private static final String GUEST_PREFIX = "Guest";private static final AtomicInteger connectionIds = new AtomicInteger(0);private static final Map<String, Object> connections = new HashMap<String, Object>();private static final String[] GUESTNAME = { "高勇", "梁肇辉", "李燕","梁晓晓", "蔡俊", "张新", "高帅", "夏小雪", "彭连英", "刘剑" };private String nickname;private Session session;// 当前用户idprivate Integer id;// private HttpSession httpSession;public NewsAnnotation() {// nickname = GUEST_PREFIX + connectionIds.getAndIncrement();// int index = connectionIds.getAndIncrement();// if (index >= 8) {// connectionIds.set(0);// }// nickname = GUESTNAME[index];}@OnOpenpublic void start(Session session, EndpointConfig config) {// Set<Entry<String, Object>> entrySet =// config.getUserProperties().entrySet();// for (Iterator<Entry<String, Object>> iterator = entrySet.iterator();// iterator.hasNext();) {// String key = iterator.next().getKey();// System.out.println("[EndpointConfig–>key]:" + key);// System.out.println("value–>" + config.getUserProperties().get(key));// PojoMethodMapping p =// (PojoMethodMapping)config.getUserProperties().get(key);// System.out.println("p.getWsPath()–>" + p.getWsPath());// }// String negotiatedSubprotocol = session.getNegotiatedSubprotocol();// System.out.println("[getAuthority]:" +// session.getRequestURI().getAuthority());// System.out.println("[getFragment]:" +// session.getRequestURI().getFragment());// System.out.println("[getPath]:" + session.getRequestURI().getPath());// System.out.println("[getPort]:" + session.getRequestURI().getPort());// System.out.println("[getQuery]:" +// session.getRequestURI().getQuery());// System.out.println("[getRawUserInfo]:" +// session.getRequestURI().getRawAuthority());// System.out.println("[getRawFragment]:" +// session.getRequestURI().getRawFragment());// System.out.println("[getHost]:" + session.getRequestURI().getHost());// System.out.println("[getRawUserInfo]:" +// session.getRequestURI().getRawUserInfo());// System.out.println("[getScheme]:" +// session.getRequestURI().getScheme());// System.out.println("[getSchemeSpecificPart]:" +// session.getRequestURI().getSchemeSpecificPart());// System.out.println("[getUserInfo]:" +// session.getRequestURI().getUserInfo());// System.out.println("[negotiatedSubprotocol]:" +// negotiatedSubprotocol);// Set<Entry<String, String>> entrySet =// session.getPathParameters().entrySet();// for(Iterator<Entry<String, String>> iter =// entrySet.iterator();iter.hasNext();){// System.out.println("[getKey]:" + iter.next().getKey());// }// System.out.println("[session.getProtocolVersion()]:" +// session.getProtocolVersion());this.session = session;id = Integer.parseInt(this.session.getId());if (id > 8) {id = 0;}nickname = GUESTNAME[id];System.out.println("当前用户的ID是:" + id + "\n用户姓名是:" + nickname);connections.put(nickname, this);String message = String.format("* %s %s", nickname, "已经登录消息协查中心.");// 群发broadcast(message, "all");// 发送登录的消息给activemqSender.sendMsg("login:" + nickname);}@OnClosepublic void end() {System.out.println("消息中心连接关闭.");connections.remove(this);String message = String.format("* %s %s", nickname, "has disconnected.");// 群发// broadcast(message, "all");// 发送登录的消息给activemq// Sender.sendMsg("quit:" + nickname);}/** * 消息发送触发方法 * * @param message */@OnMessagepublic void incoming(String message) {System.out.println("Java收到了网页[" + this.nickname + "]的消息[message]:"+ message);// Never trust the clientString filteredMessage = String.format("%s: %s", nickname,HTMLFilter.filter(message.toString()));// 发送登录的消息给activemqMessagepojo messagepojo = new Messagepojo(this.nickname, "用户对话",message, "all", this.id.toString(), new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date()), "");try {String javaToJson = Java2Json.JavaToJson(messagepojo, false);System.out.println("发送信息:" + javaToJson);Sender.sendMsg("Message–>" + javaToJson);} catch (MapperException e) {// TODO Auto-generated catch blocke.printStackTrace();}// Sender.sendMsg("sendMsg:" + message);// broadcast(filteredMessage, "all");}@OnErrorpublic void onError(Throwable t) throws Throwable {log.error("Chat Error: " + t.toString(), t);}/** * 消息发送方法 author 夏小雪 日期:2015年6月10日 时间:上午9:49:45 * * @param msg *发送的内容 * @param user *发给指定的用户,如果要发给所有的则填""或"all" */private static void broadcast(String msg, String user) {// 是否群发if (user == null || "all".equals(user) || "".equals(user)) {sendAll(msg);} else {sendUser(msg, user);}}/** * 向所有用户发送 author 夏小雪 日期:2015年6月10日 时间:上午9:50:34 * * @param msg */public static void sendAll(String msg) {for (String key : connections.keySet()) {NewsAnnotation client = null;try {client = (NewsAnnotation) connections.get(key);synchronized (client) {if (client.session.isOpen()) { // 如果这个session是打开的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.");// 群发broadcast(message, "all");}}}/** * 向所有用户发送 * * @编写人: 夏小雪 日期:2015年6月14日 时间:上午11:14:46 * @param obj *对象 */public static void sendAll(Object obj) {for (String key : connections.keySet()) {NewsAnnotation client = null;try {client = (NewsAnnotation) connections.get(key);synchronized (client) {if (client.session.isOpen()) { // 如果这个session是打开的client.session.getBasicRemote().sendObject(obj);}}} 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.");// 群发broadcast(message, "all");} catch (EncodeException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}/** * 向指定用户发送消息 author 夏小雪 日期:2015年6月10日 时间:上午9:50:45 * * @param msg *内容 * @param user *用户 */public static void sendUser(String msg, String user) {// 获取要发送的用户NewsAnnotation c = (NewsAnnotation) connections.get(user);try {if (c != null) {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.");// 群发broadcast(message, "all");}}}我这里已经搭建了WebSocket和ActiveMQ的框架，下面截图看下效果:在乎的是看风景的心情，旅行不会因为美丽的风景终止。
