WebSocket簡介
目的
HTML5 WebSocket設(shè)計出來的目的就是取代輪詢和長連接，使客戶端瀏覽器具備像C/S框架下桌面系統(tǒng)的即時通訊能力，實(shí)現(xiàn)了瀏覽器和服務(wù)器全雙工通信，建立在TCP之上，雖然WebSocket和HTTP一樣通過TCP來傳輸數(shù)據(jù)，但WebSocket可以主動的向?qū)Ψ桨l(fā)送或接收數(shù)據(jù)，就像Socket一樣；并且WebSocket需要類似TCP的客戶端和服務(wù)端通過握手連接，連接成功后才能互相通信。
優(yōu)點(diǎn)
雙向通信、事件驅(qū)動、異步、使用ws或wss協(xié)議的客戶端能夠真正實(shí)現(xiàn)意義上的推送功能。
缺點(diǎn)
少部分瀏覽器不支持。
示例
社交聊天（微信、QQ）、彈幕、多玩家玩游戲、協(xié)同編輯、股票基金實(shí)時報價、體育實(shí)況更新、視頻會議/聊天、基于位置的應(yīng)用、在線教育、智能家居等高實(shí)時性的場景。
WebSocket請求響應(yīng)客戶端服務(wù)器交互圖
請求響應(yīng)客戶端服務(wù)器交互圖.png
WebSocket方式減少了很多TCP打開和關(guān)閉連接的操作，WebSocket的資源利用率高。
java WebSocket實(shí)現(xiàn)
Oracle 發(fā)布的 java 的 WebSocket 的規(guī)范是 JSR356規(guī)范 ,Tomcat從7.0.27開始支持WebSocket，從7.0.47開始支持JSR-356。
websocket簡單實(shí)現(xiàn)分為以下幾個步驟：
- 添加websocket庫
- 編寫后臺代碼
- 編寫前端代碼。
添加websocket整合springboot依賴
<!--websocket-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
后臺代碼實(shí)現(xiàn)
配置類
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;
/**
* 首先注入一個ServerEndpointExporterBean,該Bean會自動注冊使用@ServerEndpoint注解申明的websocket endpoint
* 鏈接：https://www.imooc.com/article/70702?block_id=tuijian_wz
*/
@Configuration
public class WebSocketConfig {
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
}
websocket接口實(shí)現(xiàn)
@ServerEndpoint(value = "/websocket") //接受websocket請求路徑
@Component
public class PoundWebSocket {
private Logger logger = LoggerFactory.getLogger(this.getClass());
/**
* 保存所有在線socket連接
*/
private static Map<String, PoundWebSocket> webSocketMap = new LinkedHashMap<>();
/**
* 記錄當(dāng)前在線數(shù)目
*/
private static int count = 0;
/**
* 當(dāng)前連接（每個websocket連入都會創(chuàng)建一個MyWebSocket實(shí)例
*/
private Session session;
/**
* 創(chuàng)建監(jiān)聽串口
*/
private static SerialPort serialPort = null;
/**
* 創(chuàng)建監(jiān)聽器
*/
private static SerialPortEventListener serialPortEventListener = null;
/**
* 監(jiān)聽串口
*/
private static String PORT_NAME;
/**
* 監(jiān)聽串口波特率
*/
private static int BAUD_RATE;
/**
* 數(shù)據(jù)位
*/
private static int DATA_BITS;
/**
* 停止位
*/
private static int STOP_BITS;
/**
* 奇偶位
*/
private static int PARITY;
/**
* 地磅型號
*/
private static String MODEL;
private static IPoundInfoService poundInfoService;
private static ApplicationContext applicationContext;
public static void setApplicationContext(ApplicationContext applicationContext) {
PoundWebSocket.applicationContext = applicationContext;
}
private static StringBuffer stringBuffer = new StringBuffer();
/**
* 處理連接建立
*
* @param session
*/
@OnOpen
public void onOpen(Session session) {
if (poundInfoService == null) {
poundInfoService = applicationContext.getBean(IPoundInfoService.class);
}
//獲取地磅信息
PoundInfo poundInfo = poundInfoService.findOne();
PORT_NAME = poundInfo.getSerialPort();
BAUD_RATE = poundInfo.getBaudRate();
MODEL = poundInfo.getModel();
DATA_BITS = poundInfo.getDataBits() != null ? poundInfo.getDataBits() : SerialPort.DATABITS_8;
STOP_BITS = poundInfo.getStopBits() != null ? poundInfo.getStopBits() : SerialPort.STOPBITS_1;
PARITY = poundInfo.getParity() != null ? poundInfo.getParity() : SerialPort.PARITY_NONE;
this.session = session;
webSocketMap.put(session.getId(), this);
addCount();
// logger.info("新的連接加入：{}", session.getId());
try {
//確保串口已被關(guān)閉，未關(guān)閉會導(dǎo)致重新監(jiān)聽串口失敗
if (serialPort != null) {
SerialPortUtil.closePort(serialPort);
serialPort = null;
}
//創(chuàng)建串口 COM5位串口名稱 9600波特率
if (serialPort == null && StringUtils.isNotEmpty(PORT_NAME) && StringUtils.isNotEmpty(MODEL)) {
serialPort = SerialPortUtil.openPort(PORT_NAME, BAUD_RATE, DATA_BITS, PARITY, STOP_BITS);
// logger.info("創(chuàng)建串口：{}", serialPort);
//設(shè)置串口監(jiān)聽
SerialPortUtil.addListener(serialPort, new SerialPortEventListener() {
@Override
public void serialEvent(SerialPortEvent serialPortEvent) {
if (serialPortEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
try {
//讀取串口數(shù)據(jù)
byte[] bytes = SerialPortUtil.readFromPort(serialPort);
//根據(jù)型號解析字符串
switch (MODEL) {
case PoundConstant.MODEL_XK_3190:
parsingString1(bytes);
break;
case PoundConstant.MODEL_XK_3190_10:
parsingString2(bytes);
break;
case PoundConstant.MODEL_D_2008:
parsingString1(bytes);
break;
case PoundConstant.MODEL_DK_3230_D_6:
parsingString3(bytes);
break;
case PoundConstant.MODEL_D_2009_F:
parsingString4(bytes);
break;
default:
String value = String.valueOf(Integer.valueOf(new String(bytes, "GB2312")) - RandomUtil.randomInt(1000, 10000));
sendMessageToAll(value);
}
// System.out.println("收到的數(shù)據(jù)：" + new String(bytes, "GB2312") + "----" + new Date());
} catch (ReadDataFromSerialPortFailure readDataFromSerialPortFailure) {
logger.error(readDataFromSerialPortFailure.toString());
} catch (SerialPortInputStreamCloseFailure serialPortInputStreamCloseFailure) {
logger.error(serialPortInputStreamCloseFailure.toString());
} catch (UnsupportedEncodingException e) {
logger.error(e.toString());
} catch (IOException e) {
logger.error(e.toString());
}
}
}
});
}
} catch (SerialPortParameterFailure serialPortParameterFailure) {
logger.error(serialPortParameterFailure.toString());
} catch (NotASerialPort notASerialPort) {
logger.error(notASerialPort.toString());
} catch (NoSuchPort noSuchPort) {
logger.error(noSuchPort.toString());
} catch (PortInUse portInUse) {
logger.error(portInUse.toString());
} catch (TooManyListeners tooManyListeners) {
logger.error(tooManyListeners.toString());
}
}
/**
* 解析字符串 方法1
*
* @param bytes 獲取的字節(jié)碼
*/
private void parsingString1(byte[] bytes) {
StringBuffer sb = new StringBuffer();
//將ASCII碼轉(zhuǎn)成字符串
for (int i = 0; i < bytes.length; i++) {
sb.append((char) Integer.parseInt(String.valueOf(bytes[i])));
}
//解析字符串
String[] strs = sb.toString().trim().split("\\+");
int weight = 0;
for (int j = 0; j < strs.length; j++) {
if (strs[j].trim().length() >= 6) {
weight = Integer.parseInt(strs[j].trim().substring(0, 6));
//發(fā)送數(shù)據(jù)
sendMessageToAll(String.valueOf(weight));
break;
}
}
}
/**
* 解析字符串 方法2
*
* @param bytes 獲取的字節(jié)碼
*/
private void parsingString2(byte[] bytes) {
StringBuffer sb = new StringBuffer();
//將ASCII碼轉(zhuǎn)成字符串
for (int i = 0; i < bytes.length; i++) {
sb.append((char) Integer.parseInt(String.valueOf(bytes[i])));
}
//解析字符串
String[] strs = sb.toString().trim().split("\\+");
double weight = 0;
for (int j = 0; j < strs.length; j++) {
if (strs[j].trim().length() >= 6) {
weight = Double.parseDouble(strs[j].trim().substring(0, 6)) / 10;
//發(fā)送數(shù)據(jù)
sendMessageToAll(String.valueOf(weight));
break;
}
}
}
/**
* 解析字符串 方法3
*
* @param bytes 獲取的字節(jié)碼
*/
private void parsingString3(byte[] bytes) {
StringBuffer sb = new StringBuffer();
//將ASCII碼轉(zhuǎn)成字符串
for (int i = 0; i < bytes.length; i++) {
sb.append((char) Integer.parseInt(String.valueOf(bytes[i])));
}
// logger.info("sb:" + sb.toString());
sb.reverse();
//解析字符串
String[] strs = sb.toString().trim().split("\\=");
double weight = 0;
for (int j = 0; j < strs.length; j++) {
if (strs[j].trim().length() >= 6) {
weight = Double.parseDouble(strs[j].trim());
//發(fā)送數(shù)據(jù)
sendMessageToAll(String.valueOf(weight));
break;
}
}
}
/**
* 解析字符串 方法3
*
* @param bytes 獲取的字節(jié)碼
*/
private void parsingString4(byte[] bytes) {
StringBuffer sb = new StringBuffer();
//將ASCII碼轉(zhuǎn)成字符串
for (int i = 0; i < bytes.length; i++) {
sb.append((char) Integer.parseInt(String.valueOf(bytes[i])));
}
// logger.info("sb:" + sb.reverse());
//字符串反轉(zhuǎn)
sb.reverse();
//解析字符串
String[] strs = sb.toString().trim().split("\\=");
int weight = 0;
for (int j = 0; j < strs.length; j++) {
if (strs[j].trim().length() >= 6) {
weight = Integer.parseInt(strs[j].trim().substring(0, 6));
//發(fā)送數(shù)據(jù)
sendMessageToAll(String.valueOf(weight));
break;
}
}
}
/**
* 接受消息
*
* @param message
* @param session
*/
@OnMessage
public void onMessage(String message, Session session) {
logger.info("收到客戶端{(lán)}消息：{}", session.getId(), message);
try {
this.sendMessage(message);
} catch (Exception e) {
logger.error(e.toString());
}
}
/**
* 處理錯誤
*
* @param error
* @param session
*/
@OnError
public void onError(Throwable error, Session session) {
logger.info("發(fā)生錯誤{},{}", session.getId(), error.getMessage());
}
/**
* 處理連接關(guān)閉
*/
@OnClose
public void onClose() {
webSocketMap.remove(this.session.getId());
reduceCount();
logger.info("連接關(guān)閉:{}", this.session.getId());
//連接關(guān)閉后關(guān)閉串口，下一次打開連接重新監(jiān)聽串口
if (serialPort != null) {
SerialPortUtil.closePort(serialPort);
serialPort = null;
}
}
/**
* 群發(fā)消息
*
* @param message
*/
public void sendMessageToAll(String message) {
for (int i = 0; i < webSocketMap.size(); i++) {
try {
// logger.info("session:id=" + session.getId());
this.session.getBasicRemote().sendText(message);
} catch (IOException e) {
logger.error(e.getMessage());
}
}
}
/**
* 發(fā)送消息
*
* @param message
* @throws IOException
*/
public void sendMessage(String message) throws IOException {
// logger.info("session:id=" + session.getId());
this.session.getBasicRemote().sendText(message);
}
//廣播消息
public static void broadcast() {
PoundWebSocket.webSocketMap.forEach((k, v) -> {
try {
v.sendMessage("這是一條測試廣播");
} catch (Exception e) {
}
});
}
//獲取在線連接數(shù)目
public static int getCount() {
return count;
}
//操作count，使用synchronized確保線程安全
public static synchronized void addCount() {
PoundWebSocket.count++;
}
public static synchronized void reduceCount() {
PoundWebSocket.count--;
}
}
解決websocket不能注入bean的問題
import com.yotrio.pound.sockets.PoundWebSocket;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.context.ConfigurableApplicationContext;
@ServletComponentScan
// mapper 接口類掃描包配置
@MapperScan("com.yotrio.pound.dao")
@SpringBootApplication
public class PoundClientApplication {
public static void main(String[] args) {
// 程序啟動入口
// 啟動嵌入式的 Tomcat 并初始化 Spring 環(huán)境及其各 Spring 組件
// SpringApplication.run(PoundClientApplication.class, args);
ConfigurableApplicationContext applicationContext = SpringApplication.run(PoundClientApplication.class, args);
//解決websocket不能注入bean的問題
PoundWebSocket.setApplicationContext(applicationContext);
}
}
前臺js實(shí)現(xiàn)
//websocket實(shí)現(xiàn)
var websocket;
var socketUrl = "ws://127.0.0.1:8000/websocket";
var count = 0;
if ('WebSocket' in window) {
// console.log("此瀏覽器支持websocket");
websocket = new WebSocket(socketUrl);
} else if ('MozWebSocket' in window) {
alert("此瀏覽器只支持MozWebSocket");
} else {
alert("此瀏覽器只支持SockJS");
}
websocket.onopen = function (evnt) {
// $("#tou").html("鏈接服務(wù)器成功!");
console.log("鏈接服務(wù)器成功");
};
websocket.onmessage = function (evnt) {
// console.log("event", evnt.data);
$("#currentWeight").val(evnt.data);
};
websocket.onerror = function (evnt) {
console.log("消息異常：" + evnt.data);
};
websocket.onclose = function (evnt) {
console.log("與服務(wù)器斷開了鏈接");
}
