亲宝软件园·资讯

展开

Spring WebSocket 404错误 Spring WebSocket 404错误的解决办法

Silent_Paladin 人气:1
想了解Spring WebSocket 404错误的解决办法的相关内容吗,Silent_Paladin在本文为您仔细讲解Spring WebSocket 404错误的相关知识和一些Code实例,欢迎阅读和指正,我们先划重点:Spring,WebSocket,404,下面大家一起来学习吧。

近来学习 Spring WebSocket 时按照 Spring IN ACTION 中示例编写代码,运行时浏览器报404 错误

WebSocket connection to 'ws://localhost/websocket/marco' failed: Error during WebSocket handshake: Unexpected response code: 404

按照 Spring IN ACTION 中步骤:
首先,继承 AbstractWebSocketHandler,重载以下 3 个方法:
- handleTextMessage – 处理文本类型消息
- afterConnectionEstablished – 新连接建立后调用
- afterConnectionClosed – 连接关闭后调用

import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.AbstractWebSocketHandler;

public class MarcoHandler extends AbstractWebSocketHandler {

 protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
  System.out.println("Received message: " + message.getPayload());
  Thread.sleep(2000);
  session.sendMessage(new TextMessage("Polo!"));
 }

 @Override
 public void afterConnectionEstablished(WebSocketSession session) {
  System.out.println("Connection established!");
 }

 @Override
 public void afterConnectionClosed(WebSocketSession session, CloseStatus status) {
  System.out.println("Connection closed. Status: " + status);
 }

}

其次,使用 JavaConfig 启用 WebSocket 并映射消息处理器

import org.springframework.context.annotation.Bean;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;

@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {

 @Override
 public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
  registry.addHandler(marcoHandler(), "/marco");
 }

 @Bean
 public MarcoHandler marcoHandler() {
  return new MarcoHandler();
 }

}

最后,编写前端 JS 代码发起连接请求及后续消息交互

var url = 'ws://' + window.location.host + '/websocket/marco';
var sock = new WebSocket(url);

sock.onopen = function() {
 console.log('Opening');
 sock.send('Marco!');
};

sock.onmessage = function(e) {
 console.log('Received Message: ', e.data);
 setTimeout(function() {
  sayMarco()
 }, 2000);
};

sock.onclose = function() {
 console.log('Closing');
};

function sayMarco() {
 console.log('Sending Marco!');
 sock.send('Marco!');
}

部署后打开浏览器运行,直接报 404 错误

上网搜索了一晚上解决方案,包括参考 stackoverflow.com 上的经验都未解决该问题,直到查看到以下文章:
Spring集成webSocket页面访问404问题的解决方法

在此自己也做个记录避免以后遗忘。

WebSocket 实质上借用 HTTP 请求进行握手,启用 Spring WebSocket 需要在 org.springframework.web.servlet.DispatcherServlet 里配置拦截此请求

以下是解决步骤:

首先,修改 WebSocketConfig 类定义,在类上添加 @Configuration 注解,表明该类以 JavaConfig 形式用作 bean 定义的源(相当于 XML 配置中的 <beans> 元素)。

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;

@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {

 @Override
 public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
  registry.addHandler(marcoHandler(), "/marco");
 }

 @Bean
 public MarcoHandler marcoHandler() {
  return new MarcoHandler();
 }

}

其次,使用 JavaConfig 配置 DispatcherServlet,继承org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer ,重载以下 3 个方法:
- getRootConfigClasses – 返回带有 @Configuration 注解的类将会用来配置 ContextLoaderListener 创建的应用上下文中的 bean
- getServletConfigClasses – 返回带有 @Configuration 注解的类将会用来定义 DispatcherServlet 应用上下文中的 bean
- getServletMappings – 将一个或多个路径映射到 DispatcherServlet 上

实际上,如果只需要 Spring WebSocket 生效,则只需要在 getServletConfigClasses 方法中返回用来定义 DispatcherServlet 应用上下文中的 bean

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class WebSocketInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

 @Override
 protected Class<?>[] getRootConfigClasses() {
  return null;
 }

 @Override
 protected Class<?>[] getServletConfigClasses() {
  return new Class<?>[] {WebSocketConfig.class};
 }

 @Override
 protected String[] getServletMappings() {
  return new String[] {"/"};
 }

}

重新部署后代开浏览器运行成功

客户端消息

服务器消息

加载全部内容

相关教程
猜你喜欢
用户评论