servlet中加入socket

最新推荐文章于 2022-09-16 23:17:15 发布

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最新推荐文章于 2022-09-16 23:17:15 发布

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分类专栏： java

本文链接：https://blog.youkuaiyun.com/u013074465/article/details/50189387

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本文介绍了一个简单的Servlet与Socket通信的实例。通过创建一个Servlet，它不仅能够接收来自客户端的Socket消息，还能每秒刷新页面显示当前时间。该示例包括了完整的Java代码和web.xml配置。

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对于web是一个白痴级的人，现在用到了前端的知识，只能边学边用，做做笔记。

现在需要在servlet中写一个socket与其他程序通信。一个非常简单的demo：控制台输出客户端发来的信息，这个servlet还每秒刷新一次网页，输出时间。

如下是servlet的源码HelloWorld.java：

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.net.*;

class SocketServer extends Thread
{
	private Socket socket;
	public SocketServer(Socket socket)
	{
		this.socket = socket;
	}

	public void run()
	{
		String output = "";
		try
		{
			BufferedReader bfr = new BufferedReader(new InputStreamReader(socket.getInputStream()));
			PrintWriter pw = new PrintWriter(socket.getOutputStream());
			String line = null;
			line = bfr.readLine();
			output = "server send====================";
			pw.println(output);
			pw.flush();
			bfr.close();
			pw.close();
			socket.close();
		}
		catch (IOException ioex)
		{
			ioex.printStackTrace();
		}
	}
}

public class HelloWorld extends HttpServlet {
	private String message;

	public void init() throws ServletException
	{
		System.out.println("=================hello world=================");
		new Thread() {
			public void run()
			{
				try
				{
					ServerSocket server = new ServerSocket(30000);
					Socket socket = null;
					while (true)
					{
						socket = server.accept();
						SocketServer ss = new SocketServer(socket);
						ss.start();
					}
				}
				catch (IOException ex)
				{
					System.out.println(ex.getMessage());
				}
			}
		}.start();
		System.out.println("_______________________hello world___________________________");
  }
  
  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
            throws ServletException, IOException
  {
      response.setIntHeader("Refresh", 1);
      response.setContentType("text/html");
	  response.setHeader("content-type","text/html;charset=gb2312");

      Calendar calendar = new GregorianCalendar();
      String am_pm;
      int hour = calendar.get(Calendar.HOUR);
      int minute = calendar.get(Calendar.MINUTE);
      int second = calendar.get(Calendar.SECOND);
      if(calendar.get(Calendar.AM_PM) == 0)
        am_pm = "AM";
      else
        am_pm = "PM";
 
      String CT = hour+":"+ minute +":"+ second +" "+ am_pm;
    
      PrintWriter out = response.getWriter();
      String title = "使用 Servlet 自动刷新页面";
      String docType =
      "<!doctype html public \"-//w3c//dtd html 4.0 " +
      "transitional//en\">\n";
      out.println(docType +
        "<html>\n" +
        "<head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/> <title>" + title + "</title></head>\n"+
        "<body bgcolor=\"#f0f0f0\">\n" +
        "<h1 align=\"center\">" + title + "</h1>\n" +
        "<p>当前时间是：" + CT + "</p>\n");
  }
  
  public void doPost(HttpServletRequest request,
                     HttpServletResponse response)
      throws ServletException, IOException {
     doGet(request, response);
  }

  
  public void destroy()
  {
  }
}

web.xml配置：

<servlet>
        <servlet-name>HelloWorld</servlet-name>
        <servlet-class>HelloWorld</servlet-class>
		<load-on-startup>0</load-on-startup> 
    </servlet>

    <servlet-mapping>
        <servlet-name>HelloWorld</servlet-name>
        <url-pattern>/HelloWorld</url-pattern>
    </servlet-mapping>

这样，通过socket，这个servlet可以接收到其他程序第一次发来的socket消息了。

参考：http://blog.youkuaiyun.com/veverrr/article/details/7085636