自己手写一个简单的tomcat服务器

客官°小女子只卖身不卖艺 2022-06-01 05:10 220阅读 0赞

Tomcat服务器本质上就是一个 Server的程序，所以这里我们先写一个Server的程序和一个Socket程序，然后在对其进行改装

Server服务端的程序见下文所示

public class Server {
 
 
 	/*
 	 Tomcat其实就是一个socket编程
 	 	下面的流程中 有两个流程,
 	 	
 	 	第一个流程是 客户端请求浏览器的流程
 	 	第二个业务流程是 服务器给客户端返回数据的业务流程
 	 	
 	 	
 	 	两个业务类型不同，在这里可以抽取两个业务类 来分别抽取 两个不同的业务类
 	 	
 	 	抽取HttpRequest 和 HttpResponse 两种业务
 	 	
 	 */
 	public static void main(String[] args) {
 		
 		//发送信息的电报机
 		ServerSocket serverSocket = null;
 		Socket client = null;
 		try{
 			serverSocket = new ServerSocket( 8888 );
 			System.out.println("服务器初始化完毕，初始化的端口是 8888");
 			//这里在不断的接收客户端请求
 			while(true){
 				//服务端接收客户端的Socket连接过来
 				client = serverSocket.accept();
 				//对客户端端里面的请求信息进行处理
 				InputStream in = client.getInputStream();	
 				//定义一个读取缓冲流,主要是在InputStream流当中读取这些字节
 				byte[] buff = new byte[1024];
 				int len = in.read(buff);
 				if(len>0){
 					String msg = new String(buff,0,len);
 					System.out.println("客户端请求信息!"+"============"+msg+"============");
 					OutputStream os = client.getOutputStream();
 					SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
 					
 					//构建一个响应头信息 200 OK
 					StringBuffer sb = new StringBuffer();
 					//响应头信息
 					
 					sb.append("HTTP/1.1 200 OK\n");
 					sb.append("Content-Type: text/html;charset=UTF-8\n");
 					sb.append("cahce-control:max-age-0");
 					sb.append("Upgrade-Insecure-Requests: 1");
 					sb.append("User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36");
 					sb.append("Accept-Encoding:gzip, deflate, br");
 					sb.append("Accept-Language:zh-CN,zh;q=0.9");
 					sb.append("\r\n");
 					
 					
 					
 					
 				//响应正文
 					String html = "<html><head><title>欢迎各位同学</title></head><body> 当前时间:" +
 						"" +
 						format.format(new Date()) +
 						" 服务器回复: 大家今天有收货吗 " +
 						" 服务器回复:大家今天有收获吗" +
 						"</body></html>";
 					//把响应头和正文都连接在了一起
 					sb.append(html);
 					
 					//响应业务,
 					os.write(sb.toString().getBytes());
 					os.flush();
 					os.close();
 				}
 			}
 			
 			
 		}catch(Exception e){
 			
 		}
 	}

接下来是一个 客户端client的程序

public class Client {
    	
    	public static void main(String[] args) {
    		
    		 try {
    	         Socket s = new Socket("127.0.0.1",8888);
    	         
    	         //构建IO
    	         InputStream is = s.getInputStream();
    	         OutputStream os = s.getOutputStream();
    	         
    	         BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
    	         //向服务器端发送一条消息
    	         bw.write("测试客户端和服务器通信，服务器接收到消息返回到客户端\n");
    	         bw.flush();
    	         
    	         //读取服务器返回的消息
    	         /*
    	         
    	         BufferedReader br = new BufferedReader(new InputStreamReader(is) );
    	         
    	         String line = br.readLine();
    	         
    	         System.out.println( line );
    	         */
    	         
    	         
    	         StringBuffer sb = new StringBuffer();
    	         int len = 0;
    	         byte[] buff = new byte[1024];
    	         while( (len = is.read(buff) )!=-1 ){
    	        	 
    	        	 sb.append( new String(buff,0,len) );
    	        	 
    	         }
    	         
    	         System.out.println(  sb.toString()  );
    	         
    	         
    		 } catch (UnknownHostException e) {
    	         e.printStackTrace();
    	      } catch (IOException e) {
    	         e.printStackTrace();
    	      }
    		
    	}
    	
    }

启动服务端然后便可以看到客户端与服务器端互相通信已经畅通

然后考虑到tomcat中在实现其功能的时候需要将其业务拆分，拆分成  处理请求的一部分和返回响应的一部分，所以这里对代码进行改进，新建一个Server2.java，项目的目录结构如下图所示：

![SouthEast][]

Server2.java代码

package com.zwz;
    
    
    import java.io.BufferedReader;
    import java.io.BufferedWriter;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.io.OutputStream;
    import java.io.OutputStreamWriter;
    import java.net.ServerSocket;
    import java.net.Socket;
    import java.text.SimpleDateFormat;
    import java.util.Date;
     
    public class Server2 {
    	
    	static SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    	
    	
       public static void main(String[] args) {
          try {
         
        	  ServerSocket ss = new ServerSocket(8888);
    	      System.out.println("启动服务器....8888端口");
        	  
        	  while(true){
    	    	 
    	         Socket s = ss.accept();
    	         System.out.println("客户端:"+s.getInetAddress().getLocalHost()+"已连接到服务器");
    	         
    	         BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));
    	        
    	         HttpRequest request = new HttpRequest( s.getInputStream() );
    	         
    	         String requesturi = request.getUri();
    	         
    	         System.out.println("请求路径是:"+requesturi);
    	         
    	         HttpResponse response = new HttpResponse(s.getOutputStream());
    	       
    	         
    	         //if(isStatic(requesturi)){
    	         	response.writeFile(requesturi);
    	         //}
    	         
    	         s.close();
        	  }
          } catch (IOException e) {
             e.printStackTrace();
          }
       }
       
       
       //静态资源的重复获取需要通过过滤
       public static boolean isStatic( String uri ){
    	   
    	   boolean isStatic = false;
    	   
    	   String []suffixs = {"html","css","js","jpg","png","gif","bmp"};
    
    	   for( String suffix : suffixs){
    		   if(uri.endsWith("."+suffix)){
    			   isStatic = true;
    			   break;
    		   }
    	   }
    	   return isStatic;
       }
       
    }

HttpReuqest.java代码：

package com.zwz;
    
    import java.io.IOException;
    import java.io.InputStream;
    
    
    public class HttpRequest {
    	
    	private String uri;
    
    	public String getUri() {
    		return uri;
    	}
    
    	public void setUri(String uri) {
    		this.uri = uri;
    	}
    	
    	
    	public HttpRequest(InputStream in)  throws IOException{
    		resolverRequest(in);
    	}
    
    	private void resolverRequest(InputStream in) throws IOException {
    		
    		//1.读取 客户端请求过来的数据，解析出来uri
    		byte[] buff = new byte[1024];
    		int len = in.read(buff);
    		
    		if( len>0 ){
    			String msg = new String(buff,0,len);
    			
    			System.out.println("客户端请求信息");
    			
    			System.out.println("客户端请求过来的数据是:" + msg );
    			
    			this.uri = msg.substring( 4,msg.indexOf("HTTP/1.1")  );
    			
    			
    			
    		}else{
    			
    			System.out.println("bad request!");
    			
    		}
    		
    	}
    	
    	
    	public static void main(String[] args) {
    		
    	}
    	
    	
    	
    }

HttpResponse.java代码

package com.zwz;
    
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.text.SimpleDateFormat;
    import java.util.Date;
    
    
    public class HttpResponse {
    
    	private OutputStream out = null;
    
    	private static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    	
    	
    	public HttpResponse(OutputStream out) {
    		super();
    		this.out = out;
    	}
    	
    	
    	//这个方法的作用是把请求的地址传递进来，服务器这个时候向客户端回写响应的文件数据等
    	public void writeFile( String path ) throws IOException{
    		
        		
    			String basepath = new File("").getCanonicalPath();
    			
    			FileInputStream fis = new FileInputStream( basepath +"/"+ path);
    			byte[] buff = new byte[1024];
    			int len = 0;
    			StringBuffer sb = new StringBuffer();
    			//拼凑响应头信息
    			sb.append("HTTP/1.1 200 OK\n");
    			//sb.append("Content-Type: text/html;charset=UTF-8\n");
    			sb.append("\r\n");
    			
    			
    			//响应业务,
    			out.write(sb.toString().getBytes());
            
    			while((len=fis.read(buff))!=-1){
    				out.write(buff,0,len);
    			}
    	
    		fis.close();		
            out.flush();
            out.close();
        
    	}
    	
    	
    	
    }

代码结束之后开始运行下整个项目工程，首先我们需要拷贝一个前端羡慕到eclipse当中，放置在项目的根目录:

![SouthEast 1][]

这个时候运行 server2.java这个文件

在浏览器地址蓝输入  localhost:8888/test/demo.html,显示页面如下

![SouthEast 2][]

ok，到这里大功告成，已经手写实现了一个简单的tomcat  服务

[SouthEast]: /images/20220601/3ad22f05f9a94e378c57822a6bc58b84.png
[SouthEast 1]: /images/20220601/fca29b8882bd490db25c437a4397c4dd.png
[SouthEast 2]: /images/20220601/6020e80e23ed4bb8adbf1de42b91653c.png