how tomcat works---01

向右看齐 2021-09-28 21:00 283阅读 0赞

Request

Response

HttpServer

--------------------

Request.java

package qhf01.pyrmont;
    
    import java.io.IOException;
    import java.io.InputStream;
    
    public class Request {
    	
    	private InputStream input;
    	private String uri;
    	
    	public Request() {
    		super();
    	}
    	
    	public Request(InputStream input) {
    		this.input = input;
    	}
    	
    	public String getUri() {
    		return uri;
    	}
    
    	public void parse() {
    		
    		StringBuffer request = new StringBuffer(2048);
    		
    		int len;
    		byte[] buffer = new byte[2048];
    		try {
    			len = input.read(buffer);
    		} catch (IOException e) {
    			e.printStackTrace();
    			len = -1;
    		}
    		
    		for (int j = 0; j < len; j++) {
    			request.append((char) buffer[j]);
    		}
    		
    		System.out.println(request.toString());
    		
    		uri = parseUri(request.toString());
    	}
    
    	/**
    	 * 	第一行的第一个空格和第二个空格之间就是uri
    	 * 	比如：GET /index.html HTTP/1.1
    	 **/
    	private String parseUri(String requestString) {
    		int index1, index2;
    		index1 = requestString.indexOf(' ');
    		if(index1 != -1) {
    			index2 = requestString.indexOf(' ', index1 + 1);
    			if(index2 > index1) {
    				return requestString.substring(index1 + 1, index2);
    			}
    		}
    		return null;
    	}
    }

Response.java

package qhf01.pyrmont;
    
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    
    public class Response {
    
    	private static final int BUFFER_SIZE = 1024;
    	Request request;
    	OutputStream output;
    
    	public Response() {
    		super();
    	}
    
    	public Response(OutputStream output) {
    		this.output = output;
    	}
    
    	public void setRequest(Request request) {
    		this.request = request;
    	}
    
    	public void sendStaticResource() throws IOException {
    		byte[] bytes = new byte[BUFFER_SIZE];
    		FileInputStream fis = null;
    
    		try {
    			File file = new File(HttpServer.WEB_ROOT, request.getUri());
    			if (file.exists()) {
    				fis = new FileInputStream(file);
    
    				int ch = fis.read(bytes, 0, BUFFER_SIZE);
    
    				while (ch != -1) {
    					output.write(bytes, 0, ch);
    					ch = fis.read(bytes, 0, BUFFER_SIZE);
    				}
    			} else {
    				// file not found
    				String errorMessage = "HTTP/1.1 404 File Not Found\r\n"
    						+ "Content-Type: text/html\r\n"
    						+ "Content-Length: 23\r\n" 
    						+ "\r\n"
    						+ "<h1>File Not Found</h1>";
    
    				output.write(errorMessage.getBytes());
    			}
    
    		} catch (Exception e) {
    			System.out.println(e.toString());
    		} finally {
    			if (fis != null) {
    				fis.close();
    			}
    		}
    	}
    	public static void main(String[] args) {
    		System.out.println(System.getProperty("user.dir") + File.separator + "webroot");
    	}
    
    }

HttpServer.java

package qhf01.pyrmont;
    
    import java.io.File;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    import java.net.InetAddress;
    import java.net.ServerSocket;
    import java.net.Socket;
    
    public class HttpServer {
    	public static final String WEB_ROOT = System.getProperty("user.dir") + File.separator + "webroot";
    	
    	private static final String SHUTDOWN_COMMAND = "/SHUTDOWN";
    	
    	private boolean shutdown = false;
    	
    	public static void main(String[] args) {
    		HttpServer server = new HttpServer();
    		server.await();
    	}
    
    	private void await() {
    		ServerSocket serverSocket = null;
    		int port = 8080;
    		try {
    			serverSocket = new ServerSocket(port, 1, InetAddress.getByName("127.0.0.1"));
    		} catch (IOException e) {
    			e.printStackTrace();
    			System.exit(1);
    		}
    		
    		while (!shutdown) {
    			Socket socket = null;
    			InputStream input = null;
    			OutputStream output = null;
    			
    			try {
    				//1.服务器开机，等待连接，直到连接了执行这下面23后关socket，下次循环再连接
    				socket = serverSocket.accept();
    				
    				input = socket.getInputStream();
    				output = socket.getOutputStream();
    				
    				//2.解析请求
    				Request request = new Request(input);
    				request.parse();
    				
    				//3.回应设置对应的请求，发送静态源
    				Response response = new Response(output);
    				response.setRequest(request);
    				response.sendStaticResource();
    				
    				//4.关socket
    				socket.close();
    				
    				//5.检查请求中的uri 中是否是shutdown 命令，如是则shutdown 为true 会退出循环
    				shutdown = request.getUri().equals(SHUTDOWN_COMMAND);
    				
    			} catch (Exception e) {
    				e.printStackTrace();
    				continue;//错误继续循环
    			}
    		}
    	}
    }