实践编写简易Tomcat

拼搏现实的明天。 2021-11-16 23:01 219阅读 0赞

### 1.设计思路 ###

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2h1YWl4aWFvaGFpXzE_size_16_color_FFFFFF_t_70][]

这是一个只能访问静态资源的简易Tomcat

### 2.代码实现 ###

public class Server {
    	
    	public Server(int port,String address) {
    		this.prot = port;
    		this.address = address;
    	}
    	public Server(int port) {
    		this.prot = port;
    	}
    	public Server(String address) {
    		this.address = address;
    	}
    	public Server() {
    	}
    	//初始目录
    	private final String ROOT = System.getProperty("user.dir")+File.separator+"webapps";
    	//监听地址
    	private  String address ="127.0.0.1";
    	//监听端口
    	private  int prot=8080;
    	
    	public void await() {
    		ServerSocket server = null;
    		ThreadPoolExecutor  pool = new  ThreadPoolExecutor(10, 30, 30, TimeUnit.SECONDS, new LinkedTransferQueue<Runnable>());
    		try {
    			server = new ServerSocket(prot,30,InetAddress.getByName(address));
    			System.out.println("开始监听");
    		} catch (IOException e) {
    			e.printStackTrace();
    			System.err.println("ServerSocket 初始化出错");
    		}
    		while(true) {
    			try {
    				Socket socket = server.accept();
    				RequestHandler handler = new RequestHandler(socket.getInputStream(),socket.getOutputStream(),ROOT);
    				pool.execute(handler);
    			} catch (IOException e) {
    				e.printStackTrace();
    				System.err.println();
    			}
    		}
    	}
    	
    }

public class RequestHandler implements Runnable {
    	public RequestHandler(InputStream in,OutputStream out ,String root) {
    		this.in = in;
    		this.out=out;
    		this.ROOT=root;
    	}
    
    	// 默认访问路径
    	private static String url = "/ROOT/index.html";
    
    	private InputStream in = null;
    	
    	private OutputStream out = null;
    	
    	private String ROOT=null;
    	@Override
    	public void run() {
    		System.out.println("开始处理请求");
    		StringBuffer buffer = new StringBuffer();
    		byte[] b = new byte[2048];
    		int i;
    		try {
    			i = in.read(b);
    			for (byte c : b) {
    				buffer.append((char)c);
    			}
    			String temp = buffer.toString();
    			//正则匹配url
    			Pattern regx =Pattern.compile("\\s/\\S*\\s");
    			Matcher matcher = regx.matcher(temp);
    			if(matcher.find()) {
    				SendResponse send = new SendResponse(out,ROOT+matcher.group().trim());
    				send.send();
    			}else {
    				SendResponse send = new SendResponse(out,ROOT+url);
    				send.send();
    			}
    		} catch (IOException e) {
    			System.err.println("读取失败");
    			e.printStackTrace();
    		}finally {
    			try {
    				in.close();
    				out.close();
    			} catch (IOException e) {
    				e.printStackTrace();
    			}
    		}
    	}
    }

public class SendResponse {
    	private String url;
    	private OutputStream out;
    
    	public SendResponse(OutputStream out, String url) {
    		this.out = out;
    		this.url = url;
    	}
    	public void send() throws IOException {
    		File file = new File(url);
    		// 判断请求文件是否存在，如果存在返回
    		if (file.exists()) {
    			FileInputStream in = new FileInputStream(file);
    			byte[] temp = new byte[2048];
    			int endflag = in.read(temp);
    			while (endflag != -1) {
    				out.write(temp);
    				endflag = in.read(temp);
    			}
    			in.close();
    			// 如果不存在报404
    		} else {
    			out.write("404 file not found".getBytes("utf8"));
    			System.out.println("响应成功");
    		}
    	}
    }

public class Main {
    	public static void main(String[] args) {
    		Server server = new Server();
    		server.await();
    	}
    }

### 3.代码说明 ###

开启服务端，默认监听8080端口，设置程序路径，循环监听用户请求，当用户发来请求，采用线程池中的线程去处理用户请求，通过正则匹配用户的访问目录 。

没有匹配到访问默认路径。将用户访问的文件读取出来，响应到浏览器 上。

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2h1YWl4aWFvaGFpXzE_size_16_color_FFFFFF_t_70]: /images/20211116/e17942d95a924a60b0a04d85fbb8776f.png