Tomcat的学习之路一

• 学tomcat之前，先看个简单的例子

 

• 这个是启动类

package tomcatDemo;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;

public class Server {
    
    public static final String SHUT_DOWN="/SHUTDOWN";
    
    private boolean shutdown=false;
    
    public static void main(String[] args) {
        Server server=new Server();
        server.await();
        
    }

    private void await() {

        System.out.println(Thread.currentThread().getName()+" is start");
        
        // TODO Auto-generated method stub
        ServerSocket server = null;
        try {
            server = new ServerSocket(8080, 1, InetAddress.getByName("127.0.0.1"));
        } catch (UnknownHostException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        int i=0;
        while(!shutdown){
            System.out.println("the thread is running "+ i++);
            
            Socket socket=null;
            OutputStream out;
            InputStream in;
            try {
                socket=server.accept();
                
                out = socket.getOutputStream();
                
                in = socket.getInputStream();
                
                Request request = new Request(in);
                
                request.parseUri();
                
                Response response = new Response(out);
                
                response.setRequest(request);
                
                System.out.println(request.getUri());
                if(request.getUri()!=null){
                    if(request.getUri().startsWith("/servlet/")){
                        ServerProcessor processor=new ServerProcessor();
                        processor.process(request,response);
                        
                    }else{
                        StaticProcessor processor=new StaticProcessor();
                        processor.process(request,response);
                    }
                }
                        
                socket.close();
                
                shutdown=SHUT_DOWN.equals(request.getUri());
                
                System.out.println(shutdown);
                
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                System.exit(1);
            }
        }
    }
}

 

• 这个是执行动态请求的类，比如servlet

package tomcatDemo;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.net.URLStreamHandler;

import javax.servlet.Servlet;


public class ServerProcessor {

    public void process(Request request, Response response) {
        // TODO Auto-generated method stub
        String uri = request.getUri();
        String servletName= uri.substring(uri.lastIndexOf("/")+1);
        
        URLClassLoader loader = null;
        
        try {
        URL[] urls =new URL[1];
        
        URLStreamHandler streamHandler=null;
        
        File classPath =new File(Constants.WEB_ROOT);
        
        String repository = (new URL("file",null,classPath.getCanonicalPath()+File.separator)).toString();
        
        urls[0] = new URL(null, repository, streamHandler);
        
        loader=new URLClassLoader(urls);
        
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        
        Class myClass=null;
        
        try {
            myClass = loader.loadClass(servletName);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Servlet servlet=null;
        
        try {
            servlet = (Servlet) myClass.newInstance();
            servlet.service(request, response);;
            
            
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        
    }
    
    

}

• 下面分别是是request和response

package tomcatDemo;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.Enumeration;
import java.util.Locale;
import java.util.Map;

import javax.servlet.AsyncContext;
import javax.servlet.DispatcherType;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class Request implements ServletRequest {
    
    InputStream in;
    
    String uri;

    public Request(InputStream in) {
        super();
        this.in = in;
    }
    
    
    public String getUri()  {
        
            return uri;
    }


    public void parseUri() throws IOException {
        StringBuffer sb = new StringBuffer();
        
        byte[] request=new byte[2014];
        
        in.read(request);
        
        for (int i = 0; i < request.length; i++) {
            sb.append((char)request[i]);
        }
        int start = sb.indexOf(" ");
        
        if(start!=-1){
            int end = sb.indexOf(" ", start+1);
            if(end > start){
                uri=sb.substring(start+1,end);
            }
        }
        System.out.println(uri);
    }


    @Override
    public AsyncContext getAsyncContext() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public Object getAttribute(String arg0) {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public Enumeration<String> getAttributeNames() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public String getCharacterEncoding() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public int getContentLength() {
        // TODO Auto-generated method stub
        return 0;
    }


    @Override
    public String getContentType() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public DispatcherType getDispatcherType() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public ServletInputStream getInputStream() throws IOException {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public String getLocalAddr() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public String getLocalName() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public int getLocalPort() {
        // TODO Auto-generated method stub
        return 0;
    }


    @Override
    public Locale getLocale() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public Enumeration<Locale> getLocales() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public String getParameter(String arg0) {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public Map<String, String[]> getParameterMap() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public Enumeration<String> getParameterNames() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public String[] getParameterValues(String arg0) {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public String getProtocol() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public BufferedReader getReader() throws IOException {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public String getRealPath(String arg0) {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public String getRemoteAddr() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public String getRemoteHost() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public int getRemotePort() {
        // TODO Auto-generated method stub
        return 0;
    }


    @Override
    public RequestDispatcher getRequestDispatcher(String arg0) {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public String getScheme() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public String getServerName() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public int getServerPort() {
        // TODO Auto-generated method stub
        return 0;
    }


    @Override
    public ServletContext getServletContext() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public boolean isAsyncStarted() {
        // TODO Auto-generated method stub
        return false;
    }


    @Override
    public boolean isAsyncSupported() {
        // TODO Auto-generated method stub
        return false;
    }


    @Override
    public boolean isSecure() {
        // TODO Auto-generated method stub
        return false;
    }


    @Override
    public void removeAttribute(String arg0) {
        // TODO Auto-generated method stub
        
    }


    @Override
    public void setAttribute(String arg0, Object arg1) {
        // TODO Auto-generated method stub
        
    }


    @Override
    public void setCharacterEncoding(String arg0) throws UnsupportedEncodingException {
        // TODO Auto-generated method stub
        
    }


    @Override
    public AsyncContext startAsync() {
        // TODO Auto-generated method stub
        return null;
    }


    @Override
    public AsyncContext startAsync(ServletRequest arg0, ServletResponse arg1) {
        // TODO Auto-generated method stub
        return null;
    }
    
    

}

package tomcatDemo;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Locale;

import javax.servlet.ServletOutputStream;
import javax.servlet.ServletResponse;


public class Response implements ServletResponse {
    
    OutputStream out;
    
    Request request;
    
    PrintWriter writer;
    
    private static final int SIZE = 2048;
    
    
    
    
    public Response(OutputStream out) {
        super();
        this.out = out;
    }


    public OutputStream getOut() {
        return out;
    }

    public void setOut(OutputStream out) {
        this.out = out;
    }

    public Request getRequest() {
        return request;
    }

    public void setRequest(Request request) {
        this.request = request;
    }

    public void senndStaticResouce() throws IOException {
        // TODO Auto-generated method stub
        byte[] buffer=new byte[SIZE];
        FileInputStream fis=null;
        try{
            File file=new File(Constants.WEB_ROOT,request.getUri());
            System.out.println(file.getPath());
            fis=new FileInputStream(file);
            int ch=fis.read(buffer,0,SIZE);
            String header="HTTP/1.1 200 OK \r\n"
                    + "Content-Type:text/html\r\n"
                    + "\r\n";
            StringBuilder sb=new StringBuilder(header);
            if(ch!=-1){
                for (int i = 0; i < ch; i++) {
                    sb.append((char)buffer[i]);
                }
                ch=fis.read(buffer,0,SIZE);
            }
            System.out.println(sb);
            
            out.write(sb.toString().getBytes());
            
        }catch (Exception e) {
            // TODO: handle exception
            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>调毛呀，没看到404吗</h1>";
            out.write(errorMessage.getBytes());
        }finally{
            if(fis!=null){
                fis.close();
            }
        }
        
        
        
        
    }

    @Override
    public void flushBuffer() throws IOException {
        // TODO Auto-generated method stub
        
    }

    @Override
    public int getBufferSize() {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public String getCharacterEncoding() {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public String getContentType() {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public Locale getLocale() {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public PrintWriter getWriter() throws IOException {
        // TODO Auto-generated method stub
        writer=new PrintWriter(out,true);
        return writer;
    }

    @Override
    public boolean isCommitted() {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public void reset() {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void resetBuffer() {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void setBufferSize(int arg0) {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void setCharacterEncoding(String arg0) {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void setContentLength(int arg0) {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void setContentType(String arg0) {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void setLocale(Locale arg0) {
        // TODO Auto-generated method stub
        
    }
    
    
    
    
}

• 还有常量类

package tomcatDemo;

public class Constants {

    public static final String WEB_ROOT = System.getProperty("user.dir");
}

•  这个是UML图