package day0522;import java.net.Socket;
import java.net.ServerSocket;
import java.net.InetAddress;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;public class HttpServer1 {/** WEB_ROOT is the directory where our HTML and other files reside.*  For this package, WEB_ROOT is the "webroot" directory under the working*  directory.*  The working directory is the location in the file system*  from where the java command was invoked.*/// shutdown commandprivate static final String SHUTDOWN_COMMAND = "/SHUTDOWN";// the shutdown command receivedprivate boolean shutdown = false;public static void main(String[] args) {HttpServer1 server = new HttpServer1();server.await();}public 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);}// Loop waiting for a requestwhile (!shutdown) {Socket socket = null;InputStream input = null;OutputStream output = null;try {socket = serverSocket.accept();input = socket.getInputStream();output = socket.getOutputStream();// create Request object and parseRequest request = new Request(input);request.parse();// create Response objectResponse response = new Response(output);response.setRequest(request);// check if this is a request for a servlet or a static resource// a request for a servlet begins with "/servlet/"if (request.getUri().startsWith("/servlet/")) {ServletProcessor1 processor = new ServletProcessor1();processor.process(request, response);}else {StaticResourceProcessor processor = new StaticResourceProcessor();processor.process(request, response);}// Close the socketsocket.close();//check if the previous URI is a shutdown commandshutdown = request.getUri().equals(SHUTDOWN_COMMAND);}catch (Exception e) {e.printStackTrace();System.exit(1);}}}
}

package day0522;import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.UnsupportedEncodingException;
import java.util.Enumeration;
import java.util.Locale;
import java.util.Map;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletRequest;public class Request implements ServletRequest {private InputStream input;private String uri;public Request(InputStream input) {this.input = input;}public String getUri() {return uri;}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;}public void parse() {// Read a set of characters from the socketStringBuffer request = new StringBuffer(2048);int i;byte[] buffer = new byte[2048];try {i = input.read(buffer);}catch (IOException e) {e.printStackTrace();i = -1;}for (int j=0; j<i; j++) {request.append((char) buffer[j]);}System.out.print(request.toString());uri = parseUri(request.toString());}/* implementation of the ServletRequest*/public Object getAttribute(String attribute) {return null;}public Enumeration getAttributeNames() {return null;}public String getRealPath(String path) {return null;}public RequestDispatcher getRequestDispatcher(String path) {return null;}public boolean isSecure() {return false;}public String getCharacterEncoding() {return null;}public int getContentLength() {return 0;}public String getContentType() {return null;}public ServletInputStream getInputStream() throws IOException {return null;}public Locale getLocale() {return null;}public Enumeration getLocales() {return null;}public String getParameter(String name) {return null;}public Map getParameterMap() {return null;}public Enumeration getParameterNames() {return null;}public String[] getParameterValues(String parameter) {return null;}public String getProtocol() {return null;}public BufferedReader getReader() throws IOException {return null;}public String getRemoteAddr() {return null;}public String getRemoteHost() {return null;}public String getScheme() {return null;}public String getServerName() {return null;}public int getServerPort() {return 0;}public void removeAttribute(String attribute) {}public void setAttribute(String key, Object value) {}public void setCharacterEncoding(String encoding)throws UnsupportedEncodingException {}@Override
public int getRemotePort() {// TODO Auto-generated method stubreturn 0;
}@Override
public String getLocalName() {// TODO Auto-generated method stubreturn null;
}@Override
public String getLocalAddr() {// TODO Auto-generated method stubreturn null;
}@Override
public int getLocalPort() {// TODO Auto-generated method stubreturn 0;
}}

package day0522;import java.io.OutputStream;
import java.io.IOException;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.File;
import java.io.PrintWriter;
import java.util.Locale;
import javax.servlet.ServletResponse;
import javax.servlet.ServletOutputStream;public class Response implements ServletResponse {private static final int BUFFER_SIZE = 1024;Request request;OutputStream output;PrintWriter writer;public Response(OutputStream output) {this.output = output;}public void setRequest(Request request) {this.request = request;}/* This method is used to serve a static page */public void sendStaticResource() throws IOException {byte[] bytes = new byte[BUFFER_SIZE];FileInputStream fis = null;try {/* request.getUri has been replaced by request.getRequestURI */File file = new File(Constants.WEB_ROOT, request.getUri());fis = new FileInputStream(file);/*HTTP Response = Status-Line*(( general-header | response-header | entity-header ) CRLF)CRLF[ message-body ]Status-Line = HTTP-Version SP Status-Code SP Reason-Phrase CRLF*/int ch = fis.read(bytes, 0, BUFFER_SIZE);while (ch!=-1) {output.write(bytes, 0, ch);ch = fis.read(bytes, 0, BUFFER_SIZE);}}catch (FileNotFoundException e) {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());}finally {if (fis!=null)fis.close();}}/** implementation of ServletResponse  */public void flushBuffer() throws IOException {}public int getBufferSize() {return 0;}public String getCharacterEncoding() {return null;}public Locale getLocale() {return null;}public ServletOutputStream getOutputStream() throws IOException {return null;}public PrintWriter getWriter() throws IOException {// autoflush is true, println() will flush,// but print() will not.writer = new PrintWriter(output, true);return writer;}public boolean isCommitted() {return false;}public void reset() {}public void resetBuffer() {}public void setBufferSize(int size) {}public void setContentLength(int length) {}public void setContentType(String type) {}public void setLocale(Locale locale) {}@Override
public String getContentType() {// TODO Auto-generated method stubreturn null;
}@Override
public void setCharacterEncoding(String charset) {// TODO Auto-generated method stub}
}

package day0522;import java.io.IOException;public class StaticResourceProcessor {public void process(Request request, Response response) {try {response.sendStaticResource();}catch (IOException e) {e.printStackTrace();}}
}

package day0522;import java.net.URL;
import java.net.URLClassLoader;
import java.net.URLStreamHandler;
import java.io.File;
import java.io.IOException;
import javax.servlet.Servlet;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;public class ServletProcessor1 {public void process(Request request, Response response) {String uri = request.getUri();String servletName = uri.substring(uri.lastIndexOf("/") + 1);URLClassLoader loader = null;try {// create a URLClassLoaderURL[] urls = new URL[1];URLStreamHandler streamHandler = null;File classPath = new File(Constants.WEB_ROOT);// the forming of repository is taken from the createClassLoader method in// org.apache.catalina.startup.ClassLoaderFactoryString repository = (new URL("file", null, classPath.getCanonicalPath() + File.separator)).toString() ;// the code for forming the URL is taken from the addRepository method in// org.apache.catalina.loader.StandardClassLoader class.urls[0] = new URL(null, repository, streamHandler);loader = new URLClassLoader(urls);}catch (IOException e) {System.out.println(e.toString() );}Class myClass = null;try {myClass = loader.loadClass(servletName);}catch (ClassNotFoundException e) {System.out.println(e.toString());}Servlet servlet = null;try {servlet = (Servlet) myClass.newInstance();servlet.service((ServletRequest) request, (ServletResponse) response);}catch (Exception e) {System.out.println(e.toString());}catch (Throwable e) {System.out.println(e.toString());}}
}