tomcat之连接器

深入学习Java Web服务器系列三

一个简单的连接器

下面我们来学习tomcat中的连接器。
首先我们先了解一下Catalina的结构图。

1. Catalina架构图

catalina 就是Tomcat服务器使用Servlet容器的名字。
Tomcat的核心可以分为3个部分:

Web容器—处理静态页面；
catalina —处理servlet;
JSP容器 — jsp页面翻译成一般的servlet

我们可以把catalina看成是两个主要模块组成的，连接器（connector）和容器（container）。

连接器是用来“连接”容器里边的请求的。它的工作是为接收到每一个HTTP请求构造一个request和response对象。然后它把流程传递给容器。容器从连接器接收到requset和response对象之后调用servlet的service方法用于响应。

在本系列的前一篇博文中，一个简单的servlet容器，我们把创建request和response对象的功能直接交给了我们的容器使用，而本篇博文，我们将写一个可以创建更好的请求和响应对象的连接器，用来改善之前的程序。

2. StringManager类(Tomcat5)

在Tomcat中，错误信息对于系统管理员和servlet程序员都是有用的。例如，Tomcat记录错误信息，让系统管理员可以定位发生的任何异常。对servlet程序员来说，Tomcat会在抛出的任何一个 javax.servlet.ServletException中发送一个错误信息，这样程序员可以知道他/她的servlet究竟发送什么错误了。

Tomcat所采用的方法是在一个属性文件里边存储错误信息，这样，可以容易的修改这些信息。不过，Tomcat中有数以百计的类。把所有类使用的错误信息存储到一个大的属性文件里边将会容易产生维护的噩梦。为了避免这一情况，Tomcat为每个包都分配一个属性文件。例如，在包 org.apache.catalina.connector里边的属性文件包含了该包所有的类抛出的所有错误信息。每个属性文件都会被一个 org.apache.catalina.util.StringManager类的实例所处理。当Tomcat运行时，将会有许多 StringManager实例，每个实例会读取包对应的一个属性文件。此外，由于Tomcat的受欢迎程度，提供多种语言的错误信息也是有意义的。

当包里边的一个类需要查找放在该包属性文件的一个错误信息时，它首先会获得一个StringManager实例。不过，相同包里边的许多类可能也需要 StringManager，为每个对象创建一个StringManager实例是一种资源浪费。因此，StringManager类被设计成一个StringManager实例可以被包里边的所有类共享，这里，StringManager被设计成了单例模式的。我们通过传递一个包名来调用它的公共静态方法 getManager来获得一个实例。每个实例存储在一个以包名为键(key)的Hashtable中。

private static Hashtable managers = new Hashtable();
public synchronized static StringManager getManager(String packageName)
{StringManager mgr = (StringManager)managers.get(packageName);if (mgr == null){mgr = new StringManager(packageName);managers.put(packageName, mgr);}return mgr;
}

我们将在这篇博文中的程序中使用这种思想。

3. 模块划分

下面我们自己仿照tomcat来实现一个自己的连接器，我们将把本篇博文中的程序分成三个模块，connector, startup和core。

startup模块只有一个类，Bootstrap，用来启动应用的。

connector模块的类可以分为五组：
- 连接器和它的支撑类(HttpConnector和HttpProcessor)
- 指代HTTP请求的类(HttpRequest)和它的辅助类
- 指代HTTP响应的类(HttpResponse)和它的辅助类。
- Facade类(HttpRequestFacade和HttpResponseFacade)
- Constant类

core模块由两个类组成：ServletProcessor和StaticResourceProcessor。

程序的uml图如下图所示：

3.1 startup模块

startup模块中只有一个启动类。

Bootstrap类
Bootstrap类中的main方法实例化HttpConnector类并调用它的start方法

import ex03.pyrmont.connector.http.HttpConnector;public final class Bootstrap {public static void main(String[] args) {HttpConnector connector = new HttpConnector();connector.start();}
}

HttpConnector类的定义见下面模块。

3.2 connector模块

HttpConnector类

HttpConnector类指代一个连接器，职责是创建一个服务器套接字用来等待前来的HTTP请求。
HttpConnector类实现了java.lang.Runnable，所以它能被它自己的线程专用。当你启动应用程序，一个HttpConnector的实例被创建，并且它的run方法被执行。
一个HttpConnector主要完成下面的事情：

等待HTTP请求
为每个请求创建个HttpProcessor实例
调用HttpProcessor的process方法

import java.io.IOException;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;public class HttpConnector implements Runnable {boolean stopped;private String scheme = "http";public String getScheme() {return scheme;}public void run() {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 (!stopped) {// Accept the next incoming connection from the server socketSocket socket = null;try {socket = serverSocket.accept();}catch (Exception e) {continue;}// Hand this socket off to an HttpProcessorHttpProcessor processor = new HttpProcessor(this);processor.process(socket);}}public void start() {Thread thread = new Thread(this);thread.start();}
}

HttpProcessor类
HttpProcessor类的process方法接受前来的HTTP请求的套接字，会做下面的事情

创建一个HttpRequest对象
创建一个HttpResponse对象
解析HTTP请求的第一行和头部，并放到HttpRequest对象
解析HttpRequest和HttpResponse对象到一个ServletProcessor或者
StaticResourceProcessor

import ex03.pyrmont.ServletProcessor;
import ex03.pyrmont.StaticResourceProcessor;import java.net.Socket;
import java.io.OutputStream;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;import org.apache.catalina.util.RequestUtil;
import org.apache.catalina.util.StringManager;/* this class used to be called HttpServer */
public class HttpProcessor {public HttpProcessor(HttpConnector connector) {this.connector = connector;}/*** The HttpConnector with which this processor is associated.*/private HttpConnector connector = null;private HttpRequest request;private HttpRequestLine requestLine = new HttpRequestLine();private HttpResponse response;protected String method = null;protected String queryString = null;/*** The string manager for this package.*/protected StringManager sm =StringManager.getManager("ex03.pyrmont.connector.http");public void process(Socket socket) {SocketInputStream input = null;OutputStream output = null;try {input = new SocketInputStream(socket.getInputStream(), 2048);output = socket.getOutputStream();// create HttpRequest object and parserequest = new HttpRequest(input);// create HttpResponse objectresponse = new HttpResponse(output);response.setRequest(request);response.setHeader("Server", "Pyrmont Servlet Container");parseRequest(input, output);parseHeaders(input);//check if this is a request for a servlet or a static resource//a request for a servlet begins with "/servlet/"if (request.getRequestURI().startsWith("/servlet/")) {ServletProcessor processor = new ServletProcessor();processor.process(request, response);}else {StaticResourceProcessor processor = new StaticResourceProcessor();processor.process(request, response);}// Close the socketsocket.close();// no shutdown for this application}catch (Exception e) {e.printStackTrace();}}/*** This method is the simplified version of the similar method in* org.apache.catalina.connector.http.HttpProcessor.* However, this method only parses some "easy" headers, such as* "cookie", "content-length", and "content-type", and ignore other headers.* @param input The input stream connected to our socket** @exception IOException if an input/output error occurs* @exception ServletException if a parsing error occurs*/private void parseHeaders(SocketInputStream input)throws IOException, ServletException {while (true) {HttpHeader header = new HttpHeader();;// Read the next headerinput.readHeader(header);if (header.nameEnd == 0) {if (header.valueEnd == 0) {return;}else {throw new ServletException(sm.getString("httpProcessor.parseHeaders.colon"));}}String name = new String(header.name, 0, header.nameEnd);String value = new String(header.value, 0, header.valueEnd);request.addHeader(name, value);// do something for some headers, ignore others.if (name.equals("cookie")) {Cookie cookies[] = RequestUtil.parseCookieHeader(value);for (int i = 0; i < cookies.length; i++) {if (cookies[i].getName().equals("jsessionid")) {// Override anything requested in the URLif (!request.isRequestedSessionIdFromCookie()) {// Accept only the first session id cookierequest.setRequestedSessionId(cookies[i].getValue());request.setRequestedSessionCookie(true);request.setRequestedSessionURL(false);}}request.addCookie(cookies[i]);}}else if (name.equals("content-length")) {int n = -1;try {n = Integer.parseInt(value);}catch (Exception e) {throw new ServletException(sm.getString("httpProcessor.parseHeaders.contentLength"));}request.setContentLength(n);}else if (name.equals("content-type")) {request.setContentType(value);}} //end while}private void parseRequest(SocketInputStream input, OutputStream output)throws IOException, ServletException {// Parse the incoming request lineinput.readRequestLine(requestLine);String method =new String(requestLine.method, 0, requestLine.methodEnd);String uri = null;String protocol = new String(requestLine.protocol, 0, requestLine.protocolEnd);// Validate the incoming request lineif (method.length() < 1) {throw new ServletException("Missing HTTP request method");}else if (requestLine.uriEnd < 1) {throw new ServletException("Missing HTTP request URI");}// Parse any query parameters out of the request URIint question = requestLine.indexOf("?");if (question >= 0) {request.setQueryString(new String(requestLine.uri, question + 1,requestLine.uriEnd - question - 1));uri = new String(requestLine.uri, 0, question);}else {request.setQueryString(null);uri = new String(requestLine.uri, 0, requestLine.uriEnd);}// Checking for an absolute URI (with the HTTP protocol)if (!uri.startsWith("/")) {int pos = uri.indexOf("://");// Parsing out protocol and host nameif (pos != -1) {pos = uri.indexOf('/', pos + 3);if (pos == -1) {uri = "";}else {uri = uri.substring(pos);}}}// Parse any requested session ID out of the request URIString match = ";jsessionid=";int semicolon = uri.indexOf(match);if (semicolon >= 0) {String rest = uri.substring(semicolon + match.length());int semicolon2 = rest.indexOf(';');if (semicolon2 >= 0) {request.setRequestedSessionId(rest.substring(0, semicolon2));rest = rest.substring(semicolon2);}else {request.setRequestedSessionId(rest);rest = "";}request.setRequestedSessionURL(true);uri = uri.substring(0, semicolon) + rest;}else {request.setRequestedSessionId(null);request.setRequestedSessionURL(false);}// Normalize URI (using String operations at the moment)String normalizedUri = normalize(uri);// Set the corresponding request properties((HttpRequest) request).setMethod(method);request.setProtocol(protocol);if (normalizedUri != null) {((HttpRequest) request).setRequestURI(normalizedUri);}else {((HttpRequest) request).setRequestURI(uri);}if (normalizedUri == null) {throw new ServletException("Invalid URI: " + uri + "'");}}/*** Return a context-relative path, beginning with a "/", that represents* the canonical version of the specified path after ".." and "." elements* are resolved out.  If the specified path attempts to go outside the* boundaries of the current context (i.e. too many ".." path elements* are present), return <code>null</code> instead.** @param path Path to be normalized*/protected String normalize(String path) {if (path == null)return null;// Create a place for the normalized pathString normalized = path;// Normalize "/%7E" and "/%7e" at the beginning to "/~"if (normalized.startsWith("/%7E") || normalized.startsWith("/%7e"))normalized = "/~" + normalized.substring(4);// Prevent encoding '%', '/', '.' and '\', which are special reserved// charactersif ((normalized.indexOf("%25") >= 0)|| (normalized.indexOf("%2F") >= 0)|| (normalized.indexOf("%2E") >= 0)|| (normalized.indexOf("%5C") >= 0)|| (normalized.indexOf("%2f") >= 0)|| (normalized.indexOf("%2e") >= 0)|| (normalized.indexOf("%5c") >= 0)) {return null;}if (normalized.equals("/."))return "/";// Normalize the slashes and add leading slash if necessaryif (normalized.indexOf('\\') >= 0)normalized = normalized.replace('\\', '/');if (!normalized.startsWith("/"))normalized = "/" + normalized;// Resolve occurrences of "//" in the normalized pathwhile (true) {int index = normalized.indexOf("//");if (index < 0)break;normalized = normalized.substring(0, index) +normalized.substring(index + 1);}// Resolve occurrences of "/./" in the normalized pathwhile (true) {int index = normalized.indexOf("/./");if (index < 0)break;normalized = normalized.substring(0, index) +normalized.substring(index + 2);}// Resolve occurrences of "/../" in the normalized pathwhile (true) {int index = normalized.indexOf("/../");if (index < 0)break;if (index == 0)return (null);  // Trying to go outside our contextint index2 = normalized.lastIndexOf('/', index - 1);normalized = normalized.substring(0, index2) +normalized.substring(index + 3);}// Declare occurrences of "/..." (three or more dots) to be invalid// (on some Windows platforms this walks the directory tree!!!)if (normalized.indexOf("/...") >= 0)return (null);// Return the normalized path that we have completedreturn (normalized);}}

SocketInputStream 是org.apache.catalina.connector.http.SocketInputStream。该类提供了获取请求行（request line）和请求头（request header）的方法。通过传入一个 InputStream 对象和一个代表缓冲区大小的整数值来创建
SocketInputStream 对象。

HttpProcessor 的 process 调用其私有方法 parseRequest 来解析请求行（request line，即 http 请求的第一行）。下面是一个请求行（request line）的例子：

GET /myApp/ModernServlet?userName=tarzan&password=pwd HTTP/1.1

注意：“GET”后面和“HTTP”前面各有一个空格。
请求行的第 2 部分是 uri 加上查询字符串。在上面的例子中，uri 是：
/myApp/ModernServlet
问号后面的都是查询字符串，这里是：
userName=tarzan&password=pwd
在 servlet/jsp 编程中，参数 jsessionid 通常是嵌入到 cookie 中的，也可以将其嵌入到查询字符串中。

请求头（request header）由 HttpHeader 对象表示。可以通过 HttpHeader 的无参构造方法建立对象，并将其作为参数传给 SocketInputStream 的 readHeader 方法，该方法会自动填充 HttpHeader 对象。parseHeader
方法内有一个循环体，不断的从 SocketInputStream 中读取 header 信息，直到读完。获取 header 的 name 和value 值可使用下米娜的语句：
String name = new String(header.name, 0, header.nameEnd);
String value = new String(header.value, 0, header.valueEnd);
获取到 header 的 name 和 value 后，要将其填充到 HttpRequest 的 header 属性（hashMap 类型）中：
request.addHeader(name, value);
其中某些 header 要设置到 request 对象的属性中，如 contentLength 等。

cookie 是由浏览器作为请求头的一部分发送的，这样的请求头的名字是 cookie，它的值是一个 keyvalue
对。举例如下：
Cookie: userName=budi; password=pwd;
对 cookie 的解析是通过 org.apache.catalina.util.RequestUtil 类的 parseCookieHeader 方法完成的。该方法接受一个 cookie 头字符串，返回一个 javax.servlet.http.Cookie 类型的数组。

我们通过解析http请求的信息并存在httprequest和httpresponse中，并通过process方法传递到core模块。

创建一个HttpRequest对象
HttpRequest类在上面两节的内容上增加了三个变量和其一些方法：

protected HashMap headers = new HashMap();
protected ArrayList cookies = new ArrayList();
protected ParameterMap parameters = null;

这三个变量存放着Http请求的头部，cookies和参数。

因此，一个servlet程序员可以从javax.servlet.http.HttpServletRequest中的下列方法中取得正确的返回值：
getCookies,getDateHeader,getHeader, getHeaderNames, getHeaders, getParameter, getPrameterMap,getParameterNames和getParameterValues。

HttpRequest

import ex03.pyrmont.connector.RequestStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import javax.servlet.http.Cookie;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletInputStream;
import java.security.Principal;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.UnsupportedEncodingException;
import java.net.InetAddress;
import java.net.Socket;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import org.apache.catalina.util.Enumerator;
import org.apache.catalina.util.ParameterMap;
import org.apache.catalina.util.RequestUtil;public class HttpRequest implements HttpServletRequest {private String contentType;private int contentLength;private InetAddress inetAddress;private InputStream input;private String method;private String protocol;private String queryString;private String requestURI;private String serverName;private int serverPort;private Socket socket;private boolean requestedSessionCookie;private String requestedSessionId;private boolean requestedSessionURL;/*** The request attributes for this request.*/protected HashMap attributes = new HashMap();/*** The authorization credentials sent with this Request.*/protected String authorization = null;/*** The context path for this request.*/protected String contextPath = "";/*** The set of cookies associated with this Request.*/protected ArrayList cookies = new ArrayList();/*** An empty collection to use for returning empty Enumerations.  Do not* add any elements to this collection!*/protected static ArrayList empty = new ArrayList();/*** The set of SimpleDateFormat formats to use in getDateHeader().*/protected SimpleDateFormat formats[] = {new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US),new SimpleDateFormat("EEEEEE, dd-MMM-yy HH:mm:ss zzz", Locale.US),new SimpleDateFormat("EEE MMMM d HH:mm:ss yyyy", Locale.US)};/*** The HTTP headers associated with this Request, keyed by name.  The* values are ArrayLists of the corresponding header values.*/protected HashMap headers = new HashMap();/*** The parsed parameters for this request.  This is populated only if* parameter information is requested via one of the* <code>getParameter()</code> family of method calls.  The key is the* parameter name, while the value is a String array of values for this* parameter.* <p>* <strong>IMPLEMENTATION NOTE</strong> - Once the parameters for a* particular request are parsed and stored here, they are not modified.* Therefore, application level access to the parameters need not be* synchronized.*/protected ParameterMap parameters = null;/*** Have the parameters for this request been parsed yet?*/protected boolean parsed = false;protected String pathInfo = null;/*** The reader that has been returned by <code>getReader</code>, if any.*/protected BufferedReader reader = null;/*** The ServletInputStream that has been returned by* <code>getInputStream()</code>, if any.*/protected ServletInputStream stream = null;public HttpRequest(InputStream input) {this.input = input;}public void addHeader(String name, String value) {name = name.toLowerCase();synchronized (headers) {ArrayList values = (ArrayList) headers.get(name);if (values == null) {values = new ArrayList();headers.put(name, values);}values.add(value);}}/*** Parse the parameters of this request, if it has not already occurred.* If parameters are present in both the query string and the request* content, they are merged.*/protected void parseParameters() {if (parsed)return;ParameterMap results = parameters;if (results == null)results = new ParameterMap();results.setLocked(false);String encoding = getCharacterEncoding();if (encoding == null)encoding = "ISO-8859-1";// Parse any parameters specified in the query stringString queryString = getQueryString();try {RequestUtil.parseParameters(results, queryString, encoding);}catch (UnsupportedEncodingException e) {;}// Parse any parameters specified in the input streamString contentType = getContentType();if (contentType == null)contentType = "";int semicolon = contentType.indexOf(';');if (semicolon >= 0) {contentType = contentType.substring(0, semicolon).trim();}else {contentType = contentType.trim();}if ("POST".equals(getMethod()) && (getContentLength() > 0)&& "application/x-www-form-urlencoded".equals(contentType)) {try {int max = getContentLength();int len = 0;byte buf[] = new byte[getContentLength()];ServletInputStream is = getInputStream();while (len < max) {int next = is.read(buf, len, max - len);if (next < 0 ) {break;}len += next;}is.close();if (len < max) {throw new RuntimeException("Content length mismatch");}RequestUtil.parseParameters(results, buf, encoding);}catch (UnsupportedEncodingException ue) {;}catch (IOException e) {throw new RuntimeException("Content read fail");}}// Store the final resultsresults.setLocked(true);parsed = true;parameters = results;}public void addCookie(Cookie cookie) {synchronized (cookies) {cookies.add(cookie);}}/*** Create and return a ServletInputStream to read the content* associated with this Request.  The default implementation creates an* instance of RequestStream associated with this request, but this can* be overridden if necessary.** @exception IOException if an input/output error occurs*/public ServletInputStream createInputStream() throws IOException {return (new RequestStream(this));}public InputStream getStream() {return input;}public void setContentLength(int length) {this.contentLength = length;}public void setContentType(String type) {this.contentType = type;}public void setInet(InetAddress inetAddress) {this.inetAddress = inetAddress;}public void setContextPath(String path) {if (path == null)this.contextPath = "";elsethis.contextPath = path;}public void setMethod(String method) {this.method = method;}public void setPathInfo(String path) {this.pathInfo = path;}public void setProtocol(String protocol) {this.protocol = protocol;}public void setQueryString(String queryString) {this.queryString = queryString;}public void setRequestURI(String requestURI) {this.requestURI = requestURI;}/*** Set the name of the server (virtual host) to process this request.** @param name The server name*/public void setServerName(String name) {this.serverName = name;}/*** Set the port number of the server to process this request.** @param port The server port*/public void setServerPort(int port) {this.serverPort = port;}public void setSocket(Socket socket) {this.socket = socket;}/*** Set a flag indicating whether or not the requested session ID for this* request came in through a cookie.  This is normally called by the* HTTP Connector, when it parses the request headers.** @param flag The new flag*/public void setRequestedSessionCookie(boolean flag) {this.requestedSessionCookie = flag;}public void setRequestedSessionId(String requestedSessionId) {this.requestedSessionId = requestedSessionId;}public void setRequestedSessionURL(boolean flag) {requestedSessionURL = flag;}/* implementation of the HttpServletRequest*/public Object getAttribute(String name) {synchronized (attributes) {return (attributes.get(name));}}public Enumeration getAttributeNames() {synchronized (attributes) {return (new Enumerator(attributes.keySet()));}}public String getAuthType() {return null;}public String getCharacterEncoding() {return null;}public int getContentLength() {return contentLength ;}public String getContentType() {return contentType;}public String getContextPath() {return contextPath;}public Cookie[] getCookies() {synchronized (cookies) {if (cookies.size() < 1)return (null);Cookie results[] = new Cookie[cookies.size()];return ((Cookie[]) cookies.toArray(results));}}public long getDateHeader(String name) {String value = getHeader(name);if (value == null)return (-1L);// Work around a bug in SimpleDateFormat in pre-JDK1.2b4// (Bug Parade bug #4106807)value += " ";// Attempt to convert the date header in a variety of formatsfor (int i = 0; i < formats.length; i++) {try {Date date = formats[i].parse(value);return (date.getTime());}catch (ParseException e) {;}}throw new IllegalArgumentException(value);}public String getHeader(String name) {name = name.toLowerCase();synchronized (headers) {ArrayList values = (ArrayList) headers.get(name);if (values != null)return ((String) values.get(0));elsereturn null;}}public Enumeration getHeaderNames() {synchronized (headers) {return (new Enumerator(headers.keySet()));}}public Enumeration getHeaders(String name) {name = name.toLowerCase();synchronized (headers) {ArrayList values = (ArrayList) headers.get(name);if (values != null)return (new Enumerator(values));elsereturn (new Enumerator(empty));}}public ServletInputStream getInputStream() throws IOException {if (reader != null)throw new IllegalStateException("getInputStream has been called");if (stream == null)stream = createInputStream();return (stream);}public int getIntHeader(String name) {String value = getHeader(name);if (value == null)return (-1);elsereturn (Integer.parseInt(value));}public Locale getLocale() {return null;}public Enumeration getLocales() {return null;}public String getMethod() {return method;}public String getParameter(String name) {parseParameters();String values[] = (String[]) parameters.get(name);if (values != null)return (values[0]);elsereturn (null);}public Map getParameterMap() {parseParameters();return (this.parameters);}public Enumeration getParameterNames() {parseParameters();return (new Enumerator(parameters.keySet()));}public String[] getParameterValues(String name) {parseParameters();String values[] = (String[]) parameters.get(name);if (values != null)return (values);elsereturn null;}public String getPathInfo() {return pathInfo;}public String getPathTranslated() {return null;}public String getProtocol() {return protocol;}public String getQueryString() {return queryString;}public BufferedReader getReader() throws IOException {if (stream != null)throw new IllegalStateException("getInputStream has been called.");if (reader == null) {String encoding = getCharacterEncoding();if (encoding == null)encoding = "ISO-8859-1";InputStreamReader isr =new InputStreamReader(createInputStream(), encoding);reader = new BufferedReader(isr);}return (reader);}public String getRealPath(String path) {return null;}public String getRemoteAddr() {return null;}public String getRemoteHost() {return null;}public String getRemoteUser() {return null;}public RequestDispatcher getRequestDispatcher(String path) {return null;}public String getScheme() {return null;}public String getServerName() {return null;}public int getServerPort() {return 0;}public String getRequestedSessionId() {return null;}public String getRequestURI() {return requestURI;}public StringBuffer getRequestURL() {return null;}public HttpSession getSession() {return null;}public HttpSession getSession(boolean create) {return null;}public String getServletPath() {return null;}public Principal getUserPrincipal() {return null;}public boolean isRequestedSessionIdFromCookie() {return false;}public boolean isRequestedSessionIdFromUrl() {return isRequestedSessionIdFromURL();}public boolean isRequestedSessionIdFromURL() {return false;}public boolean isRequestedSessionIdValid() {return false;}public boolean isSecure() {return false;}public boolean isUserInRole(String role) {return false;}public void removeAttribute(String attribute) {}public void setAttribute(String key, Object value) {}/*** Set the authorization credentials sent with this request.** @param authorization The new authorization credentials*/public void setAuthorization(String authorization) {this.authorization = authorization;}public void setCharacterEncoding(String encoding) throws UnsupportedEncodingException {}
}

HttpResponse类

import ex03.pyrmont.connector.ResponseStream;
import ex03.pyrmont.connector.ResponseWriter;
import ex03.pyrmont.connector.http.Constants;import java.io.OutputStream;
import java.io.IOException;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.File;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.text.SimpleDateFormat;
import java.util.Locale;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletResponse;
import org.apache.catalina.util.CookieTools;public class HttpResponse implements HttpServletResponse {// the default buffer sizeprivate static final int BUFFER_SIZE = 1024;HttpRequest request;OutputStream output;PrintWriter writer;protected byte[] buffer = new byte[BUFFER_SIZE];protected int bufferCount = 0;/*** Has this response been committed yet?*/protected boolean committed = false;/*** The actual number of bytes written to this Response.*/protected int contentCount = 0;/*** The content length associated with this Response.*/protected int contentLength = -1;/*** The content type associated with this Response.*/protected String contentType = null;/*** The character encoding associated with this Response.*/protected String encoding = null;/*** The set of Cookies associated with this Response.*/protected ArrayList cookies = new ArrayList();/*** The HTTP headers explicitly added via addHeader(), but not including* those to be added with setContentLength(), setContentType(), and so on.* This collection is keyed by the header name, and the elements are* ArrayLists containing the associated values that have been set.*/protected HashMap headers = new HashMap();/*** The date format we will use for creating date headers.*/protected final SimpleDateFormat format =new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz",Locale.US);/*** The error message set by <code>sendError()</code>.*/protected String message = getStatusMessage(HttpServletResponse.SC_OK);/*** The HTTP status code associated with this Response.*/protected int status = HttpServletResponse.SC_OK;public HttpResponse(OutputStream output) {this.output = output;}/*** call this method to send headers and response to the output*/public void finishResponse() {// sendHeaders();// Flush and close the appropriate output mechanismif (writer != null) {writer.flush();writer.close();}}public int getContentLength() {return contentLength;}public String getContentType() {return contentType;}protected String getProtocol() {return request.getProtocol();}/*** Returns a default status message for the specified HTTP status code.** @param status The status code for which a message is desired*/protected String getStatusMessage(int status) {switch (status) {case SC_OK:return ("OK");case SC_ACCEPTED:return ("Accepted");case SC_BAD_GATEWAY:return ("Bad Gateway");case SC_BAD_REQUEST:return ("Bad Request");case SC_CONFLICT:return ("Conflict");case SC_CONTINUE:return ("Continue");case SC_CREATED:return ("Created");case SC_EXPECTATION_FAILED:return ("Expectation Failed");case SC_FORBIDDEN:return ("Forbidden");case SC_GATEWAY_TIMEOUT:return ("Gateway Timeout");case SC_GONE:return ("Gone");case SC_HTTP_VERSION_NOT_SUPPORTED:return ("HTTP Version Not Supported");case SC_INTERNAL_SERVER_ERROR:return ("Internal Server Error");case SC_LENGTH_REQUIRED:return ("Length Required");case SC_METHOD_NOT_ALLOWED:return ("Method Not Allowed");case SC_MOVED_PERMANENTLY:return ("Moved Permanently");case SC_MOVED_TEMPORARILY:return ("Moved Temporarily");case SC_MULTIPLE_CHOICES:return ("Multiple Choices");case SC_NO_CONTENT:return ("No Content");case SC_NON_AUTHORITATIVE_INFORMATION:return ("Non-Authoritative Information");case SC_NOT_ACCEPTABLE:return ("Not Acceptable");case SC_NOT_FOUND:return ("Not Found");case SC_NOT_IMPLEMENTED:return ("Not Implemented");case SC_NOT_MODIFIED:return ("Not Modified");case SC_PARTIAL_CONTENT:return ("Partial Content");case SC_PAYMENT_REQUIRED:return ("Payment Required");case SC_PRECONDITION_FAILED:return ("Precondition Failed");case SC_PROXY_AUTHENTICATION_REQUIRED:return ("Proxy Authentication Required");case SC_REQUEST_ENTITY_TOO_LARGE:return ("Request Entity Too Large");case SC_REQUEST_TIMEOUT:return ("Request Timeout");case SC_REQUEST_URI_TOO_LONG:return ("Request URI Too Long");case SC_REQUESTED_RANGE_NOT_SATISFIABLE:return ("Requested Range Not Satisfiable");case SC_RESET_CONTENT:return ("Reset Content");case SC_SEE_OTHER:return ("See Other");case SC_SERVICE_UNAVAILABLE:return ("Service Unavailable");case SC_SWITCHING_PROTOCOLS:return ("Switching Protocols");case SC_UNAUTHORIZED:return ("Unauthorized");case SC_UNSUPPORTED_MEDIA_TYPE:return ("Unsupported Media Type");case SC_USE_PROXY:return ("Use Proxy");case 207:       // WebDAVreturn ("Multi-Status");case 422:       // WebDAVreturn ("Unprocessable Entity");case 423:       // WebDAVreturn ("Locked");case 507:       // WebDAVreturn ("Insufficient Storage");default:return ("HTTP Response Status " + status);}}public OutputStream getStream() {return this.output;}/*** Send the HTTP response headers, if this has not already occurred.*/protected void sendHeaders() throws IOException {if (isCommitted())return;// Prepare a suitable output writerOutputStreamWriter osr = null;try {osr = new OutputStreamWriter(getStream(), getCharacterEncoding());}catch (UnsupportedEncodingException e) {osr = new OutputStreamWriter(getStream());}final PrintWriter outputWriter = new PrintWriter(osr);// Send the "Status:" headeroutputWriter.print(this.getProtocol());outputWriter.print(" ");outputWriter.print(status);if (message != null) {outputWriter.print(" ");outputWriter.print(message);}outputWriter.print("\r\n");// Send the content-length and content-type headers (if any)if (getContentType() != null) {outputWriter.print("Content-Type: " + getContentType() + "\r\n");}if (getContentLength() >= 0) {outputWriter.print("Content-Length: " + getContentLength() + "\r\n");}// Send all specified headers (if any)synchronized (headers) {Iterator names = headers.keySet().iterator();while (names.hasNext()) {String name = (String) names.next();ArrayList values = (ArrayList) headers.get(name);Iterator items = values.iterator();while (items.hasNext()) {String value = (String) items.next();outputWriter.print(name);outputWriter.print(": ");outputWriter.print(value);outputWriter.print("\r\n");}}}// Add the session ID cookie if necessary
/*    HttpServletRequest hreq = (HttpServletRequest) request.getRequest();HttpSession session = hreq.getSession(false);if ((session != null) && session.isNew() && (getContext() != null)&& getContext().getCookies()) {Cookie cookie = new Cookie("JSESSIONID", session.getId());cookie.setMaxAge(-1);String contextPath = null;if (context != null)contextPath = context.getPath();if ((contextPath != null) && (contextPath.length() > 0))cookie.setPath(contextPath);elsecookie.setPath("/");if (hreq.isSecure())cookie.setSecure(true);addCookie(cookie);}
*/// Send all specified cookies (if any)synchronized (cookies) {Iterator items = cookies.iterator();while (items.hasNext()) {Cookie cookie = (Cookie) items.next();outputWriter.print(CookieTools.getCookieHeaderName(cookie));outputWriter.print(": ");outputWriter.print(CookieTools.getCookieHeaderValue(cookie));outputWriter.print("\r\n");}}// Send a terminating blank line to mark the end of the headersoutputWriter.print("\r\n");outputWriter.flush();committed = true;}public void setRequest(HttpRequest 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.getRequestURI());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();}}public void write(int b) throws IOException {if (bufferCount >= buffer.length)flushBuffer();buffer[bufferCount++] = (byte) b;contentCount++;}public void write(byte b[]) throws IOException {write(b, 0, b.length);}public void write(byte b[], int off, int len) throws IOException {// If the whole thing fits in the buffer, just put it thereif (len == 0)return;if (len <= (buffer.length - bufferCount)) {System.arraycopy(b, off, buffer, bufferCount, len);bufferCount += len;contentCount += len;return;}// Flush the buffer and start writing full-buffer-size chunksflushBuffer();int iterations = len / buffer.length;int leftoverStart = iterations * buffer.length;int leftoverLen = len - leftoverStart;for (int i = 0; i < iterations; i++)write(b, off + (i * buffer.length), buffer.length);// Write the remainder (guaranteed to fit in the buffer)if (leftoverLen > 0)write(b, off + leftoverStart, leftoverLen);}/** implementation of HttpServletResponse  */public void addCookie(Cookie cookie) {if (isCommitted())return;//  if (included)//        return;     // Ignore any call from an included servletsynchronized (cookies) {cookies.add(cookie);}}public void addDateHeader(String name, long value) {if (isCommitted())return;
//    if (included)//          return;     // Ignore any call from an included servletaddHeader(name, format.format(new Date(value)));}public void addHeader(String name, String value) {if (isCommitted())return;
//        if (included)//          return;     // Ignore any call from an included servletsynchronized (headers) {ArrayList values = (ArrayList) headers.get(name);if (values == null) {values = new ArrayList();headers.put(name, values);}values.add(value);}}public void addIntHeader(String name, int value) {if (isCommitted())return;
//    if (included)//    return;     // Ignore any call from an included servletaddHeader(name, "" + value);}public boolean containsHeader(String name) {synchronized (headers) {return (headers.get(name)!=null);}}public String encodeRedirectURL(String url) {return null;}public String encodeRedirectUrl(String url) {return encodeRedirectURL(url);}public String encodeUrl(String url) {return encodeURL(url);}public String encodeURL(String url) {return null;}public void flushBuffer() throws IOException {//committed = true;if (bufferCount > 0) {try {output.write(buffer, 0, bufferCount);}finally {bufferCount = 0;}}}public int getBufferSize() {return 0;}public String getCharacterEncoding() {if (encoding == null)return ("ISO-8859-1");elsereturn (encoding);}public Locale getLocale() {return null;}public ServletOutputStream getOutputStream() throws IOException {return null;}public PrintWriter getWriter() throws IOException {ResponseStream newStream = new ResponseStream(this);newStream.setCommit(false);OutputStreamWriter osr =new OutputStreamWriter(newStream, getCharacterEncoding());writer = new ResponseWriter(osr);return writer;}/*** Has the output of this response already been committed?*/public boolean isCommitted() {return (committed);}public void reset() {}public void resetBuffer() {}public void sendError(int sc) throws IOException {}public void sendError(int sc, String message) throws IOException {}public void sendRedirect(String location) throws IOException {}public void setBufferSize(int size) {}public void setContentLength(int length) {if (isCommitted())return;
//    if (included)//     return;     // Ignore any call from an included servletthis.contentLength = length;}public void setContentType(String type) {}public void setDateHeader(String name, long value) {if (isCommitted())return;
//    if (included)//    return;     // Ignore any call from an included servletsetHeader(name, format.format(new Date(value)));}public void setHeader(String name, String value) {if (isCommitted())return;
//    if (included)//    return;     // Ignore any call from an included servletArrayList values = new ArrayList();values.add(value);synchronized (headers) {headers.put(name, values);}String match = name.toLowerCase();if (match.equals("content-length")) {int contentLength = -1;try {contentLength = Integer.parseInt(value);}catch (NumberFormatException e) {;}if (contentLength >= 0)setContentLength(contentLength);}else if (match.equals("content-type")) {setContentType(value);}}public void setIntHeader(String name, int value) {if (isCommitted())return;//if (included)//return;     // Ignore any call from an included servletsetHeader(name, "" + value);}public void setLocale(Locale locale) {if (isCommitted())return;//if (included)//return;     // Ignore any call from an included servlet// super.setLocale(locale);String language = locale.getLanguage();if ((language != null) && (language.length() > 0)) {String country = locale.getCountry();StringBuffer value = new StringBuffer(language);if ((country != null) && (country.length() > 0)) {value.append('-');value.append(country);}setHeader("Content-Language", value.toString());}}public void setStatus(int sc) {}public void setStatus(int sc, String message) {}
}

httpconnector调用httpprocessor的process方法，通过传递socket对象，连接器解析HTTP请求头部并让servlet可以获得头部, cookies, 参数名/值等等。这就是连接器的重要作用。

3.3 core模块

StaticResourceProcessor

import ex03.pyrmont.connector.http.HttpRequest;
import ex03.pyrmont.connector.http.HttpResponse;
import java.io.IOException;public class StaticResourceProcessor {public void process(HttpRequest request, HttpResponse response) {try {response.sendStaticResource();}catch (IOException e) {e.printStackTrace();}}}

ServletProcessor

import ex03.pyrmont.connector.http.Constants;
import ex03.pyrmont.connector.http.HttpRequest;
import ex03.pyrmont.connector.http.HttpResponse;
import ex03.pyrmont.connector.http.HttpRequestFacade;
import ex03.pyrmont.connector.http.HttpResponseFacade;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 ServletProcessor {public void process(HttpRequest request, HttpResponse response) {String uri = request.getRequestURI();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);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) {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();HttpRequestFacade requestFacade = new HttpRequestFacade(request);HttpResponseFacade responseFacade = new HttpResponseFacade(response);servlet.service(requestFacade, responseFacade);((HttpResponse) response).finishResponse();}catch (Exception e) {System.out.println(e.toString());}catch (Throwable e) {System.out.println(e.toString());}}
}