從這章開始我都不知道該怎麼寫了。代碼太多了,肯定沒辦法貼出來。我只能大概介紹一下這章做了些什麼工作。
首先這章加了一個用來啓動的類BootStrap,加了一個HttpConnector類,這個HttpConnector類做的工作是創建一個ServerSocket,有請求來了就用serversocket的accept方法來創建一個socket,不同與之前HttpServer的地方是:HttpConnector接下來把剩餘的工作交給了HttpProcessor類來處理。
先看看BootStrap和HttpConnector的代碼:
package ex03.pyrmont.startup;
import ex03.pyrmont.connector.http.HttpConnector;
public final class Bootstrap {
public static void main(String[] args) {
HttpConnector connector = new HttpConnector();
connector.start();
}
}
package ex03.pyrmont.connector.http;
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 socket
Socket socket = null;
try {
socket = serverSocket.accept();
}
catch (Exception e) {
continue;
}
// Hand this socket off to an HttpProcessor
HttpProcessor processor = new HttpProcessor(this);
processor.process(socket);
}
}
public void start() {
Thread thread = new Thread(this);
thread.start();
}
}
由於HttpProcessor類中的代碼太多,在這裏貼一下processor方法,其他的比較容易理解。
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 parse
request = new HttpRequest(input);
// create HttpResponse object
response = 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 socket
socket.close();
// no shutdown for this application
}
catch (Exception e) {
e.printStackTrace();
}
}
後面的處理靜態資源和動態的servlet的地方沒多大改動。前面用一個SocketInputStream把socket.getInputStream()包裝起來了,包裝後的socketInputStream有一些解析request的方法,我認爲這裏大概知道作用就可以了,因爲解析的過程比較煩瑣,而且IO操作大家都會用,只是這裏比較麻煩而已。
private HttpRequest request;
private HttpRequestLine requestLine = new HttpRequestLine();
private HttpResponse response;
這是HttpProcessor類中的部分屬性,Processor類中的parseRequest()和parseHeaders方法對request進行了解析,包括請求頭,查詢字符串,方法名,jsessionid等,解析後將相應的值設到request實例中。
接下來一個點是ServletProcessor中的process方法,在這個方法裏面用了一個Facade(門面),把request和request用相應的Facade類包裝起來,然後將Facade傳到servlet的service方法。主要目的是屏蔽原始類的一些方法,因爲這裏有些方法只是解析的時候用到,傳到serlvet中後,不能被servlet programmer調用,因此需要屏蔽掉,如下:
servlet = (Servlet) myClass.newInstance();
HttpRequestFacade requestFacade = new HttpRequestFacade(request);
HttpResponseFacade responseFacade = new HttpResponseFacade(response);
servlet.service(requestFacade, responseFacade);
((HttpResponse) response).finishResponse();
所謂的屏蔽,就是Facade類實現了和原始類同樣的接口,在Facade類中保存着一個原始類的實例,在Facade的每個方法中調用原始類的方法。如下所示:
public class HttpRequestFacade implements HttpServletRequest{
public Object getAttribute(String name) {
return request.getAttribute(name);
}
。。。。。
}
白天上班,晚上回來一點時間,實在是累,我也明白自己寫得很爛,不過還是希望能夠幫到一些人。