标签：http协议 servlet tomcat 源码 读书笔记
另外,StringManager的产生是单例模式,大家可以看看源码
我们这一章的servlet代码如下
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
public class ModernServlet extends HttpServlet {
public void init(ServletConfig config) {
System.out.println("ModernServlet -- init");
}
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<head>");
out.println("<title>Modern Servlet</title>");
out.println("</head>");
out.println("<body>");
out.println("<h2>Headers</h2");
Enumeration headers = request.getHeaderNames();
while (headers.hasMoreElements()) {
String header = (String) headers.nextElement();
out.println("<br>" + header + " : " + request.getHeader(header));
}
//省略部分request信息
out.println("</body>");
out.println("</html>");
}
}
系统提炼出来了一个Bootstrap类,加载HttpConnector类,调用其start()方法
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();
}
}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();
}
}
input = new SocketInputStream(socket.getInputStream(), 2048);
SocketInputStream是一个实现了InputStream接口的包装类,我们之所以用SocketInputStream,就是为了用它的readRequestLine()方法readHeader方法。前者能读出request请求的请求方法,uri和请求协议,后者能读出请求头。
parseRequest(input, output);
parseHeaders(input);
这两个方法是process方法的核心,也可以说是整个第三章的核心。往简单的说,这两个方法干的事就是解析http请求填充HttpRequst对象,当然这里面有很多很多细节的东西。
这部分说简单很简单,说麻烦也巨麻烦,大体来说就是五个部分
1读取套接字的输入流
就是下面这行代码
input = new SocketInputStream(socket.getInputStream(), 2048);
大家有兴趣可以看看readRequestLine的源代码,不过不必深究。
2解析请求行(就是 http请求的第一行 包括请求方法 uri 协议版本)
3解析请求头
4解析Cookie
5获取参数(就是前文提到的lazy load)
public PrintWriter getWriter() throws IOException {
// autoflush is true, println() will flush,
// but print() will not.
writer = new PrintWriter(output, true);
return writer;
}public PrintWriter getWriter() throws IOException {
ResponseStream newStream = new ResponseStream(this); // this 指代HttpResopnse
newStream.setCommit(false);
OutputStreamWriter osr =
new OutputStreamWriter(newStream, getCharacterEncoding());
writer = new ResponseWriter(osr);
return writer;
}
How Tomcat Works读书笔记三-------连接器
标签：http协议 servlet tomcat 源码 读书笔记
原文地址：http://blog.csdn.net/dlf123321/article/details/40180563
