web到service简单原理例子

package com.lsw.server;import java.io.*;import java.net.*;import java.util.HashMap;import java.util.Map;/* * 关于服务器，除了httpServer1类，还定义了一个Servlet接口，这个接口有一个init()和一个service()方法 * init()方法为初始化方法，当HTTPServer1类创建了该接口的类的一个实例后，就会立即调用该实例的init()方法 * service()方法：用户响应HTTP的请求，产生具体的HTTP响应结果。 * HTTPServer1服务器在响应HTTP请求时会调用servlet接口的特定类的service()方法 * 所谓web服务器动态执行程序代码。在这个例子中就是指httpServer1在运行时动态加载Servlet接口的实现类，创建他的实例。然后调用他的相关方法。 * HTTPServer1在其实现中利用了java语言的动态加载类的功能 *///动态执行public class HTTPServer1 { ???//存放selvlet实例的缓存 ???private static Map servletCache = new HashMap(); ???????public static void main(String[] args){ ???????int port; ???????ServerSocket serverSocket; ???????????????try{ ???????????port = Integer.parseInt(args[0]); ???????????System.out.println("默认端口是： " + port); ???????} ???????catch(Exception e){ ???????????System.out.println("默认端口8080"); ???????????port = 8080; ???????} ???????????????try{ ???????????//创建监听端口 ???????????serverSocket = new ServerSocket(port); ???????????System.out.println("服务器正在监听端口： " + serverSocket.getLocalPort()); ???????????while(true){ ???????????????try{ ???????????????????//等待客户的链接请求 ???????????????????final Socket socket = serverSocket.accept(); ???????????????????System.out.println("建立了一个与客户的新的TCP连接，该客户的地址为: " + socket.getInetAddress() ???????????????????????????+ " 端口为 : " + socket.getPort()); ???????????????????//响应客户请求 ???????????????????service(socket); ???????????????} ???????????????catch(Exception e){ ???????????????????e.printStackTrace(); ???????????????} ???????????} ??????????????????????} ???????catch(Exception e){ ???????????e.printStackTrace(); ???????} ???} ???????public static void service(Socket socket) throws Exception{ ???????//读取HTTP请求信息 ???????InputStream socketIn = socket.getInputStream(); //获得输入流 ???????//睡眠500毫秒，等待http请求 ???????Thread.sleep(500); ???????int size = socketIn.available(); ???????byte[] buffer = new byte[size]; ???????socketIn.read(buffer); ???????String request = new String(buffer); ???????//打印http请求数据 ???????System.out.println("客户端请求的数据为： " +request); ???????????????//解析http请求 ???????//获得http请求第一行 ???????String firstLineOfRequest = request.substring(0,request.indexOf("\r\n")); ???????System.out.println("firstLineOfRequest= " +firstLineOfRequest); ???????//解析http请求的第一行 ???????String[] parts = firstLineOfRequest.split(" "); ???????//解析http请求这种的uri ???????String uri = parts[1]; ???????System.out.println("解析http请求这种的uri=" + uri); ???????System.out.println("截图的值为=" + uri.substring(0, 1).toString()); ???????String flag = uri.substring(0, 1).toString(); ???????if(flag.equals("/")){ ???????????System.out.println("此请求是从浏览器发起的请求"); ???????????uri = uri.substring(1).toString(); ???????} ??????????????????System.out.println("解析http请求这种的uri=" + uri); ???????????????//如果请求调用servlet,则动态调用servlet的service方法 ???????if(uri.indexOf("HttpTest") != -1){ ???????????//获得servlet的名字 ???????????String servletName = null; ???????????if(uri.indexOf("?") != -1) ???????????????servletName = uri.substring(uri.indexOf("HttpTest/")+8, uri.indexOf("?")); ???????????else ???????????????servletName = uri.substring(uri.indexOf("HttpTest/")+8, uri.length()); ???????????flag = ""; ???????????flag = servletName.substring(0, 1).toString(); ???????????if(flag.equals("/")){ ???????????????servletName = servletName.substring(1).toString(); ???????????} ???????????//尝试从servlet缓存中回去servlet对象 ???????????Servlet servlet = (Servlet)servletCache.get(servletName); ???????????//如果servlet缓存在这种不存在servlet对象，则创建他，并把他放在servlet缓存中 ???????????if(servlet == null){ ???????????????servlet = (Servlet)Class.forName("com.lsw.server."+servletName).newInstance(); ???????????????servlet.init(); ???????????????servletCache.put(servletName, servlet); ???????????} ???????????????????????//调用servlet的service()方法 ???????????servlet.service(buffer, socket.getOutputStream()); ???????????????????????//睡眠1秒等待接收http响应结果 ???????????Thread.sleep(1000); ???????????socket.close(); ???????????return ; ???????} ???????????}}

package com.lsw.server;import java.io.OutputStream;public interface Servlet { ???public void init() throws Exception; ???public void service(byte[] requestBuffer,OutputStream out) throws Exception;}

package com.lsw.server;import java.io.OutputStream;public class HelloServlet implements Servlet { ???@Override ???public void init() throws Exception { ???????System.out.println("HelloServlet is inited"); ???} ???@Override ???public void service(byte[] requestBuffer, OutputStream out) ???????????throws Exception { ???????String request = new String(requestBuffer); ???????//打印http请求数据 ???????System.out.println("客户端请求的数据为： " +request); ???????????????//解析http请求 ???????//获得http请求第一行 ???????String firstLineOfRequest = request.substring(0,request.indexOf("\r\n")); ???????System.out.println("firstLineOfRequest= " +firstLineOfRequest); ???????//解析http请求的第一行 ???????String[] parts = firstLineOfRequest.split(" "); ???????//获得http请求中的请求方式 ???????String method = parts[0]; ???????System.out.println("解析http请求方式method=" + method); ???????//解析http请求这种的uri ???????String uri = parts[1]; ???????System.out.println("解析http请求这种的uri=" + uri); ???????System.out.println("截图的值为=" + uri.substring(0, 1).toString()); ???????String flag = uri.substring(0, 1).toString(); ???????if(flag.equals("/")){ ???????????System.out.println("此请求是从浏览器发起的请求"); ???????????uri = uri.substring(1).toString(); ???????} ??????????????????System.out.println("解析http请求这种的uri=" + uri); ???????????????//获得请求参数username ???????String username = null; ???????//如果请求方式为get，则请求参数紧跟http请求的第一行的uri的后面 ???????if(method.equalsIgnoreCase("get") && uri.indexOf("username=")!=-1){ ???????????//假定uri="servlet/HelloServlet?username=Tom&password=1234" ???????????//parameters="username=Tom&password=1234" ???????????String parameters = uri.substring(uri.indexOf("?"),uri.length()); ???????????//parts={"username=Tom","password=1234"} ???????????parts = parameters.split("&"); ???????????//parts={"username","Tom"} ???????????parts = parts[0].split("="); ???????????username = parts[1]; ???????} ???????????????//如果请求方式为POST,则请求参数位于http请求的正文中 ???????if(method.equalsIgnoreCase("post")){ ???????????int locate = request.indexOf("\r\n\r\n"); ???????????//获得响应正文 ???????????String content = request.substring(locate+4,request.length()); ???????????if(content.indexOf("username=")!=-1){ ???????????????//假定content="username=Tom&password=1234" ???????????????//parts="username=Tom&password=1234" ???????????????parts = content.split("&"); ???????????????parts = parts[0].split("="); ???????????????username = parts[1]; ???????????} ???????????????????} ???????????????//创建发送响应的http响应 ???????//发送http响应第一行" ???????out.write("HTTP/1.1 200 OK\r\n".getBytes()); ???????//发送http响应头 ???????out.write("Content-Type:text/html\r\n\r\n".getBytes()); ???????//发送http响应正文 ???????out.write("<html><head><title>HelloWorld</title></head></body>".getBytes()); ???????out.write(new String("<h1>Hello:" + username + "</h1></body></head></html>").getBytes()); ???}}