手写服务器总结
搭建框架
…………………
实现
编写web.xml
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<servlet>
<servlet-name>login</servlet-name>
<servlet-class>com.szxy.httpserver.servlet.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>login</servlet-name>
<url-pattern>/login</url-pattern>
<url-pattern>/log</url-pattern>
</servlet-mapping>
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实体类保存解析xml中的信息
Entity类:servlet-name,servlet-class
Mapping类:servlet-name,url-pattern
解析xml
dom4j解析xml
Entity:servlet-name,servlet-class
Entity通过String name，String clazz两个成员变量保存web.xml中的\servlet-name,servlet-class
Mapping:servlet-name,url-pattern，
Mapping通过String name，和List urlPattern集合两个成员变量保存web.xml中的\servlet-name,url-pattern，
ServletContext类
上下文，是一个容器，描述Entity与Mapping之间的关系
该类的成员变量
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| private Map<String, String> servlet; //key是servlet-name,value是servlet-class
private Map<String, String> mapping; //key是url-pattern,value是servlet-name
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WebApp类
1）将Entity和Mapping中的servlet-name,servlet-class,url-pattern,servlet-name
保存到ServletContext类的成员变量中。
请求路径作为key,获取servlet-name值，获取servlet-name
servlet-name作为key,获取servlet的 全路径名(包名+类名)
1） 反射创建Servlet
可以通过全路径名反射创建Servlet对象
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String servletName = context.getMapping().get(url);
String servletClass = context.getServlet().get(servletName);
Class<?> clazz = Class.forName(servletClass);
servlet = (Servlet) clazz.newInstance();
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servlet
建立抽象类Servlet
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| public abstract class Servlet {
public void service(Request req, Response rep)throws Exception{
this.doGet(req, rep);
this.doPost(req, rep);
}
public abstract void doGet(Request req, Response rep) throws Exception;
public abstract void doPost(Request req, Response rep) throws Exception;
}
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处理请求的Servlet继承Servlet
例：登录LoginServlet
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| public class LoginServlet extends Servlet{
@Override
public void doGet(Request req, Response rep) throws Exception {
String name = req.getParater("username");
String pwd = req.getParater("pwd");
if("bjsxt".equals(name) && "123".equals(pwd)){
rep.println(name + "登录成功");
}else{
rep.println("账号或者密码不正确");
}
}
@Override
public void doPost(Request req, Response rep) throws Exception {
}
}
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封装Request对象(浏览器的请求)
通过输入流获取浏览器的请求信息，然后根据HTTP协议，进行请求信息的处理
从请求信息中获取请求方式，路径，参数，
例：GET请求和POST请求的信息
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| GET /log?username=bj&pwd=123&hobby=ball HTTP/1.1
Host: localhost:8888
Connection: keep-alive
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.90 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
Accept-Encoding: gzip, deflate, br
Accept-Language: zh-CN,zh;q=0.9
POST /log HTTP/1.1
Host: localhost:8888
Connection: keep-alive
Content-Length: 30
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Origin: null
Content-Type: application/x-www-form-urlencoded
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.90 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
Accept-Encoding: gzip, deflate, br
Accept-Language: zh-CN,zh;q=0.9
username=bj&pwd=123&hobby=ball
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请求参数的乱码问题
处理中文，因为浏览器对中文进行了编码，因此需要解码
服务器端获取到发过来的请求参数默认使用ISO8859-1进行解码操作，中文一定有乱码问题
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| //value是请求参数，code是编码
return URLDecoder.decode(value, code);//decode(keyValues[1].trim(), "utf-8")
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封装Response对象(服务器的响应)
1.严格根据HTTP协议封装响应信息
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| //响应头
//协议，状态码，描述
headInfo.append("HTTP1.1").append(BLANK).append(code).append(BLANK).append("");
headInfo.append(CRLF);
headInfo.append("Content-Type:text/html;charset=utf-8").append(CRLF);
headInfo.append("Content-Length:"+length).append(CRLF);
headInfo.append(CRLF);
//响应正文
content.append(“<!DOCTYPE html><html><head><title>登录响应</title></head><body>登录成功</body></html>”).append(CRLF);
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2.响应正文可以调用Response类中的println(String info)进行设置
content.append(info).append(CRLF);
封装分发器Dispatcher
Dispatcher是一个请求与响应,并实现了Runnable接口
通过客户端连接的对象client,初始化Request和Response对象
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| req = new Request(client.getInputStream());
rep = new Response(client.getOutputStream());
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run()方法实现
1.根据请求信息获取路径，
2.根据路径通过反射创建servlet
3.调用servlet的service()方法处理请求
4.rep.pushToClient(code);//响应，将封装后的Response信息发送给客户端
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| public void run() {
Servlet servlet = WebApp.getServlet(req.getUrl());
if(servlet == null){
this.code = 404;
}else{
try {
servlet.service(req, rep);
} catch (Exception e) {
e.printStackTrace();
this.code = 500;
}
}
rep.pushToClient(code);
IOCloseUtil.closeAll(client);
}
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ServerSocket服务器
创建一个ServelSocket对象，监听8888端口
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| server = new ServerSocket(port);
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循环接收客户端请求，接收到请求，创建一个线程代理Dispatcher对象处理请求
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| while(!isShutDown){
Socket client = server.accept();
Dispatcher dis = new Dispatcher(client);
new Thread(dis).start();
}
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解决浏览器请求的icon
该请求是浏览器默认发送的:http://localhost:8888/favicon.ico
解决：
1.在web.xml中配置路径
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| <servlet>
<servlet-name>favicon</servlet-name>
<servlet-class>com.szxy.httpserver.servlet.FaviconServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>favicon</servlet-name>
<url-pattern>/favicon.ico</url-pattern>
</servlet-mapping>
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2.创建FaviconServlet类继承Servlet