【转载】tomcat原理

转载地址：https://blog.csdn.net/u014795347/article/details/52328221?locationNum=2&fps=1

以下代码纯属本人复制，而且没复制全，并且没有进行手打，实在是不走心，在此贴上原文链接：

https://blog.csdn.net/u014795347/article/details/52328221?locationNum=2&fps=1

并再次对原作者表示感谢，其中url切割的正则有些许问题，以后会重新书写补充：

说下思路：

什么是容器？：我理解的就是对象实例化的载体，对象在容器中进行类加载与实例化，我们就能够访问内存中的对象啦~

实现方式？

简单来说就是：socket监听+xml读取标签+反射实例化对象

代码如下：

package com.test.catalina.run;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.ServerSocket;
import java.net.Socket;
/**
 * 这里只实现简单的参数获取与servlet类加载
 * 更深层次可以添加多线程，封装renquest，reponse，解析配置文件等等
 * @author Administrator这个地方原先是原作者的名字
 *
 */
public class CatalinaContainer {

	private int port=8090;
	private String address="localhost";

	private ServerSocket  serverSocket;
	public static void main(String[] args) {
		try {
			new CatalinaContainer ().start();
		} catch (IOException | InstantiationException e) {
			e.printStackTrace();
		}
	}

	//开启
	public void start() throws IOException, InstantiationException{
		serverSocket = new ServerSocket(port);
		while(true){
			Socket socket = serverSocket.accept();
			BufferedReader bReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
			String line = bReader.readLine();
			 if (!(null==line)) {
                 ClintRequestBean requestBean = new ClintRequestBean(line);
                 System.out.println("客户端请求："+requestBean.toReadString());
                 System.out.println("请求参数[路径]："+requestBean.getRequestParm().get("path"));
                 System.out.println("请求参数[参数表]："+requestBean.getRequestParm().get("attrs"));
                 ClassLoader classLoader = ClassLoader.getSystemClassLoader();
                 try {
                     classLoader.loadClass("cn.wwyxxmiemie.littletomcat.exclass.ExClass");
                     System.out.println("动态加载ExClass类--成功");
                 } catch (ClassNotFoundException e) {
                     e.printStackTrace();
                     System.out.println("动态加载ExClass类--失败");
                 }
                 Class<?> exClass = null;
                 try {
                     exClass = Class.forName("cn.wwyxxmiemie.littletomcat.exclass.ExClass");
                     System.out.println("动态初始化ExClass类--成功");
                 } catch (ClassNotFoundException e) {
                     e.printStackTrace();
                     System.out.println("动态初始化ExClass类--失败");
                 }
                 Method method;
                 try {
                     method = exClass.getMethod("test", null);
                     System.out.println("得到ExClass对象的"+method.getName()+"方法");
                     try {
                         System.out.println("执行ExClass对象的"+method.getName()+"方法");
                         method.invoke(exClass.newInstance(), null);
                     } catch (IllegalAccessException e) {
                         e.printStackTrace();
                     } catch (IllegalArgumentException e) {
                         e.printStackTrace();
                     } catch (InvocationTargetException e) {
                         e.printStackTrace();
                     }
                 } catch (NoSuchMethodException e) {
                     e.printStackTrace();
                 } catch (SecurityException e) {
                     e.printStackTrace();
                 }
             }
             bReader.close();
             socket.close();  

		}

	}

}

package com.test.catalina.run;

import java.util.HashMap;
import java.util.Map;

public class ClintRequestBean {
	//以一个请求举例:http://127.0.0.1/www/qqq/eee
    private String protocol;//协议类型(eg:http)
    private String protocolVersion;//协议版本(eg:1.1)
    private String data;//请求数据(eg:/www/qqq/eee)
    private String method;//请求方法:(eg:GET)  

    /**
     * 客户端请求实体构造方法
     * @param protocol 协议类型 (eg:http)
     * @param protocolVersion 协议版本 (eg:1.1)
     * @param data 请求数据 (eg:/www/qqq/eee)【必须以‘/’分隔】
     * @param method 请求方法 (eg:GET)
     */
    public ClintRequestBean(String protocol, String protocolVersion, String data, String method) {
        super();
        this.protocol = protocol;
        this.protocolVersion = protocolVersion;
        this.data = data;
        this.method = method;
    }
    /**
     * 客户端请求实体构造方法
     * @param request 请求链接，一般针对一条完整的http链接
     */
    public ClintRequestBean(String request){
        super();
        String [] requestString = request.split(" ");
        this.method = requestString[0];
        this.data = requestString[1];
        String [] proAndVer = requestString[2].split("/");
        this.protocol = proAndVer[0];
        this.protocolVersion = proAndVer[1];
    }  

    /**
     * 转化为可读String用于分析请求
     * @return
     */
    public String toReadString(){
        return "ClintRequestBean [protocol=" + protocol + ", protocolVersion=" + protocolVersion + ", data=" + data
                + ", method=" + method + "]";
    }  

    /**
     * 得到请求的参数
     * @return map[请求路径|参数map]
     */
    public Map<String, Object> getRequestParm(){
        Map<String,Object> map = new HashMap<>();
        String [] parms =null;
        if(data.contains("\\?")){
        	parms = data.split("\\?");
            map.put("path", parms[0]);
        }

        Map<String, String> attrs = new HashMap<>();
        String[] kvs =null;
        if(data.contains("&")){
        	kvs =parms[1].split("&");
            for (String string : kvs) {
                String [] kv = string.split("=");
                attrs.put(kv[0], kv[1]);
            }
            map.put("attrs", attrs);
        }

        return map;
    }  

    public String getProtocol() {
        return protocol;
    }
    public void setProtocol(String protocol) {
        this.protocol = protocol;
    }
    public String getProtocolVersion() {
        return protocolVersion;
    }
    public void setProtocolVersion(String protocolVersion) {
        this.protocolVersion = protocolVersion;
    }
    public String getData() {
        return data;
    }
    public void setData(String data) {
        this.data = data;
    }
    public String getMethod() {
        return method;
    }
    public void setMethod(String method) {
        this.method = method;
    }
    @Override
    public String toString() {
        return this.method+" "+this.data+" "+this.protocol+"/"+this.protocolVersion;
    }
}