手寫簡單的HttpServer基於Java nio 實現socket異步通信(請求映射注解方式)

HttpServer服務類

package javax.servlet.http.server2;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.util.Iterator;

public class HttpServer {
    private int DEFULT_PORT=8080;               //默認端口
    private boolean isShudown=true;            //服務狀態
    private ServerSocketChannel ssc;
    public HttpServer(){
        try{
            start(DEFULT_PORT);
        } catch (IOException e){
            e.printStackTrace();
        }
    }
    
    public HttpServer(int port){
        try{
            start(port);
        } catch (IOException e){
            e.printStackTrace();
        }
    }
    public void start(int port) throws IOException{
        ssc=ServerSocketChannel.open(); // 打開服務器套接字通道
        ssc.socket().bind(new InetSocketAddress(port));     //綁定到特定端口
        ssc.configureBlocking(false);                      //設置為非阻塞模式
        Selector selector=Selector.open();                 //打開一個選擇器
        ssc.register(selector, SelectionKey.OP_ACCEPT);    //向給定的選擇器注冊此通道，返回一個選擇鍵
        while(isShudown){
            /*if(selector.select(3000)==0){         //沒有請求阻塞3秒,繼續執行
                continue;
            }*/
            if(selector.select()>0){        //等待請求，請求過來繼續執行，沒有請求一直等待
                Iterator<SelectionKey> keyIter=selector.selectedKeys().iterator();          //獲取等待處理的請求
                while (keyIter.hasNext()){
                    SelectionKey key=keyIter.next();
                    new Thread(new HttpHandler(key)).run();                    // 啟動新線程處理SelectionKey
                    keyIter.remove();                                           // 處理完后，從待處理的SelectionKey迭代器中移除當前所使用的key
               }
            }
             
        } 
    }
    
    /**
     * 關閉端口
     * @throws IOException
     */
    public void stop() throws IOException{
        isShudown=false;
        //ssc.socket().close();
    }
    
    /**
     * 打開服務的主入口
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception{

        new HttpServer(2222);
    }

    
}

HttpHandler請求處理類

package javax.servlet.http.server2;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;

public class HttpHandler implements Runnable{
    private int bufferSize = 1024;
    private SelectionKey key;
    private int CODE=200;
    public HttpHandler(SelectionKey key){
        this.key = key;
    }

    /**
     * 接收連接處理
     * @throws IOException
     */
    public void handleAccept() throws IOException {
        SocketChannel clientChannel=((ServerSocketChannel)key.channel()).accept();
        clientChannel.configureBlocking(false);     //線程不阻塞
        clientChannel.register(key.selector(), SelectionKey.OP_READ|SelectionKey.OP_WRITE, ByteBuffer.allocate(bufferSize));       //注冊讀寫
        
    }
    @Override
    public void run()
    {
        // 接收到連接請求時
        if (key.isAcceptable())
        {
            try
            {
                handleAccept();
            } catch (IOException e)
            {
                e.printStackTrace();
            }

        }
        
        if (key.isReadable()&&key.isWritable())   //可讀可寫
        {
            try
            {
                HttpServletRequest ser=new HttpServletRequest(key);                //封裝Request
                HttpServletResponse serr=new HttpServletResponse(key);             //封裝Response
                HttpServlet servlet=WebApp.getServlet(ser.getUrl());               //通過映射地址獲取具體的servlet
                if(servlet==null){
                    this.CODE=404;
                }else{
                    try
                    {
                        servlet.service(ser, serr);
                    } catch (Exception e)
                    {
                        e.printStackTrace();
                        this.CODE=500;
                        StringWriter sw = new StringWriter();   
                        PrintWriter pw = new PrintWriter(sw, true);   
                        pw.flush();   
                        sw.flush(); 
                        serr.println(sw.toString());
                    }
                }
                serr.pushToClient(CODE);
                ser.close();
                serr.close();
            } catch (IOException e)
            {
                e.printStackTrace();
            }
            
        }
        
        
    }
}

HttpServlet基類

package javax.servlet.http.server2;

public abstract class HttpServlet {
    public void service(HttpServletRequest req,HttpServletResponse rep) throws Exception{
        this.doGet(req,rep);
    }
    
    protected  abstract void doGet(HttpServletRequest req,HttpServletResponse rep) throws Exception;
    protected  abstract void doPost(HttpServletRequest req,HttpServletResponse rep) throws Exception;
}

 

HttpServletRequest請求封裝類

package javax.servlet.http.server2;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

public class HttpServletRequest
{
    private final String DEFULT_CODE="UTF-8";
    private final String CRLF="\r\n";      //回車換行
    private final String SPACE=" ";
    private SocketChannel sc;
    private ByteBuffer buffer;
    private String requestInfo;
    private String method;
    private String url;
    private Map<String,List<String>> parameterMapValues;
    
    public HttpServletRequest(){
        parameterMapValues=new HashMap<String,List<String>>();
    }
    public HttpServletRequest(SelectionKey key) throws IOException{
        this();
        sc=(SocketChannel)key.channel();
        buffer=(ByteBuffer)key.attachment();
        buffer.clear();
        if(sc.read(buffer)==-1){
             sc.close();
        }else{
             buffer.flip();
             requestInfo=Charset.forName(DEFULT_CODE).newDecoder().decode(buffer).toString();
        }
         parseRequestInfo();
    }
    
    /**
     * 分析請求，主要是獲取資源地址、封裝專遞的參數
     */
    private void parseRequestInfo(){
        String paramInfo = null;
        if(requestInfo==null||"".equals(requestInfo)){
            return ;
        }
        String[] requestMessage = requestInfo.split(CRLF);        //得到請求的消息
        String[] firstLine = requestMessage[0].split(SPACE);      //獲取首行頭文件
        this.method=firstLine[0];                  //獲取提交方式
        String tempUrl=firstLine[1];               //獲取資源地址
        if(method.equals(RequestType.POST.toString())){
            this.url=tempUrl;
            paramInfo=requestMessage[requestMessage.length-1];
        }else if(method.equals(RequestType.GET.toString())){
            if(tempUrl.contains("?")){       //如果有參數
                String params[]=tempUrl.split("\\?");
                this.url=params[0];
                paramInfo=params[1];//接收請求參數
            }else
                this.url=tempUrl;
        }
        
        if(paramInfo==null||"".equals(paramInfo)){
            return ;
        }else
            parseParams(paramInfo);
    }

    /**
     * 保存傳遞的參數
     * @param paramInfo
     */
    private void parseParams(String paramInfo){
        StringTokenizer token=new StringTokenizer(paramInfo,"&");
        while(token.hasMoreTokens()){
            String keyValue =token.nextToken();
            String[] keyValues=keyValue.split("=");
            if(keyValues.length==1){
                keyValues =Arrays.copyOf(keyValues, 2);
                keyValues[1] =null;
            }
            
            String key = keyValues[0].trim();
            String value = null==keyValues[1]?null:keyValues[1].trim();
            //轉換成Map 分揀
            if(!parameterMapValues.containsKey(key)){
                parameterMapValues.put(key,new ArrayList<String>());
            }
            
            List<String> values =parameterMapValues.get(key);
            values.add(value);            
        }        
    }
    
    /**
     * 根據頁面的name 獲取對應的多個值
     * @param name   名
     */
    public String[] getParameterValues(String name){
        List<String> values=null;
        if((values=parameterMapValues.get(name))==null){
            return null;
        }else{
            return values.toArray(new String[]{});
        }
    }
    
    /**
     * 返回單個值
     * @param name 名
     * @return
     */
    public String getParameter(String name){
        String[] values =getParameterValues(name);
        if(null==values){
            return null;
        }
        return values[0];
    }
    
    /**
     * 獲取請求方法
     * @return
     */
    public String getMethod()
    {
        return method;
    }
    
    /**
     * 獲取url資源訪問地址
     * @return
     */
    public String getUrl()
    {
        return url;
    }
    /**
     * 關閉連接
     */
     void close()
    {
        try
        {
            if (sc.isOpen())
            {
                sc.close();
            }
        } catch (IOException e)
        {
            e.printStackTrace();
        }
    }
}

HttpServletResponse響應封裝類

package javax.servlet.http.server2;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.SocketChannel;
import java.util.Date;
public class HttpServletResponse
{

    //兩個常量
    public static final String CRLF="\r\n";
    public static final String BLANK=" ";
    private static final String localCharset="UTF-8";
    //正文
    private StringBuilder content;
    //存儲頭信息
    private StringBuilder headInfo;
    //存儲正文長度
    private int len =0;
    private StringBuilder bu;
    private ByteBuffer buffer;
    private SocketChannel sc;
    public HttpServletResponse(){
        bu=new StringBuilder();
        headInfo =new StringBuilder();
        content =new StringBuilder();
        len =0;
    }
    public HttpServletResponse(SelectionKey key){
        this();
        sc=(SocketChannel)key.channel();
        buffer=(ByteBuffer)key.attachment();
        buffer.clear();
        buffer.flip();
    }
    
    /**
     * 構建正文
     */
    public HttpServletResponse print(String info){
        content.append(info);
        len+=info.getBytes().length;
        return this;
    }
    
    /**
     * 構建正文+回車
     */
    public HttpServletResponse println(String info){
        content.append(info).append(CRLF);
        len+=(info+CRLF).getBytes().length;
        return this;
    }
    
    /**
     * 構建響應頭
     */
    private void createHeadInfo(int code){
        //1)  HTTP協議版本、狀態代碼、描述
        headInfo.append("HTTP/1.1").append(BLANK).append(code).append(BLANK);
        switch(code){
            case 200:
                headInfo.append("OK");
                break;
            case 404:
                headInfo.append("NOT FOUND");
                break;
            case 505:
                headInfo.append("SEVER ERROR");
                break;    
        }
        headInfo.append(CRLF);
        //2)  響應頭(Response Head)
        headInfo.append("Server:bjsxt Server/0.0.1").append(CRLF);
        headInfo.append("Date:").append(new Date()).append(CRLF);
        headInfo.append("Content-type:text/html;charset="+localCharset).append(CRLF);
        //正文長度 ：字節長度
        headInfo.append("Content-Length:").append(len).append(CRLF);
        headInfo.append(CRLF); //分隔符
    } 
    
    //推送到客戶端
    void pushToClient(int code) throws IOException{
            if(null==headInfo){
                code =500;
            }
            createHeadInfo(code);
            //頭信息+分割符
            bu.append(headInfo.toString());
            
            //正文
            bu.append(content.toString());
            buffer = ByteBuffer.wrap(bu.toString().getBytes(localCharset));
            if(sc.isOpen())
                sc.write(buffer);
            
        }
    
    /**
     * 關閉
     */
    void close(){
        try
        {
            if(sc.isOpen()){
                sc.close();
            }
            
        } catch (IOException e)
        {
            e.printStackTrace();
        }
    }
}

 

RequestType請求類型

package javax.servlet.http.server2;

public enum RequestType
{
POST    //post請求
,GET    //get請求

}

ServletContext 容器

package javax.servlet.http.server2;

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


public class ServletContext
{

    private Map<String,String>servlet;
    public ServletContext(){
        servlet=new HashMap<String,String>();
    }
    
    /**
     * 獲取servlet容器
     * @return
     */
    public Map<String, String> getServlet()
    {
        return servlet;
    }
    
}

 

WebApp功能映射處理

package javax.servlet.http.server2;

import java.util.Iterator;
import java.util.Map;
import javax.servlet.annotation.WebServlet;
import javax.servlet.util.PackageScanUtils;

public class WebApp
{

    private static ServletContext context;
    static{
        context=new ServletContext();
        Map<String,String>servlet=context.getServlet();
        Iterator<Class<?>>clas=PackageScanUtils.getClasses("javax.servlet.http.server2",true).iterator();
        while(clas.hasNext()){
            Class<?>cla=clas.next();
            WebServlet ws=cla.getAnnotation(WebServlet.class);
            if(ws!=null){
                servlet.put(ws.value(), cla.getName());
            }
        }
    }
    
    /**
     * 獲取url地址
     * @param url
     * @return
     */
    public static HttpServlet getServlet(String url)
    {
        Map<String,String>temp=context.getServlet();
        if(temp.containsKey(url)){
            try
            {
                return (HttpServlet)Class.forName(temp.get(url)).newInstance();
            } catch (InstantiationException e)
            {
                e.printStackTrace();
            } catch (IllegalAccessException e)
            {
                e.printStackTrace();
            } catch (ClassNotFoundException e)
            {
                e.printStackTrace();
            }
        }
        return null;
    }
}

Message 狀態

package javax.servlet.cod;

public class Message
{

    public static String message404(){
        StringBuilder conetxt=new StringBuilder();
        conetxt.append("<html><head><title>lishenglin - Error report</title><style><!--H1");
        conetxt.append("{font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:22px;} H2");
        conetxt.append("{font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:16px;} H3");
        conetxt.append("{font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:14px;} BODY");
        conetxt.append("{font-family:Tahoma,Arial,sans-serif;color:black;background-color:white;} B");
        conetxt.append("{font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;} P");
        conetxt.append("{font-family:Tahoma,Arial,sans-serif;background:white;color:black;font-size:12px;}A {color : black;}A.name {color : black;}HR");
        conetxt.append("{color : #525D76;}--></style> </head><body><h1>HTTP Status 404 - </h1><HR size=\"1\" noshade=\"noshade\"><p><b>type</b> Status");
        conetxt.append("report</p><p><b>message</b> <u></u></p><p><b>description</b> <u>The requested resource is not available.</u></p><HR size=\"1\"");
        conetxt.append("noshade=\"noshade\"><h3>lishenglin</h3></body></html>");
        return conetxt.toString();
        
    }
    
}

PackageScanUtils 掃描class

package javax.servlet.util;

import java.io.File;
import java.io.FileFilter;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URL;
import java.net.URLDecoder;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Set;

public class PackageScanUtils
{
    
        /**
         * 獲取class集合
         * @param packName         包名
         * @param scanSubdirectory  掃描子目錄
         * @return
         */
    public static Set<Class<?>> getClasses(String packName,boolean scanSubdirectory)
    {

        Set<Class<?>> classes = new LinkedHashSet<Class<?>>(); // 裝載class集合
        String packageName = packName; // 獲取包的名字 並進行替換
        String packageUrlName = packageName.replace('.', '/');
        Enumeration<URL> urls; // 定義一個枚舉的集合 並進行循環來處理這個目錄下的class
        try
        {
            urls = Thread.currentThread().getContextClassLoader().getResources(packageUrlName);

            // 循環迭代下去
            while (urls.hasMoreElements())
            {

                URL url = urls.nextElement(); // 獲取下一個元素

                String protocol = url.getProtocol(); // 得到協議的名稱,比如http、file

                if ("file".equals(protocol))
                { // 如果是以文件的形式保存在服務器上

                    String filePath = URLDecoder.decode(url.getFile(), "UTF-8"); // 獲取包的物理路徑
                    // 以文件的方式掃描整個包下的文件 並添加到集合中
                    findClassesInPackageByFile(packageName, filePath, scanSubdirectory, classes);
                }
            }
        } catch (IOException e)
        {
            e.printStackTrace();
         }

        return classes;
    }
    
    /**
     * 以文件的方式掃描整個包下的文件 並添加到集合中
     * @param packageName   包名
     * @param packagePath   包路徑
     * @param scanSubdirectory     是否掃描子目錄
     * @param classes        class集合
     * @throws FileNotFoundException 
     */
    public static void findClassesInPackageByFile(String packageName, String packagePath, final boolean scanSubdirectory, Set<Class<?>> classes) throws FileNotFoundException
    {

        File dir = new File(packagePath); // 獲取此包的目錄 建立一個File
        File[] dirfiles = dir.listFiles(new FileFilter()
        { // 如果存在 就獲取包下的所有文件 包括目錄 

            public boolean accept(File file)
            { // 自定義過濾規則 如果可以循環(包含子目錄) 或則是以.class結尾的文件(編譯好的java類文件)
                return (scanSubdirectory && file.isDirectory()) || (file.getName().endsWith(".class"));
            }
        });

        for (File file : dirfiles)
        { // 循環所有文件
            
            if (file.isDirectory())
            { // 如果是目錄 則繼續掃描
                findClassesInPackageByFile(packageName==""? file.getName():packageName + "." + file.getName(), file.getAbsolutePath(), scanSubdirectory, classes);
            } else
            { // 如果是java類文件 去掉后面的.class 只留下類名

                String className = file.getName().substring(0, file.getName().length() - 6);
                try
                {
                    if("".equals(packageName)){
                        classes.add(Thread.currentThread().getContextClassLoader().loadClass(className));
                    }else{
                        classes.add(Thread.currentThread().getContextClassLoader().loadClass(packageName + '.' + className));
                    }
                } catch (ClassNotFoundException e)
                {
                    e.printStackTrace();
                }
            }
        }
    }
    
    public static void main(String[] args)
    {
        Set<Class<?>> clas=PackageScanUtils.getClasses("cn.javax",true);
        Iterator<Class<?>>cla=clas.iterator();
        while(cla.hasNext()){
            /*Annotation[]ann=cla.next().getAnnotations();
            for(Annotation a:ann){
                if(a instanceof WebServlet){
                    System.out.println(((WebServlet) a).value());
                }
            }*/
            System.out.println(cla.next().getName());
        }
    }
}

 

MyServlet 測試servlet

package javax.servlet.http.server2;

import javax.servlet.annotation.WebServlet;

@WebServlet("/myservlet")
public class Myservlet extends HttpServlet
{
    

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse rep) throws Exception
    {
        this.doPost(req, rep);
        
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse rep) throws Exception
    {
        String name=req.getParameter("name");
        rep.println("獲取的參數name="+name);
        rep.println("請求的url是:"+req.getUrl());
        
    }
}

WebServlet簡單注解

package javax.servlet.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
/**
 * webServlet注解
 * @author 李聖霖
 * @date 2017年3月28日
 */
public abstract @interface WebServlet
{
    public abstract java.lang.String value() default "";        //映射地址
}

 

測試