package com.Select;

/*
*

*select单线程 服务器

*
*/

import java.io.IOException;

import java.net.InetSocketAddress;

import java.nio.ByteBuffer;

import java.nio.channels.ClosedChannelException;

import java.nio.channels.SelectableChannel;

import java.nio.channels.SelectionKey;

import java.nio.channels.Selector;

import java.nio.channels.ServerSocketChannel;

import java.nio.channels.SocketChannel;

import java.util.HashMap;

import java.util.Iterator;

import java.util.Map;

import java.util.Set;

public class Myselect {

    private Map<SocketChannel, String> map = new HashMap<SocketChannel, String>();

    public static void main(String[] args) {

        // TODO Auto-generated method stubnew Myselect().initsocket();

    }

    public void initsocket(){

        ServerSocketChannel ssc=null;

        Selector selector=null;

        Iterator<SelectionKey> iter=null;

        try {

            ssc = ServerSocketChannel.open();

            ssc.socket().setReuseAddress(true);

            ssc.socket().bind(new InetSocketAddress(8081));

            selector = Selector.open();

            ssc.configureBlocking(false);

            ssc.register(selector, SelectionKey.OP_ACCEPT);

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

        while (true) {

            try {

                int keys = selector.select(1000);

                if (keys <= 0)

                    continue;

                iter=null;

                Set<SelectionKey> set_key = selector.selectedKeys();

                iter= set_key.iterator();

            } catch (Exception e) {

                // TODO: handle exception

            }

            while (iter.hasNext()) {

                SelectionKey key = iter.next();

                iter.remove();

                if (key.isAcceptable()) {

                    try {

                        SocketChannel client = ssc.accept();

                        client.configureBlocking(false);

                        client.register(selector, SelectionKey.OP_READ);

                    } catch (ClosedChannelException e) {

                        // TODO Auto-generated catch block

                        e.printStackTrace();

                    } catch (IOException e) {

                        // TODO Auto-generated catch block

                        e.printStackTrace();

                    }

                } else if (key.isReadable()) {

                    SocketChannel client = (SocketChannel) key.channel();

                    ByteBuffer dst = ByteBuffer.allocate(4094);

                    StringBuffer sb = new StringBuffer();

                    int readsize = -1;

                    try {

                        while ((readsize = client.read(dst)) > 0) {

                            dst.flip();

                            sb.append(new String(dst.array(), 0, readsize));

                            dst.clear();

                            if (readsize < 0) {//对端关闭，read 返回-1，没有数据返回0，如果客户端一直没有发送数据则isReadable事件激发不了。

                                System.out.println("client "

                                        + ((InetSocketAddress) client.getRemoteAddress()).getAddress().getHostAddress()

                                        + " is closed");

                                key.cancel();//取消select 监听并关闭服务端socket.

                                client.close();

                                continue;

                            }

                            map.put(client, sb.toString());//

                            System.out.println("server read : "+sb.toString());

                            client.register(selector, SelectionKey.OP_WRITE);

                        }

                    } catch (Exception e) {

                        // TODO: handle exception

                    }

                } else if (key.isWritable()) {

                    System.out.println("coming write\n");

                    SocketChannel client = (SocketChannel) key.channel();

                    String req = map.get(client);

                    if(req==null) {

                        continue;

                    }

                    System.out.println("ready write len"+req.length());

                    String httpResponse = "HTTP/1.1 200 OK\r\n" +

                            "Content-Length: "+req.length()+"\r\n" +

                            "Content-Type: text/html\r\n" +

                            "\r\n" +req;

//                    int wcode=client.write(ByteBuffer.wrap(httpResponse.getBytes()));

                    try {//捕捉异常，客户端端可能关闭导致写异常。

                        int wcode=client.write(ByteBuffer.wrap(req.getBytes()));

                        System.out.println("write code "+wcode);

                        client.register(selector, SelectionKey.OP_READ);

                    } catch (Exception e) {

                        // TODO: handle exception

                        map.remove(client);//关闭服务器端socket，并取消监听

                        key.cancel();

                        System.out.println("client is closed!");

                        try {

                            client.close();

                        } catch (IOException e1) {

                            // TODO Auto-generated catch block

                            e1.printStackTrace();

                        }

                    }

                }

            }

        }

    }

}