java考试复习

假设你的IP地址是192.168.0.100，现在需要探测目标C类网络（222.24.16.0）中主机可连通数，将可连通主机的IP地址保存在文件中（学号-姓名.dat）。

思路：

1）  一个C类网络主机数254台，必须开启多线程，设立共享的资源主机号

线程的构成方法中，至少包括 （线程名称、共享资源）

class GetPort{

         private int host = 0;

         (                      ) int getHost(){

                   return (                    );

    }

}

 

class ScanThread extends Thread{

         public ScanThread(String threadName, GetPort gp)

         public void run(){

                  ……………..

         }

}

2）  你的IP地址是内网地址，目标网络是外网，在探测过程中可能受到防火墙的阻塞，建议采用ping的方法，根据返回的字符串判断 目标主机是否能连通

Process pro = Runtime.getRuntime().exec("ping " + ipAddress);

BufferedReader buf = new BufferedReader(

                    new InputStreamReader(pro.getInputStream()));

要逐行读取，判断是否能连通目标主机

3）  将可连通的IP地址保存在  学号-姓名.dat 中

设主机IP为 String host

FileOutputStream fos = new FileOutputStream(             

fos.write(主机IP的字节数组形式)

 

我的答案

package com.zhu.experiment1;
public class GetHost{
 private int host = 0;
   public GetHost(){ }
   synchronized int add(){
      return ++host; 
    }  
}



package com.zhu.experiment1;

import java.io.BufferedReader;
import java.io.File;
import java.io.InputStreamReader;
import java.io.RandomAccessFile;
import java.net.InetAddress;
public class ScanThread extends Thread{ 
 private GetHost host ; 
 private String netid;

 public ScanThread(String netid, GetHost host){
        this.host = host;  
       this.netid = netid;
 }

 
 public void run(){
     try{
         int i;
         while((i = host.add()) < 255) {
         String ip = netid + "." + i;
         RandomAccessFile raf = new RandomAccessFile(new File("E:\\04172066-刘鑫海.dat"), "rw");

         Process pro = Runtime.getRuntime().exec("ping " + ip);
         BufferedReader buf = new BufferedReader(
                             new InputStreamReader(pro.getInputStream()));

              String line;
         while ((line = buf.readLine()) != null) {
                if(line.indexOf(ip) > 0){
                      raf.seek(raf.length());
                    raf.writeBytes(ip + "\r\n");
                }
             }
         }
     }catch(Exception e){
          e.printStackTrace();
     }
    }
}

         

package com.zhu.experiment1;
public class SumDemo{
 public static void main(String [] args) throws Exception{
 GetHost host = new GetHost();
 ScanThread st1 = new ScanThread("222.24.16", host);   
 st1.start();
 st1.join();    
 }
}

有以下学生信息info.xml，采用NIO方式转存到 学号-姓名.txt 文件中

<?xml version="1.0" encoding="utf-8"?>

<students>

           <student>

                    <id>12345</id>

                    <name>宋江</name>

                    <major>行政管理</major>

           </student>

           <student>

                    <id>23456</id>

                    <name>吴用</name>

                    <major>计算机</major>

           </student>

</students>

1）  采用DOM4J的解析方法，引用以下类库

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

 

基本操作

SAXReader reader = new SAXReader();
Document document = reader.read("info.xml");

Element element = document.getRootElement();

遍历的方法

public static void treeWalk(Element element) {

     for ( int i = 0, size = element.nodeCount(); i < size; i++ ) {
　　　　Node node = element.node(i);
　　　　if ( node instanceof Element ) {
　　　　　　System.out.println(node.getName() + "-" + node.getText());
　　　　　　treeWalk( (Element) node );
} } }

2）  NIO的使用方法

RandomAccessFile raf = new RandomAccessFile

FileChannel fc = raf.getChannel();   获得channel

ByteBuffer buf = ByteBuffer.allocate(64);

将xml中数据put到buf中，加载完毕后要调用 ByteBuffer.flip 方法

再将buf数据write到channel中 

while(buf.hasRemaining()) {

    channel.write(buf);

}

我的答案

public class Util {

    public static void main(String[] args) throws java.io.IOException{

        Person p1 = new Person("04172066","刘鑫海",22);

        java.io.File file = new java.io.File("C:\\04172066刘鑫海.txt");

        java.io.BufferedWriter bw = new java.io.BufferedWriter(new java.io.OutputStreamWriter(new java.io.FileOutputStream(file)));

        bw.write("学号：" + p1.id);

        bw.write("\r\n姓名：" + p1.name);

        bw.write("\r\n性别：" + p1.age);

        bw.flush();

        bw.close();

    }

}

class Person{

    public String id;

    public String name;

    public int age;

    public Person(String id, String name, int age){

        this.id = id;

        this.name = name;

        this.age = age;

    }

}

编写 一对一 的服务器和客户端程序

1）  服务器端开启8080端口，并只接收1个客户端的连接

2）  服务器确认客户端连接后，发送“ welcome to my Server”字符串

3）  客户端收到欢迎信息后，发送 你的姓名和学号。

我的答案
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.InetAddress;
import java.net.Socket;
public class Client {
 public static void main(String[] args)throws Exception 
 {
 InetAddress ip = InetAddress.getByName("192.168.1.1");
 Socket s = new Socket(ip, 8899);
 PrintStream ps = new PrintStream(s.getOutputStream());
 BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 String str = null;
 while(null != (str=br.readLine()))
 {
 ps.println(str);
 }
 }
}
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class Server {
 public static void main(String[] args) throws Exception
 {
 ServerSocket server = new ServerSocket(8899);
  Socket  s = server.accept();
  System.out.println("welcome to my Server");
  InputStream is = s.getInputStream();
  OutputStream os = s.getOutputStream();
  BufferedReader br = new BufferedReader(new InputStreamReader(is));
  String str=null;
  while(null != (str=br.readLine()))
  {
  System.out.println("Client应答："+str);
  }
 }
}

class GetPort{ 共享资源类

	（_________） int port;		共享的端口

	

	public GetPort(int port){	构造方法

		this.port = port;

	}

		

	（_________） int getPort(){	获得端口累加号

		return port++;

	}

}



class ScanThread extends （_________）{		扫描端口线程类

	String host;		目标主机

	GetPort port;		共享的端口资源

	Thread t;		主线程

	String name;		子线程名称

	public ScanThread(String host, GetPort port, String name, Thread t){	构造方法

		this.host 	= host;

		this.t 		= t;

		this.port 	= port;

		this.name 	= name;

	}

	

	（_________）(){		线程运行方法

		try{

			Socket s = new （_________）();

			RandomAccessFile raf;

			int p = 0;

			while((p = port.getPort())<（_________）){

				SocketAddress inet = new （_________）(host, p);

				s.（_________）(inet, 5000);

				if(s.（_________）()){

					raf = new RandomAccessFile("record.dat", "rw");

					raf.（_________）(raf.length());

					raf.（_________）(p);

					raf.close();

				}

			}	

			s.close();

		}（_________）(Exception e){

			e.printStackTrace();

		}（_________）{

			try{

				t.（_________）();

			}catch(Exception e){

				e.printStackTrace();

			}

		}

	}

}



class mainThread{		主类

	public static void main(String [] args){	主方法

		int 	flag = 0;			线程累计数

		String 	host;				目标主机

		Thread 	t = Thread.currentThread();	获得主线程

		GetPort p = new GetPort(0);		共享的端口累加资源



		try{

			host = (new （_________）(System.in)).next();

			for(int i=0; i<10; i++){

				（new ScanThread(host, p, "Thread-"+i, t)).（_________）;

			

			while(flag < 10){	采用唤醒等待的方法，保证子线程都正常结束

	        		synchronized(t){

					flag++;	

					t.（_________）();

				}

			}

		}catch(Exception e){

			e.printStackTrace();

		}	

	}

}



（10.0分）

private

synchronized

Thread

public void run

Socket

65535

InetSocketAddress

connect

isReachable

seek

writeUTF

catch 

finally

close

Scanner

start

第一空： 
java.nio.

new SAXReader()

read

getRootElement()

Element

raf.getChannel()



allocate

isEmpty



Element

clear

getBytes

flip

hasRemaining

3
import java.io.IOException;

import java.net.InetSocketAddress;

import java.nio.ByteBuffer;

import java.nio.channels.Channel;

import java.nio.channels.SelectionKey;

import java.nio.channels.Selector;

import java.nio.channels.ServerSocketChannel;

import java.nio.channels.SocketChannel;



public class ChatRoomServer {

    private Selector selector = null;	事件选择器

    static final int port = 9999;

    

    public void init() throws IOException

    {

        selector = Selector.（_________）();	获得selector对象

        ServerSocketChannel server = ServerSocketChannel.（_________）(); 获得channel对象

        server.（_________）(new InetSocketAddress(port));

        server.configureBlocking（_________）;	

        server.register(selector, （_________）);	注册监听事件

        

        System.out.println("Server is listening now...");

        

        while(true) {

            int readyChannels = selector.select();

            if(readyChannels == 0) continue; 

            Set selectedKeys = selector.（_________）();  	获得事件列表

            Iterator keyIterator = selectedKeys.iterator();

            while(keyIterator.hasNext()) {

                 SelectionKey sk = (SelectionKey) keyIterator.next();

                 keyIterator.（_________）();		移除已处理过的事件

                 dealWithSelectionKey(server,sk);

            }

        }

    }

    

    public void dealWithSelectionKey(ServerSocketChannel server,SelectionKey sk) throws 



IOException {

        if(sk.isAcceptable())	有连接请求

        {

            SocketChannel sc = server.（_________）();

            sc.（_________）(false);

            sc.register(selector, SelectionKey.OP_READ);

            sk.interestOps(SelectionKey.OP_ACCEPT);

        }

        if(sk.isReadable())	有数据到达

        {

            SocketChannel sc = (SocketChannel)sk.（_________）(); 

            ByteBuffer buff = ByteBuffer.（_________）(1024);

            StringBuilder content = new StringBuilder();

            try

            {

                while(sc.read(buff) > 0)

                {

                    buff.（_________）();

                    content.append(buff);

                    

                }

                System.out.println(content);

                sk.（_________）(SelectionKey.OP_READ);		追加关注事件

            }

            catch (IOException io)

            {

                sk.cancel();

                if(sk.channel() != null)

                {

                    sk.channel().close();

                }

            }

        }

    }

    

    public static void main(String[] args) throws IOException 

    {

        new ChatRoomServer().init();

    }

}



（10.0分）
我的答案:

第一空： 
open

open

bind

false

selectionKey.OP ACCEPT

selectedKeys

remove

accept

configureBlocking

channel

allocate

flip

interestOps