实验五网络编程

实验五网络编程

课程：Java程序设计

班级：1652

姓名：孔月

学号：20165208

指导教师：娄嘉鹏

实验日期：2018.5.28

实验名称：网络编程

实验内容、步骤与体会

目录：

• （一）
• （二）
• （三）
• （四）
• （五）

（一） 结对实现中缀表达式转后缀表达式的功能 MyBC.java, 结对实现从上面功能中获取的表达式中实现后缀表达式求值的功能,调用MyDC.java

import java.util.StringTokenizer;
import java.util.Stack;

public class MyDC {
    private final char ADD = '+';
    private final char SUBTRACT = '-';
    private final char MULTIPLY = '*';
    private final char DIVIDE = '/';
    private Stack<Integer> stack;

    public MyDC() {
        stack = new Stack<Integer>();
    }

    public int evaluate(String expr) {
        int op1, op2, result = 0;
        String token;
        StringTokenizer tokenizer = new StringTokenizer(expr);

        while (tokenizer.hasMoreTokens()) {
            token = tokenizer.nextToken();

            if (isOperator(token)) {
                op2 = (stack.pop()).intValue();
                op1 = (stack.pop()).intValue();
                result = evalSingleOp(token.charAt(0), op1, op2);
                stack.push(new Integer(result));
            } else
                stack.push(new Integer(Integer.parseInt(token)));
        }

        return result;
    }

    private boolean isOperator(String token) {
        return (token.equals("+") || token.equals("-") ||
                token.equals("*") || token.equals("/"));
    }

    private int evalSingleOp(char operation, int op1, int op2) {
        int result = 0;

        switch (operation) {
            case ADD:
                result = op1 + op2;
                break;
            case SUBTRACT:
                result = op1 - op2;
                break;
            case MULTIPLY:
                result = op1 * op2;
                break;
            case DIVIDE:
                result = op1 / op2;
        }

        return result;
    }
}

import java.io.IOException;
import java.util.Scanner;
public class MyBC {
    private Stack theStack;
    private String input;
    private String output = "";
    public MyBC(String in) {
        input = in;
        int stackSize = input.length();
        theStack = new Stack(stackSize);
    }
    public String doTrans() {
        for (int j = 0; j < input.length(); j++) {
            char ch = input.charAt(j);
            switch (ch) {
                case '+':
                case '-':
                    gotOper(ch, 1);
                    break;
                case '*':
                case '/':
                    gotOper(ch, 2);
                    break;
                case '(':
                    theStack.push(ch);
                    break;
                case ')':
                    gotParen(ch);
                    break;
                default:
                    output = output + ch;
                    break;
            }
        }
        while (!theStack.isEmpty()) {
            output = output + theStack.pop();
        }
        System.out.println(output);
        return output;
    }
    public void gotOper(char opThis, int prec1) {
        while (!theStack.isEmpty()) {
            char opTop = theStack.pop();
            if (opTop == '(') {
                theStack.push(opTop);
                break;
            }
            else {
                int prec2;
                if (opTop == '+' || opTop == '-')
                    prec2 = 1;
                else
                    prec2 = 2;
                if (prec2 < prec1) {
                    theStack.push(opTop);
                    break;
                }
                else
                    output = output + opTop;
            }
        }
        theStack.push(opThis);
    }
    public void gotParen(char ch){
        while (!theStack.isEmpty()) {
            char chx = theStack.pop();
            if (chx == '(')
                break;
            else
                output = output + chx;
        }
    }
    public static void main(String[] args) throws IOException {
        Scanner in = new Scanner(System.in);
        String input = in.nextLine();
        System.out.println(input);
        String output;
        MyBC theTrans = new MyBC(input);
        output = theTrans.doTrans();
    }
    class Stack {
        private int maxSize;
        private char[] stackArray;
        private int top;
        public Stack(int max) {
            maxSize = max;
            stackArray = new char[maxSize];
            top = -1;
        }
        public void push(char j) {
            stackArray[++top] = j;
        }
        public char pop() {
            return stackArray[top--];
        }
        public char peek() {
            return stackArray[top];
        }
        public boolean isEmpty() {
            return (top == -1);
        }
    }
}

实验效果如下图

返回目录

（二）结对编程：1人负责客户端，一人负责服务器 0. 注意责任归宿，要会通过测试证明自己没有问题 1. 基于Java Socket实现客户端/服务器功能，传输方式用TCP 2. 客户端让用户输入中缀表达式，然后把中缀表达式调用MyBC.java的功能转化为后缀表达式，把后缀表达式通过网络发送给服务器 3. 服务器接收到后缀表达式，调用MyDC.java的功能计算后缀表达式的值，把结果发送给客户端 4. 客户端显示服务器发送过来的结果

import java.io.*;
import java.net.*;
import static java.lang.Integer.*;

public class Server {
    public static void main(String[] args) {
        ServerSocket serverSocket = null;
        Socket socket = null;
        OutputStream os = null;
        InputStream is = null;
        int port = 8087;
        try {
            serverSocket = new ServerSocket(port);
            System.out.println("建立连接成功！");
            socket = serverSocket.accept();
            System.out.println("获得连接成功！");
            is = socket.getInputStream();
            byte[] b = new byte[1024];
            int n = is.read(b);
            System.out.println("接收数据成功！");
            String message=new String(b,0,n);
            System.out.println("来自客户端的数据内容为：" + message);
            String output;
            MyBC theTrans = new MyBC(message);
            output = theTrans.doTrans();
            os = socket.getOutputStream();
            os.write(output.getBytes());
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            try{
                os.close();
                is.close();
                socket.close();
                serverSocket.close();
            }catch(Exception e){}
        }
    }
}

import java.io.*;
import java.net.*;
public class Client {
    public static void main(String[] args) {
        Socket socket = null;
        InputStream is = null;
        OutputStream os = null;
        String serverIP = "172.16.252.50";
        int port = 8087;
        System.out.println("输入中缀表达式：20-16/4+52-11*2");
        String output;
        MyBC theTrans = new MyBC("20-16/4+52-11*2");
        output = theTrans.doTrans();
        try {
            socket = new Socket(serverIP, port);
            System.out.println("建立连接成功！");
            os = socket.getOutputStream();
            os.write(output.getBytes());
            System.out.println("发送数据成功！");
            is = socket.getInputStream();
            byte[] b = new byte[1024];
            int n = is.read(b);
            System.out.println("接收数据成功！");
            System.out.println("来自服务器的数据内容为：" + new String(b, 0, n));
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
                os.close();
                socket.close();
            } catch (Exception e2) {
            }
        }
    }
}

效果如图

（三）加密结对编程：1人负责客户端，一人负责服务器 0. 注意责任归宿，要会通过测试证明自己没有问题 1. 基于Java Socket实现客户端/服务器功能，传输方式用TCP 2. 客户端让用户输入中缀表达式，然后把中缀表达式调用MyBC.java的功能转化为后缀表达式，把后缀表达式用3DES或AES算法加密后通过网络把密文发送给服务器 3. 服务器接收到后缀表达式表达式后，进行解密（和客户端协商密钥，可以用数组保存），然后调用MyDC.java的功能计算后缀表达式的值，把结果发送给客户端 4. 客户端显示服务器发送过来的结果

import java.io.*;

import java.net.Socket;

public class ClientSend {
    public static void main(String[] args) {
        Socket s = null;
        try {
            s = new Socket("192.168.56.1", 12345);
        }catch (IOException e) {
            System.out.println("未连接到服务器");
        }
        try {
            DataInputStream input = new DataInputStream(s.getInputStream());
            System.out.print("请输入: \t");
            String str = new BufferedReader(new InputStreamReader(System.in)).readLine();
            MyBC turner = new MyBC();
            String str1 = turner.turn(str);
            int length = 0, i = 0;
            while (str1.charAt(i) != '\0') {
                length++;
                i++;
            }
            String str2 = str1.substring(1, length - 1);
            SEnc senc = new SEnc(str2);//指定后缀表达式为明文字符
            senc.encrypt();//加密
        }catch(Exception e) {
            System.out.println("客户端异常:" + e.getMessage());
        }
        File sendfile = new File("SEnc.dat");
        File sendfile1 = new File("Keykb1.dat");
        FileInputStream fis = null;
        FileInputStream fis1 = null;
        byte[] buffer = new byte[4096 * 5];
        byte[] buffer1 = new byte[4096 * 5];
        OutputStream os;
        if(!sendfile.exists() || !sendfile1.exists()){
            System.out.println("客户端：要发送的文件不存在");
            return;
        }
        try {
            fis = new FileInputStream(sendfile);
            fis1 = new FileInputStream(sendfile1);
        } catch (FileNotFoundException e1) {
            e1.printStackTrace();
        }
        try {
            PrintStream ps = new PrintStream(s.getOutputStream());
            ps.println("111/#" + sendfile.getName() + "/#" + fis.available());
            ps.flush();
        } catch (IOException e) {
            System.out.println("服务器连接中断");
        }
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e1) {
            e1.printStackTrace();
        }
        try {
            os = s.getOutputStream();
            int size = 0;
            while((size = fis.read(buffer)) != -1){
                System.out.println("客户端发送数据包，大小为" + size);
                os.write(buffer, 0, size);
                os.flush();
            }
        } catch (FileNotFoundException e) {
            System.out.println("客户端读取文件出错");
        } catch (IOException e) {
            System.out.println("客户端输出文件出错");
        }finally{
            try {
                if(fis != null)
                    fis.close();
            } catch (IOException e) {
                System.out.println("客户端文件关闭出错");
            }
        }
        try {
            PrintStream ps1 = new PrintStream(s.getOutputStream());
            ps1.println("111/#" + sendfile1.getName() + "/#" + fis1.available());
            ps1.flush();
        } catch (IOException e) {
            System.out.println("服务器连接中断");
        }
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e1) {
            e1.printStackTrace();
        }
        try {
            os = s.getOutputStream();
            int size = 0;
            while((size = fis1.read(buffer1)) != -1){
                System.out.println("客户端发送数据包，大小为" + size);
                os.write(buffer1, 0, size);
                os.flush();
            }
        } catch (FileNotFoundException e) {
            System.out.println("客户端读取文件出错");
        } catch (IOException e) {
            System.out.println("客户端输出文件出错");
        }finally{
            try {
                if(fis1 != null)
                    fis1.close();
            } catch (IOException e) {
                System.out.println("客户端文件关闭出错");
            }
        }
        try{
            DataInputStream input = new DataInputStream(s.getInputStream());
            String ret = input.readUTF();
            System.out.println("服务器端返回过来的是: " + ret);
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            if (s == null) {
                try {
                    s.close();
                } catch (IOException e) {
                    System.out.println("客户端 finally 异常:" + e.getMessage());
                }
            }
        }
    }
}

最终运行效果如图

（四）密钥分发结对编程：1人负责客户端，一人负责服务器

0. 注意责任归宿，要会通过测试证明自己没有问题
1. 基于Java Socket实现客户端/服务器功能，传输方式用TCP
2. 客户端让用户输入中缀表达式，然后把中缀表达式调用MyBC.java的功能转化为后缀表达式，把后缀表达式用3DES或AES算法加密通过网络把密文发送给服务器
3. 客户端和服务器用DH算法进行3DES或AES算法的密钥交换
4. 服务器接收到后缀表达式表达式后，进行解密，然后调用MyDC.java的功能计算后缀表达式的值，把结果发送给客户端
5. 客户端显示服务器发送过来的结果
6. 上传测试结果截图和码云链接
   测试代码

import java.io.*;
import java.math.*;
import java.security.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.crypto.interfaces.*;

public class Key_DH{
       //三个静态变量的定义从
// C:\j2sdk-1_4_0-doc\docs\guide\security\jce\JCERefGuide.html
// 拷贝而来
// The 1024 bit Diffie-Hellman modulus values used by SKIP
    private static final byte skip1024ModulusBytes[] = {
        (byte)0xF4, (byte)0x88, (byte)0xFD, (byte)0x58,
        (byte)0x4E, (byte)0x49, (byte)0xDB, (byte)0xCD,
        (byte)0x20, (byte)0xB4, (byte)0x9D, (byte)0xE4,
        (byte)0x91, (byte)0x07, (byte)0x36, (byte)0x6B,
        (byte)0x33, (byte)0x6C, (byte)0x38, (byte)0x0D,
        (byte)0x45, (byte)0x1D, (byte)0x0F, (byte)0x7C,
        (byte)0x88, (byte)0xB3, (byte)0x1C, (byte)0x7C,
        (byte)0x5B, (byte)0x2D, (byte)0x8E, (byte)0xF6,
        (byte)0xF3, (byte)0xC9, (byte)0x23, (byte)0xC0,
        (byte)0x43, (byte)0xF0, (byte)0xA5, (byte)0x5B,
        (byte)0x18, (byte)0x8D, (byte)0x8E, (byte)0xBB,
        (byte)0x55, (byte)0x8C, (byte)0xB8, (byte)0x5D,
        (byte)0x38, (byte)0xD3, (byte)0x34, (byte)0xFD,
        (byte)0x7C, (byte)0x17, (byte)0x57, (byte)0x43,
        (byte)0xA3, (byte)0x1D, (byte)0x18, (byte)0x6C,
        (byte)0xDE, (byte)0x33, (byte)0x21, (byte)0x2C,
        (byte)0xB5, (byte)0x2A, (byte)0xFF, (byte)0x3C,
        (byte)0xE1, (byte)0xB1, (byte)0x29, (byte)0x40,
        (byte)0x18, (byte)0x11, (byte)0x8D, (byte)0x7C,
        (byte)0x84, (byte)0xA7, (byte)0x0A, (byte)0x72,
        (byte)0xD6, (byte)0x86, (byte)0xC4, (byte)0x03,
        (byte)0x19, (byte)0xC8, (byte)0x07, (byte)0x29,
        (byte)0x7A, (byte)0xCA, (byte)0x95, (byte)0x0C,
        (byte)0xD9, (byte)0x96, (byte)0x9F, (byte)0xAB,
        (byte)0xD0, (byte)0x0A, (byte)0x50, (byte)0x9B,
        (byte)0x02, (byte)0x46, (byte)0xD3, (byte)0x08,
        (byte)0x3D, (byte)0x66, (byte)0xA4, (byte)0x5D,
        (byte)0x41, (byte)0x9F, (byte)0x9C, (byte)0x7C,
        (byte)0xBD, (byte)0x89, (byte)0x4B, (byte)0x22,
        (byte)0x19, (byte)0x26, (byte)0xBA, (byte)0xAB,
        (byte)0xA2, (byte)0x5E, (byte)0xC3, (byte)0x55,
        (byte)0xE9, (byte)0x2F, (byte)0x78, (byte)0xC7
    };
    // The SKIP 1024 bit modulus
    private static final BigInteger skip1024Modulus
              = new BigInteger(1, skip1024ModulusBytes);
    // The base used with the SKIP 1024 bit modulus
    private static final BigInteger skip1024Base = BigInteger.valueOf(2);
public static void main(String args[ ]) throws Exception{
    DHParameterSpec DHP=
new DHParameterSpec(skip1024Modulus,skip1024Base);

     KeyPairGenerator kpg= KeyPairGenerator.getInstance("DH");
     kpg.initialize(DHP);
     KeyPair kp=kpg.genKeyPair();

     PublicKey pbk=kp.getPublic();
     PrivateKey prk=kp.getPrivate();
     // 保存公钥
     FileOutputStream  f1=new FileOutputStream(args[0]);
     ObjectOutputStream b1=new  ObjectOutputStream(f1);
     b1.writeObject(pbk);
     // 保存私钥
     FileOutputStream  f2=new FileOutputStream(args[1]);
     ObjectOutputStream b2=new  ObjectOutputStream(f2);
     b2.writeObject(prk);
   }      
} 

测试如下图

（五）使用StarUML对实验中的代码进行建模

完整性校验结对编程：1人负责客户端，一人负责服务器
0. 注意责任归宿，要会通过测试证明自己没有问题

1. 基于Java Socket实现客户端/服务器功能，传输方式用TCP
2. 客户端让用户输入中缀表达式，然后把中缀表达式调用MyBC.java的功能转化为后缀表达式，把后缀表达式用3DES或AES算法加密通过网络把密文和明文的MD5値发送给服务器
3. 客户端和服务器用DH算法进行3DES或AES算法的密钥交换
4. 服务器接收到后缀表达式表达式后，进行解密，解密后计算明文的MD5值，和客户端传来的MD5进行比较，一致则调用MyDC.java的功能计算后缀表达式的值，把结果发送给客户端
5. 客户端显示服务器发送过来的结果

String x= exp;
    MessageDigest m=MessageDigest.getInstance("MD5");
    m.update(x.getBytes("UTF8"));
    byte s[ ]=m.digest( );
    String res="";
    for (int j=0; j<s.length; j++){
        res +=Integer.toHexString((0x000000ff & s[j]) |0xffffff00).substring(6);
    }
    System.out.printf("md5Check:" + md5.equals(res));
    
    ```

String x= str2;
MessageDigest m=MessageDigest.getInstance("MD5");
m.update(x.getBytes("UTF8"));
byte s[ ]=m.digest( );
String result="";
for (int j=0; j<s.length; j++){
result+=Integer.toHexString((0x000000ff & s[j]) |0xffffff00).substring(6);
}
```

问题总结与体会

• 问题1：有关客户端的问题刚开始完全没思路
• 解决方案：重新看了一遍13章

步骤	耗时	百分比
需求分析	25 min	8.3%
设计	70 min	23.3%
代码实现	120 min	40%
测试	40 min	13.3%
分析总结	45 min	15%