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) 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
(二)结对编程:1人负责客户端,一人负责服务器
- 注意责任归宿,要会通过测试证明自己没有问题
- 基于Java Socket实现客户端/服务器功能,传输方式用TCP
- 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
- 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
- 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
- 注意责任归宿,要会通过测试证明自己没有问题
- 基于Java Socket实现客户端/服务器功能,传输方式用TCP
- 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
- 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
- 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
- 注意责任归宿,要会通过测试证明自己没有问题
- 基于Java Socket实现客户端/服务器功能,传输方式用TCP
- 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
- 客户端和服务器用DH算法进行3DES或AES算法的密钥交换
- 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
- 客户端显示服务器发送过来的结果
- 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
- 注意责任归宿,要会通过测试证明自己没有问题
- 基于Java Socket实现客户端/服务器功能,传输方式用TCP
- 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
- 客户端和服务器用DH算法进行3DES或AES算法的密钥交换
- 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
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% |