实验四、五的代码.txt

一个防止黑客入侵程序

试验四：
import java.io.*;
class student implements Serializable{
String id;
String name;
String age;
}
public class Class1
{
	
public static void main (String[] args)throws IOException,ClassNotFoundException
	{
		student s[]=new student[5];
		int i;
		for(i=0;i<s.length;i++)
			s[i]=new student();
		InputStreamReader ir;
		BufferedReader in;
		ir=new InputStreamReader(System.in);
		in=new BufferedReader(ir);
		FileOutputStream out1=new FileOutputStream("student.txt");
		OutputStreamWriter out2=new OutputStreamWriter(out1);
		BufferedWriter out=new BufferedWriter(out2);
		FileOutputStream fo=new FileOutputStream("student.dat");
		ObjectOutputStream so=new ObjectOutputStream(fo);
		for(i=0;i<s.length;i++)
		{s[i].id=in.readLine();
		s[i].name=in.readLine();
		s[i].age=in.readLine();
		out.write(s[i].id+" ");
		out.write(s[i].name+" ");
		out.write(s[i].age+" ");
		out.newLine();
		so.writeObject(s[i]);
		}
		out.close();
		so.close();
		FileInputStream fi=new FileInputStream("student.dat");
		ObjectInputStream si=new ObjectInputStream(fi);
		student stu1;
		for(i=0;i<s.length;i++){
			stu1=(student)si.readObject();
		System.out.println("student no:"+i);
		System.out.println("id:"+stu1.id);
		System.out.println("name:"+stu1.name);
		System.out.println("age:"+stu1.age);}
		si.close();
		while((i=System.in.read())!=49){};
			
	}
}
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实验五：
import java.awt.*;
import java.awt.event.*;

public class Class1 implements MouseMotionListener,MouseListener,WindowListener
{         private Frame f;
		  private TextField tf;
		  
		  
	/**
	 * The main entry point for the application. 
	 *
	 * @param args Array of parameters passed to the application
	 * via the command line.
	 */
	public static void main (String[] args)
	{
		Class1 two=new Class1();
		two.go();// TODO: Add initialization code here
	}
	public void go()
	{       f=new Frame("Two listeners example");
		    f.add(new Label("Click and Drag the mouse"),"North");
			tf=new TextField(30);
			f.add(tf,"South");
			f.addMouseMotionListener(this);
			f.addMouseListener(this);
			f.addWindowListener(this);
			f.setSize(300,200);
			f.setVisible(true);
	}
	public void mouseDragged(MouseEvent e)
	{ String s="Mouse dragging:X"+e.getX()+"Y="+e.getY();
	  tf.setText(s);
		
	}
	public void mouseMoved(MouseEvent e){
	 String s="The moving entered";
	 tf.setText(s);
	 }
	public void mouseClicked(MouseEvent e){
	String s="The click entered";
	tf.setText(s);
	
	}
	public void mouseEntered(MouseEvent e){
	      String s="The mouse entered";
	        tf.setText(s);}
	public void mouseExited(MouseEvent e){
	       String s="The mouse has left the building";
	       tf.setText(s); }
	public void mousePressed(MouseEvent e){}
	public void mouseReleased(MouseEvent e){}
	public void windowClosing(WindowEvent e){
	        System.exit(1);}
	public void windowOpened(WindowEvent e){}
	public void windowIconified(WindowEvent e){
	 System.out.println("xsgvcbvchnv!");
	}
	public void windowDeiconified(WindowEvent e){
		 System.out.println("123456789!");
	    }
	public void windowClosed(WindowEvent e){}
	public void windowActivated(WindowEvent e){}
	public void windowDeactivated(WindowEvent e){}
	
}
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对话框：
import java.awt.*;
import java.awt.event.*;
class Handler implements ActionListener {
	Dialog d;
	public void actionPerformed(ActionEvent e){
		if (e.getActionCommand()=="打开对话框")
		  d.setVisible(true);
		else
		  d.setVisible(false);
		
	}
}
public class Class1
{
	public static void main (String[] args)
	{
		Frame f=new Frame();
		Handler h=new Handler();
		Dialog d=new Dialog(f,"Dialog",false);
		d.add("Center",new Label("Hello,I am a Dialog!"));
		d.setSize(100,100);
    	//d.pack();
		//d.setVisible(true);
		Button b1=new Button("打开对话框");
		Button b2=new Button("关闭对话框");
		f.add("North",b1);
		d.add("North",b2);
		h.d=d;
		b1.addActionListener(h);
		b2.addActionListener(h);
		f.setSize(200,100);
		f.show();
        
	
	}
}
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菜单：
import java.awt.*;
import java.awt.event.*;
//菜单无法进行布局管理,只能出现在窗口的固定位置
//在菜单中真正产生动作的是菜单项
public class Class1
{
	public static void main (String[] args)
	{
		Frame f=new Frame("菜单条");
		MenuBar mb=new MenuBar();//菜单条无法单独显示出来,用于管理菜单
		Menu m1=new Menu("文件");
		Menu m2=new Menu("编辑");
		Menu m3=new Menu("帮助");
		MenuItem mi1=new MenuItem("打开文件");
		CheckboxMenuItem mi2=new CheckboxMenuItem("CheckItem");
		m1.add(mi1);//在m1菜单上添加mi1菜单项
		m1.add(mi2);
		mb.add(m1);//将菜单添加到菜单条上
		mb.add(m2);
		mb.add(m3);
		Handler handler=new Handler();
		handler.f=f;
		mi1.addActionListener(handler);
		Handler1 handler1=new Handler1();
		mi2.addItemListener(handler1);
		f.setMenuBar(mb);//注意并没有使用f.add方法
		f.setSize(180,180);
		f.show();
	
	}
}
class Handler implements ActionListener {
	Frame f;
	public void actionPerformed(ActionEvent e){
	    FileDialog fd=new FileDialog(f,"Dialog");
		fd.setVisible(true);
	}
}	
 class Handler1 implements ItemListener{
	 public void itemStateChanged(ItemEvent e){
		 System.out.println(e.getItem()+" "+e.getStateChange() ); 
	 }
 }
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期中考试：
import java.awt.*;
import java.awt.event.*;
import java.io.*;
public class Class1
{
	public static void main (String[] args)
	{
		Frame f=new Frame("菜单条");
		Student student[]=new Student[10];
		int i;
		for (i=0;i<student.length;i++)
		{ 
		  student[i]=new Student();
		  student[i].name=new String();
		  student[i].sex=new String();
		  student[i].no=new String();
		} 
		MenuBar mb=new MenuBar();//菜单条无法单独显示出来,用于管理菜单
		Menu m1=new Menu("文件");
		Menu m2=new Menu("输入");
		MenuItem mi1=new MenuItem("打开文件");
		MenuItem mi2=new MenuItem("保存数据");
		MenuItem mi3=new MenuItem("数据输入");
		m1.add(mi1);//在m1菜单上添加mi1菜单项
		m1.add(mi2);
		m2.add(mi3);
		mb.add(m1);//将菜单添加到菜单条上
		mb.add(m2);
		Handler handler=new Handler();
		handler.f=f;
		handler.stu=student;
		mi1.addActionListener(handler);
		mi2.addActionListener(handler);
		mi3.addActionListener(handler);
		f.setMenuBar(mb);//注意并没有使用f.add方法
		f.setSize(280,280);
		f.show();
	
	}
}
class Handler implements ActionListener {
	Frame f;
	Student stu[];
	public void actionPerformed(ActionEvent e){
	  if (e.getActionCommand()=="打开文件")
	  {
	    FileDialog fd=new FileDialog(f,"Dialog");
	    fd.setVisible(true);
		System.out.println(stu[0].name+" " +stu[0].sex);
	  }
	  else if (e.getActionCommand()=="保存数据")
	  {
		  
	    FileDialog fd=new FileDialog(f,"Dialog");
	    fd.setVisible(true);
		try
		{
		 FileOutputStream out =new FileOutputStream(fd.getFile()) ;
		 OutputStreamWriter out1=new OutputStreamWriter(out);
		 int i;
		 for (i=0;i<stu.length-1;i++)
		 {
		   out1.write(stu[i].name,0,stu[i].name.length());
		   out1.write(stu[i].sex,0,stu[i].sex.length());
		   out1.write(stu[i].no,0,stu[i].no.length());
		   out1.write('\r');
		   out1.write('\n');
		   System.out.println(stu[i].name+stu[i].sex+stu[i].no);
		   
		 }
		 out1.close();
		 out.close();
		}
		catch(IOException ioe)
		{
			System.out.println(ioe);
		}			
	  }
	  else if (e.getActionCommand()=="数据输入")
	  {
		  Dialog d=new Dialog(f,"数据输入",true);
		  TextField tf1,tf2,tf3;
		  Button b1,b2,b3,b4;
		  d.setLayout(new GridLayout(5,2));
		  d.add(new Label("姓名"));
		  d.add(tf1=new TextField(8));
		  d.add(new Label("性别"));
		  d.add(tf2=new TextField("男",1));
		  d.add(new Label("学号"));
		  d.add(tf3=new TextField(8));
		  d.add(b1=new Button("前一条"));
		  d.add(b2=new Button("后一条"));
		  d.add(b3=new Button("确定"));
		  d.add(b4=new Button("取消"));
		  Handler1 handler1=new Handler1();
		  b1.addActionListener(handler1);
		  b2.addActionListener(handler1);
		  b3.addActionListener(handler1);
		  b4.addActionListener(handler1);
		  handler1.d=d;
		  handler1.stu=stu;
		  handler1.num=0;
		  handler1.max=0;
		  handler1.tf1=tf1;
		  handler1.tf2=tf2;
		  handler1.tf3=tf3;
		  d.pack();
		  d.setVisible(true);
	  }
	}
}
class Handler1 implements ActionListener {
	Dialog d;
    TextField tf1,tf2,tf3;
	Student stu[];
	static int num,max;
	public void actionPerformed(ActionEvent e){
		if (e.getActionCommand()=="后一条" && num < stu.length-1 )
		{
			stu[num].name=tf1.getText();
			stu[num].sex=tf2.getText();
			stu[num].no=tf3.getText();
			if (num >=max)
			{
			 tf1.setText("");
			 tf2.setText("男");
		     tf3.setText("");
			 num+=1;
			 max+=1;
			} 
			else
			{
			 num+=1;
			 tf1.setText(stu[num].name);
			 tf2.setText(stu[num].sex);
		     tf3.setText(stu[num].no);
			}
		}
	  else if (e.getActionCommand()=="确定")
		{
			stu[num].name=tf1.getText();
			stu[num].sex=tf2.getText();
			stu[num].no=tf3.getText();
			d.setVisible(false);
		}
	}
}
class Student{
	String name;
	String sex;
	String no;
}
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P206:
例13-9：
import java.awt.*;
import java.applet.*;
import java.awt.image.*;
import java.awt.event.*;
/**
 * This class reads PARAM tags from its HTML host page and sets
 * the color and label properties of the applet. Program execution
 * begins with the init() method. 
 */
public class Applet1 extends Applet implements MouseListener 
{
	Image img;
	Image newImg;
	int x1,y1,w,h,count=1;
	
	public void init()
	{
		img=getImage(getDocumentBase(),"bg.jpg");
		newImg=img;
		this.addMouseListener(this);
	}	

	public void paint(Graphics g){
	    int w=newImg.getWidth(this);//this 为图像观测者
		int h=newImg.getHeight(this);
		Dimension d=getSize();
		if(w>d.width ) w=d.width;
		if(h>d.height) h=d.height ;
		
		//g.drawImage(newImg,0,0,this);
		g.drawImage(newImg,(d.width-w)/2,(d.height-h)/2,this);//居中显示,但有误差
	}
	
	public void mouseClicked(MouseEvent e){}
	
	public void mouseEntered(MouseEvent e){
	}

	public void mouseExited(MouseEvent e){
	}
	
	public void mousePressed(MouseEvent e){
		int x,y;
		Graphics g=getGraphics();
		x=e.getX();
		y=e.getY();
		if (count==1){
			x1=x;y1=y;count=2;//得到要截取区域的左上角坐标
			g.drawLine(x-5,y,x+5,y);
			g.drawLine(x,y-5,x,y+5);
		}else if(count==2){
			count=3;
			if(x1>x)w=x1-x;//得到要截取区域的宽度与高度
			  else w=x-x1;
			if(y1>y) h=y1-y;
			   else h=y-y1;
			newImg=crop();
			repaint();
		}else{
			count=1;
			newImg=img;
			repaint();
		}
		g.drawString("x1="+x,10,10);
			
	}
	
	public void mouseReleased(MouseEvent e){
		Graphics g=getGraphics();
		g.drawString("x2="+e.getX(),28,28);
	}

	Image crop(){
		Dimension d=getSize();
		ImageFilter filter=new CropImageFilter(x1,y1,w,h);//截取时是按照图像的坐标
		ImageProducer producer =new FilteredImageSource(img.getSource(),filter);
		return createImage(producer);
	//	return createImage(img.getSource());
	}
	
}