一个简单的java编程

代码如下，分两部分来捕捉异常

public class demo

{

public static void main(String args[])

{

int numbers[5];

for(int i=0;i<5;i++)

{

String str;

try // one

{

str=args[i];

}

catch(IndexOutOfBoundsException e)

{

Systemoutprintln("请你输入至少5个整数");

}

try //two

{

numbers[i]=IntegerparseInt(str);

}

catch(NumberFormatException e)

{

Systemoutprintln("请输入的全部都是数字串");

}

}

}

}

//问题：求一个长方形的周长和面积

/以面向过程的程序设计方式思考:

1确定长方形的周长和面积的算法；

2编写两个方法（函数）分别计算长方形的周长和面积;

3求周长的方法（函数）和求面积的方法（函数）需要两个参数，

分别是长方形的长和宽/

//面向过程的程序设计代码：

/classRectangle

{

static

float

perimeter(float

length,floatwidth)

{

return

2(length+width);

}

static

float

area(float

length,

float

width)

{

return

lengthwidth;

}

public

static

void

main(String[]

args)

{

Systemoutprintln("the

perimeter

is

="

+perimeter(3123f,4267f));

Systemoutprintln("the

area

is="

+area(3123f,4267f));//使用f来表示浮点

}

}/

/以面向对象的程序设计方式思考：

1一个长方形可以看成是一个长方形对象；

2一个长方形对象有两个状态（长和宽）和两个行为(求周长和面积)

3将所有长方形的共性抽取出来，设计一个长方形的类

4通过长方形对象的行为，就可以求出某个具体的长方形的周长和面积/

//面向对象的程序设计代码:

classRectangle

{

float

l,h;//有两个状态，即两个成员变量

float

perimeter()

{

return

2(l+h);

}

float

area()

{

return

lh;

}

public

static

void

main(String[]

args)

{

Rectangle

rect1=newRectangle();

Rectangle

rect2=newRectangle();

rect1l=1013f;

rect1h=574f;

rect2l=1221f;

rect2h=2413f;

Systemoutprintln("Theperimeter

is

="

+

rect1perimeter());

Systemoutprintln("The

area

is="

+

rect1area());

Systemoutprintln("Theperimeter

is

="

+

rect2perimeter());

Systemoutprintln("The

area

is="

+

rect2area());

}

/K:\Java\try\lesson3>javacRectanglejava

K:\Java\try\lesson3>java

Rectangle

The

perimeter

is

=3174

The

area

is

=581462

The

perimeter

is

=7268

The

area

is

=2946273

/

}

一个简单的java程序由java包（如：import javaawt）、类声明 、变量、构造方法（可缺省）、方法 这几部分构成。

java程序中至少要有一个类被声明为public。

import javaawtFlowLayout;

import javaawteventActionEvent;

import javaawteventActionListener;

import javaxswingJButton;

import javaxswingJFrame;

import javaxswingJLabel;

import javaxswingJOptionPane;

import javaxswingJPasswordField;

import javaxswingJTextField;

public class Login {

public static void main(String args[]) {

LoginFrm frame = new LoginFrm();

}

}

class LoginFrm extends JFrame implements ActionListener{

JLabel nameLabel=new JLabel("用户名：");

JLabel pwdLabel=new JLabel("密码：");

JTextField name=new JTextField(10);

JPasswordField password=new JPasswordField(10);

JButton butnSure=new JButton("确定");

JButton butnCancel=new JButton("取消");

public LoginFrm() {

super("登陆");

setBounds(500, 200, 280, 220);

setVisible(true);

setLayout(null);

nameLabelsetBounds(45, 20, 100, 25);

add(nameLabel);

add(name);

namesetBounds(105, 20, 110, 25);

add(pwdLabel);

pwdLabelsetBounds(45, 60, 100, 25);

add(password);

passwordsetBounds(105, 60, 110, 25);

add(butnSure);

butnSuresetBounds(45, 100, 80, 25);

add(butnCancel);

butnCancelsetBounds(135, 100, 80, 25);

butnSureaddActionListener(this);

butnCanceladdActionListener(this);

setDefaultCloseOperation(JFrameEXIT_ON_CLOSE);

validate();//刷新

}

public void actionPerformed(ActionEvent e) {

if (egetSource() ==butnSure){

Systemoutprintln("用户名："+namegetText());

Systemoutprintln("密码："+namegetText());

if("admin"equals(namegetText()trim())&&"123"equals(passwordgetText()trim())){

thisdispose();

new MainFrm("用户界面",namegetText()trim(),passwordgetText()trim());

}else {

JOptionPaneshowMessageDialog(this, "用户不存在");

}

}else if(egetSource()==butnCancel){

Systemexit(1);

}

}

class MainFrm extends JFrame{

private JLabel info;

public MainFrm(String s,String name,String password) {

super(s);

setBounds(400, 200, 500, 400);

setLayout(new FlowLayout());

info=new JLabel("登陆成功，用户名："+name+"，密码："+password);

add(info);

setVisible(true);

setDefaultCloseOperation(JFrameEXIT_ON_CLOSE);

validate();

}

}

}

是记事本的样式吗？就要这些要求吗？

下面这些代码的功能挺全的，可以参考一下，不用的可以删掉。

import javaio;

import javautilCalendar;

import javaawt;

import javaawtevent;

import javaxswing;

import javaxswingevent;

public class NoteBook extends JFrame implements ActionListener,ItemListener,WindowListener,MouseListener

{ Container c = thisgetContentPane();

JMenuBar jmb = new JMenuBar();

JColorChooser jcl = new JColorChooser();

JToolBar jToolBar = new JToolBar();

JButton jButton1 = new JButton();

JButton jButton2 = new JButton();

JButton jButton3 = new JButton();

JButton jButton4 = new JButton();

JMenu jm1 = new JMenu("文件(F)");

JMenu jm2 = new JMenu("编辑(E)");

JMenu jm4 = new JMenu("格式(O)");

JMenu jm5 = new JMenu("查看(V)");

JMenu jm3 = new JMenu("帮助(H)");

JMenuItem jmi1 = new JMenuItem("新建(N)");

JMenuItem jmi2 = new JMenuItem("打开(O)");

JMenuItem jmi3 = new JMenuItem("保存(S)");

JMenuItem jmi4 = new JMenuItem("退出(X)");

JMenu jmd4=new JMenu("颜色");

JMenu jmd0=new JMenu("字体");

JMenuItem aa=new JMenuItem("复制(C)");

JMenuItem bb=new JMenuItem("剪切(X)");

JMenuItem cc=new JMenuItem("粘贴(V)");

JCheckBoxMenuItem jcuti1 = new JCheckBoxMenuItem("粗体");

JCheckBoxMenuItem jxieti1 = new JCheckBoxMenuItem("斜体");

JMenuItem jmp1 = new JMenuItem("日期和时间");

JMenuItem jmp2 = new JMenuItem("背景颜色(H)");

JMenuItem jmi5 = new JMenuItem("删除内容(S)");

JMenuItem jmi7=new JMenuItem("关于自己");

JTextArea jta = new JTextArea(23,15);

JScrollPane jsp = new JScrollPane(jta);

JMenuItem jmdb1=new JMenuItem("**");//定义各种颜色

JMenuItem jmdb2=new JMenuItem("红色");

JMenuItem jmdb3=new JMenuItem("绿色");

JMenuItem jmdb4=new JMenuItem("蓝色");

JMenuItem jmdb5=new JMenuItem("黑色");

NoteBook()

{ thisaddWindowListener(this);

setBounds(200,200,200,200);

cadd(jmb,BorderLayoutNORTH);

validate();

setDefaultCloseOperation(JFrameEXIT_ON_CLOSE);

thissetResizable(false);

thissetTitle("记事本");

jmbadd(jm1);//文件

jm1setMnemonic('f');

jm1addActionListener(this);

jmbadd(jm2);//编辑

jm2setMnemonic('e');

jmbadd(jm4);//格式

jm4setMnemonic('o');

jm4addActionListener(this);

jmbadd(jm5);

jm5setMnemonic('v'); //查看

jmbadd(jm3);//帮助

jm3setMnemonic('h');

jmbsetLocation(0,0);

jm1add(jmi1);

jmi1addActionListener(this);//新建

jmi1setAccelerator(KeyStrokegetKeyStroke('N',EventCTRL_MASK,false));

jm1addSeparator();

jm1add(jmi2);

jmi2setAccelerator(KeyStrokegetKeyStroke('O',EventCTRL_MASK,false));

jmi2addActionListener(this);//打开

jm1addSeparator();

jm1add(jmi3);

jmi3setAccelerator(KeyStrokegetKeyStroke('S',EventCTRL_MASK,false));

jmi3addActionListener(this);//保存

jm1addSeparator();

jm1add(jmi4);

jmi1setMnemonic('n');

jmi2setMnemonic('o');

jmi3setMnemonic('s');

jmi4setMnemonic('x');

jmi4addActionListener(this);//退出

jm5add(jmi5); //删除

jm5addSeparator();

jmi5addActionListener(this);

jm4addSeparator();

jm4add(jmd4);

jm4add(jmd0);

jmd4add(jmdb1);

jmd4add(jmdb2);

jmd4add(jmdb3);

jmd4add(jmdb4);

jmd4add(jmdb5);

jmd4addActionListener(this); //添加监视器

jmdb1addActionListener(this);

jmdb2addActionListener(this);

jmdb3addActionListener(this);

jmdb4addActionListener(this);

jmdb5addActionListener(this);

jm5add(jmp1);

jm5addSeparator();

jm5add(jmp2);

jmp1addActionListener(this);//日期时间

jmp2addActionListener(this);//背景颜色

jm2add(aa);

jm2addSeparator();

jm2add(bb);

jm2addSeparator();

jm2add(cc);

jm2addSeparator();

jmd0add(jcuti1);

jmd0addSeparator();

jmd0add(jxieti1);

aasetMnemonic('C');

aasetAccelerator(KeyStrokegetKeyStroke(KeyEventVK_C,InputEventCTRL_MASK));

bbsetMnemonic('x');

bbsetAccelerator(KeyStrokegetKeyStroke(KeyEventVK_X,InputEventCTRL_MASK));

ccsetMnemonic('V');

ccsetAccelerator(KeyStrokegetKeyStroke(KeyEventVK_V,InputEventCTRL_MASK));

aaaddActionListener(this);//复制

bbaddActionListener(this);//剪切

ccaddActionListener(this);//粘贴

jmd4addActionListener(this);

jcuti1addItemListener(this);//粗体

jxieti1addItemListener(this);//斜体

jm3add(jmi7);

jmi7addActionListener(this);//关于自己

cadd(jToolBar,BorderLayoutCENTER); //工具条

jButton2setIcon(new ImageIcon("image\\newJPG"));//新建

jToolBaradd(jButton2);

jButton2setToolTipText("新建");

jButton2addActionListener(this);

jButton1setIcon(new ImageIcon("image\\openJPG"));//打开

jButton1setToolTipText("打开");

jToolBaradd(jButton1);

jButton1addActionListener(this);

jButton3setIcon(new ImageIcon("image\\saveJPG"));//保存

jToolBaradd(jButton3);

jButton3setToolTipText("保存");

jButton3addActionListener(this);

jButton4setIcon(new ImageIcon("image\\qqJPG"));

jButton4addActionListener(this); //退出

jToolBaradd(jButton4);

jButton4setToolTipText("退出");

cadd(jsp,BorderLayoutSOUTH);

thissetDefaultCloseOperation(JFrameDISPOSE_ON_CLOSE);

thissetSize(500,500);

thissetVisible(true);

jmdb1addActionListener(new ActionListener() //**

{ public void actionPerformed(ActionEvent e)

{ jtasetForeground(Coloryellow);

} } );

jmdb2addActionListener(new ActionListener() //红色

{ public void actionPerformed(ActionEvent e)

{ jtasetForeground(Colorred);

} } );

jmdb3addActionListener(new ActionListener() //绿色

{ public void actionPerformed(ActionEvent e)

{ jtasetForeground(Colorgreen);

} } );

jmdb4addActionListener(new ActionListener() //蓝色

{

public void actionPerformed(ActionEvent e)

{

jtasetForeground(Colorblue);

} } );

jmdb5addActionListener(new ActionListener() //黑色

{

public void actionPerformed(ActionEvent e)

{

jtasetForeground(Colorblack);

} } );

}

public void actionPerformed(ActionEvent e)

{ if(egetSource()==jmi1)//新建

{jtasetText("");

thissetTitle("无标题 - 记事本");

}

if(egetSource()==jmi2)//打开

{File f1;

JFileChooser jfc1 = new JFileChooser();

int num1 = jfc1showOpenDialog(this);

if(num1==JFileChooserAPPROVE_OPTION)

{ try {

f1 = jfc1getSelectedFile();

thissetTitle(f1getName());

FileReader fr = new FileReader(f1);

BufferedReader br = new BufferedReader(fr);

String str;

while((str = brreadLine())!=null)

{jtasetText(str);}

frclose();

brclose(); }

catch(FileNotFoundException e1)

{e1printStackTrace();}

catch(IOException e2){e2printStackTrace();}

}}

if(egetSource()==jmi3)//保存

{File f2 = null;

JFileChooser jfc2 = new JFileChooser();

int num2 = jfc2showSaveDialog(this);

if(num2==JFileChooserAPPROVE_OPTION){

f2=jfc2getSelectedFile();

thissetTitle(f2getName());

try{

FileWriter fw = new FileWriter(f2);

BufferedWriter bw = new BufferedWriter(fw);

bwwrite(jtagetText());

bwclose();

fwclose();

}catch(IOException e2){

e2printStackTrace();

}}}

if(egetSource()==jmi4)//退出

{

int a = JOptionPaneshowConfirmDialog(this,"文件已被改变，是否要保存？","提示",JOptionPaneYES_NO_CANCEL_OPTION);

if(a==1){

thisdispose();

}else if(a==0){

File f2 = null;

JFileChooser jfc2 = new JFileChooser();

int num2 = jfc2showSaveDialog(this);

if(num2==JFileChooserAPPROVE_OPTION){

f2=jfc2getSelectedFile();

thissetTitle(f2getName());

try{

FileWriter fw = new FileWriter(f2);

BufferedWriter bw = new BufferedWriter(fw);

bwwrite(jtagetText());

bwclose();

fwclose();

}catch(IOException e2){

e2printStackTrace();

}

thisdispose();

}}}

if(egetSource()==jmp1)//日期时间

{

Calendar c1 =CalendargetInstance();

int y = c1get(CalendarYEAR);

int m = c1get(CalendarMONTH);

int d = c1get(CalendarDATE);

int h = c1get(CalendarHOUR);

int m1 = c1get(CalendarMINUTE);

int m2 = m+1;

jtasetText(y+"年"+m2+"月"+d+"日"+h+":"+m1);

}

if(egetSource()==jmp2)//背景色

{ Color ccc = JColorChoosershowDialog(this,"color",ColorBLACK);

jtasetSelectedTextColor(ccc);

jtasetBackground(ccc);

}

if(egetSource()==jButton1)//打开

{File f1;

JFileChooser jfc1 = new JFileChooser();

int num1 = jfc1showOpenDialog(this);

if(num1==JFileChooserAPPROVE_OPTION)

{

try

{

f1 = jfc1getSelectedFile();

thissetTitle(f1getName());

FileReader fr = new FileReader(f1);

BufferedReader br = new BufferedReader(fr);

String str;

while((str = brreadLine())!=null)

{jtasetText(str);}

frclose();

brclose(); }

catch(FileNotFoundException e1)

{e1printStackTrace();}

catch(IOException e2){e2printStackTrace();}

} }

if(egetSource()==jButton2)

{jtasetText("");

thissetTitle("文本编辑器");

}

if(egetSource()==jmi5){

jtareplaceRange("",jtagetSelectionStart(),jtagetSelectionEnd()); //删除

}

if(egetSource()==jButton3)

{File f2 = null;

JFileChooser jfc2 = new JFileChooser();

int num2 = jfc2showSaveDialog(this);

if(num2==JFileChooserAPPROVE_OPTION){

f2=jfc2getSelectedFile();

thissetTitle(f2getName());

try{

FileWriter fw = new FileWriter(f2);

BufferedWriter bw = new BufferedWriter(fw);

bwwrite(jtagetText());

bwclose();

fwclose();

}catch(IOException e2){

e2printStackTrace();

}}}

if(egetSource()==aa) //复制

{jtacopy();}

else if(egetSource()==bb)//剪切

{ jtacut(); }

else if(egetSource()==cc)//粘贴

{jtapaste();}

if(egetSource()==jButton4)

{int a = JOptionPaneshowConfirmDialog(this,"文件已被改变，是否要保存？","提示",JOptionPaneYES_NO_CANCEL_OPTION);

if(a==1){

thisdispose();

}else if(a==0){

File f2 = null;

JFileChooser jfc2 = new JFileChooser();

int num2 = jfc2showSaveDialog(this);

if(num2==JFileChooserAPPROVE_OPTION){

f2=jfc2getSelectedFile();

thissetTitle(f2getName());

try{

FileWriter fw = new FileWriter(f2);

BufferedWriter bw = new BufferedWriter(fw);

bwwrite(jtagetText());

bwclose();

fwclose();

}catch(IOException e2){

e2printStackTrace();

}

thisdispose();

}}}

//if(egetSource()==jmi7)//关于我

//{About1 a=new About1();//实现跳转

// asetVisible(true);

//}

}

public void itemStateChanged(ItemEvent e) //字体

{Font c=new Font("Serif",FontPLAIN,14);

if(egetItemSelectable()==jcuti1)

{if(jcuti1getState()==true)

{ Font f=new Font("Serif",FontBOLD,20); //粗体

jtasetFont(f);}

else{jtasetFont(c);}

}

else if(egetItemSelectable()==jxieti1)

{if(jxieti1getState()==true)

{ Font b=new Font("Serif",FontITALIC,20);//斜体

jtasetFont(b);}

else{jtasetFont(c);

} } }

public static void main(String[] args)//入口

{ new NoteBook(); }

public void windowOpened(WindowEvent arg0) {}

public void windowClosing(WindowEvent arg0) {

int a = JOptionPaneshowConfirmDialog(this,"文件已被改变，是否要保存？","提示",JOptionPaneYES_NO_CANCEL_OPTION);

if(a==1){

thisdispose();

}else if(a==0){

File f2 = null;

JFileChooser jfc2 = new JFileChooser();

int num2 = jfc2showSaveDialog(this);

if(num2==JFileChooserAPPROVE_OPTION){

f2=jfc2getSelectedFile();

thissetTitle(f2getName());

try{

FileWriter fw = new FileWriter(f2);

BufferedWriter bw = new BufferedWriter(fw);

bwwrite(jtagetText());

bwclose();

fwclose();

}catch(IOException e2){

e2printStackTrace();

}

}

if(a==2){}

}

}

public void windowClosed(WindowEvent arg0) {}

public void windowIconified(WindowEvent arg0) {}

public void windowDeiconified(WindowEvent arg0) {}

public void windowActivated(WindowEvent arg0) {}

public void windowDeactivated(WindowEvent arg0) {}

public void mouseClicked(MouseEvent arg0) {}

public void mousePressed(MouseEvent arg0) {}

public void mouseReleased(MouseEvent arg0) {}

public void mouseEntered(MouseEvent arg0) {}

public void mouseExited(MouseEvent arg0) {}

}

public class TestStar {

public static void main(String[] args) {

String star = "";

for (int i = 0; i < 5; i++) {

if (i == 0) {

Systemoutprint(" " + star);

Systemoutprintln();

}

if (i == 1) {

for (int z = 0; z < 4; z++) {

Systemoutprint(" " + star);

}

Systemoutprintln();

}

if (i == 2) {

Systemoutprint(" ");

for (int x = 0; x < 3; x++) {

Systemoutprint(" " + star);

}

Systemoutprintln();

}

if (i == 3) {

for (int y = 0; y < 2; y++) {

Systemoutprint(" " + star + " ");

}

}

}

}

}

是好使的 但是我没找到画五角星有什么规律（五角星好象不是正规图形吧？）如果还有什么要求的话 补充问题(如果是用填充所有的东西 不包括 “ ”的话 我可以重新再给你写一个)

class Ball {

public void play() {

Systemoutprintln("玩球儿");

}

}

class Football extends Ball {

public void play() {

Systemoutprintln("使用足球运动");

}

}

class Basketball extends Ball {

public void play() {

Systemoutprintln("使用篮球运动");

}

}

public class TestMain {

public static void main(String[] args) {

TestMain tm = new TestMain();

tmtestPlay();

}

public void testPlay() {

Ball ball = new Football();

ballplay();

ball = new Basketball();

ballplay();

}

}

/

D:\>javac TestMainjava

D:\>java TestMain

使用足球运动

使用篮球运动

/

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