这是我晓得的最简单的java小程序代码了你可以看看:
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package com.kenki.emp;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.sql.SQLException;
import java.sql.*;
public class emp extends HttpServlet {
private static final String CONTENT_TYPE = "text/html; charset=GBK";
//Initialize global variables
public void init() throws ServletException {
}
//Process the HTTP Get request
public void doGet(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
response.setContentType(CONTENT_TYPE);
PrintWriter out = response.getWriter();
String code = request.getParameter("code");
String name = request.getParameter("name");
String pay = request.getParameter("pay");
System.out.println("empcode:" + code);
System.out.println("name:" + name);
System.out.println("pay:" + pay);
//创建驱动
new com.microsoft.jdbc.sqlserver.SQLServerDriver();
String strd =
"jdbc:microsoft:sqlserver://localhost:1433;databasename=emp_dates";
String username = "sa";
String pws = "";
try {
java.sql.Connection conn = java.sql.DriverManager.getConnection(
strd, username, pws);
String strs = "insert into emp values(?,?,?)";
java.sql.PreparedStatement pre = conn.prepareStatement(strs);
pre.setString(1, code);
pre.setString(2, name);
pre.setString(3, pay);
pre.execute();
pre.close();
conn.close();
//重定向至查询页面
out.println("成功保存！！");
response.sendRedirect("emp.html");
} catch (SQLException ss) {
ss.printStackTrace();
response.sendRedirect("/WebModule1/error.html");
}
}
//Process the HTTP Post request
public void doPost(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
doGet(request, response);
}
//Clean up resources
public void destroy() {
}
}
用MVC方式实现的贪吃蛇游戏，共有4个类。运行GreedSnake运行即可。主要是观察者模式的使用，我已经添加了很多注释了。
1、
/*
* 程序名称：贪食蛇
* 原作者：BigF
* 修改者：algo
* 说明：我以前也用C写过这个程序，现在看到BigF用Java写的这个，发现虽然作者自称是Java的初学者，
* 但是明显编写程序的素养不错，程序结构写得很清晰，有些细微得地方也写得很简洁，一时兴起之
* 下，我认真解读了这个程序，发现数据和表现分开得很好，而我近日正在学习MVC设计模式，
* 因此尝试把程序得结构改了一下，用MVC模式来实现，对源程序得改动不多。
* 我同时也为程序增加了一些自己理解得注释，希望对大家阅读有帮助。
*/
package mvcTest;
/**
* @author WangYu
* @version 1.0
* Description:
* /pre
* Create on :Date :2005-6-13 Time:15:57:16
* LastModified:
* History:
*/
public class GreedSnake {
public static void main(String[] args) {
SnakeModel model = new SnakeModel(20,30);
SnakeControl control = new SnakeControl(model);
SnakeView view = new SnakeView(model,control);
//添加一个观察者，让view成为model的观察者
model.addObserver(view);
(new Thread(model)).start();
}
}
-------------------------------------------------------------
2、
package mvcTest;
//SnakeControl.java
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
/**
* MVC中的Controler，负责接收用户的操作，并把用户操作通知Model
*/
public class SnakeControl implements KeyListener{
SnakeModel model;
public SnakeControl(SnakeModel model){
this.model = model;
}
public void keyPressed(KeyEvent e) {
int keyCode = e.getKeyCode();
if (model.running){ // 运行状态下，处理的按键
switch (keyCode) {
case KeyEvent.VK_UP:
model.changeDirection(SnakeModel.UP);
break;
case KeyEvent.VK_DOWN:
model.changeDirection(SnakeModel.DOWN);
break;
case KeyEvent.VK_LEFT:
model.changeDirection(SnakeModel.LEFT);
break;
case KeyEvent.VK_RIGHT:
model.changeDirection(SnakeModel.RIGHT);
break;
case KeyEvent.VK_ADD:
case KeyEvent.VK_PAGE_UP:
model.speedUp();
break;
case KeyEvent.VK_SUBTRACT:
case KeyEvent.VK_PAGE_DOWN:
model.speedDown();
break;
case KeyEvent.VK_SPACE:
case KeyEvent.VK_P:
model.changePauseState();
break;
default:
}
}
// 任何情况下处理的按键，按键导致重新启动游戏
if (keyCode == KeyEvent.VK_R ||
keyCode == KeyEvent.VK_S ||
keyCode == KeyEvent.VK_ENTER) {
model.reset();
}
}
public void keyReleased(KeyEvent e) {
}
public void keyTyped(KeyEvent e) {
}
}
-------------------------------------------------------------
3、
/*
*
*/
package mvcTest;
/**
* 游戏的Model类，负责所有游戏相关数据及运行
* @author WangYu
* @version 1.0
* Description:
* /pre
* Create on :Date :2005-6-13 Time:15:58:33
* LastModified:
* History:
*/
//SnakeModel.java
import javax.swing.*;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Observable;
import java.util.Random;
/**
* 游戏的Model类，负责所有游戏相关数据及运行
*/
class SnakeModel extends Observable implements Runnable {
boolean[][] matrix; // 指示位置上有没蛇体或食物
LinkedList nodeArray = new LinkedList(); // 蛇体
Node food;
int maxX;
int maxY;
int direction = 2; // 蛇运行的方向
boolean running = false; // 运行状态
int timeInterval = 200; // 时间间隔，毫秒
double speedChangeRate = 0.75; // 每次得速度变化率
boolean paused = false; // 暂停标志
int score = 0; // 得分
int countMove = 0; // 吃到食物前移动的次数
// UP and DOWN should be even
// RIGHT and LEFT should be odd
public static final int UP = 2;
public static final int DOWN = 4;
public static final int LEFT = 1;
public static final int RIGHT = 3;
public SnakeModel( int maxX, int maxY) {
this.maxX = maxX;
this.maxY = maxY;
reset();
}
public void reset(){
direction = SnakeModel.UP; // 蛇运行的方向
timeInterval = 200; // 时间间隔，毫秒
paused = false; // 暂停标志
score = 0; // 得分
countMove = 0; // 吃到食物前移动的次数
// initial matirx, 全部清0
matrix = new boolean[maxX][];
for (int i = 0; i maxX; ++i) {
matrix[i] = new boolean[maxY];
Arrays.fill(matrix[i], false);
}
// initial the snake
// 初始化蛇体，如果横向位置超过20个，长度为10，否则为横向位置的一半
int initArrayLength = maxX 20 ? 10 : maxX / 2;
nodeArray.clear();
for (int i = 0; i initArrayLength; ++i) {
int x = maxX / 2 + i;//maxX被初始化为20
int y = maxY / 2; //maxY被初始化为30
//nodeArray[x,y]: [10,15]-[11,15]-[12，15]~~[20,15]
//默认的运行方向向上，所以游戏一开始nodeArray就变为：
// [10，14]-[10，15]-[11，15]-[12，15]~~[19，15]
nodeArray.addLast(new Node(x, y));
matrix[x][y] = true;
}
// 创建食物
food = createFood();
matrix[food.x][food.y] = true;
}
public void changeDirection(int newDirection) {
// 改变的方向不能与原来方向同向或反向
if (direction % 2 != newDirection % 2) {
direction = newDirection;
}
}
/**
* 运行一次
* @return
*/
public boolean moveOn() {
Node n = (Node) nodeArray.getFirst();
int x = n.x;
int y = n.y;
// 根据方向增减坐标值
switch (direction) {
case UP:
y--;
break;
case DOWN:
y++;
break;
case LEFT:
x--;
break;
case RIGHT:
x++;
break;
}
// 如果新坐标落在有效范围内，则进行处理
if ((0 = x x maxX) (0 = y y maxY)) {
if (matrix[x][y]) { // 如果新坐标的点上有东西（蛇体或者食物）
if (x == food.x y == food.y) { // 吃到食物，成功
nodeArray.addFirst(food); // 从蛇头赠长
// 分数规则，与移动改变方向的次数和速度两个元素有关
int scoreGet = (10000 - 200 * countMove) / timeInterval;
score += scoreGet 0 ? scoreGet : 10;
countMove = 0;
food = createFood(); // 创建新的食物
matrix[food.x][food.y] = true; // 设置食物所在位置
return true;
} else // 吃到蛇体自身，失败
return false;
} else { // 如果新坐标的点上没有东西（蛇体），移动蛇体
nodeArray.addFirst(new Node(x, y));
matrix[x][y] = true;
n = (Node) nodeArray.removeLast();
matrix[n.x][n.y] = false;
countMove++;
return true;
}
}
return false; // 触到边线，失败
}
public void run() {
running = true;
while (running) {
try {
Thread.sleep(timeInterval);
} catch (Exception e) {
break;
}
if (!paused) {
if (moveOn()) {
setChanged(); // Model通知View数据已经更新
notifyObservers();
} else {
JOptionPane.showMessageDialog(null,
"you failed",
"Game Over",
JOptionPane.INFORMATION_MESSAGE);
break;
}
}
}
running = false;
}
private Node createFood() {
int x = 0;
int y = 0;
// 随机获取一个有效区域内的与蛇体和食物不重叠的位置
do {
Random r = new Random();
x = r.nextInt(maxX);
y = r.nextInt(maxY);
} while (matrix[x][y]);
return new Node(x, y);
}
public void speedUp() {
timeInterval *= speedChangeRate;
}
public void speedDown() {
timeInterval /= speedChangeRate;
}
public void changePauseState() {
paused = !paused;
}
public String toString() {
String result = "";
for (int i = 0; i nodeArray.size(); ++i) {
Node n = (Node) nodeArray.get(i);
result += "[" + n.x + "," + n.y + "]";
}
return result;
}
}
class Node {
int x;
int y;
Node(int x, int y) {
this.x = x;
this.y = y;
}
}
------------------------------------------------------------
4、
package mvcTest;
//SnakeView.java
import javax.swing.*;
import java.awt.*;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Observable;
import java.util.Observer;
/**
* MVC模式中得Viewer，只负责对数据的显示,而不用理会游戏的控制逻辑
*/
public class SnakeView implements Observer {
SnakeControl control = null;
SnakeModel model = null;
JFrame mainFrame;
Canvas paintCanvas;
JLabel labelScore;
public static final int canvasWidth = 200;
public static final int canvasHeight = 300;
public static final int nodeWidth = 10;
public static final int nodeHeight = 10;
public SnakeView(SnakeModel model, SnakeControl control) {
this.model = model;
this.control = control;
mainFrame = new JFrame("GreedSnake");
Container cp = mainFrame.getContentPane();
// 创建顶部的分数显示
labelScore = new JLabel("Score:");
cp.add(labelScore, BorderLayout.NORTH);
// 创建中间的游戏显示区域
paintCanvas = new Canvas();
paintCanvas.setSize(canvasWidth + 1, canvasHeight + 1);
paintCanvas.addKeyListener(control);
cp.add(paintCanvas, BorderLayout.CENTER);
// 创建底下的帮助栏
JPanel panelButtom = new JPanel();
panelButtom.setLayout(new BorderLayout());
JLabel labelHelp;
labelHelp = new JLabel("PageUp, PageDown for speed;", JLabel.CENTER);
panelButtom.add(labelHelp, BorderLayout.NORTH);
labelHelp = new JLabel("ENTER or R or S for start;", JLabel.CENTER);
panelButtom.add(labelHelp, BorderLayout.CENTER);
labelHelp = new JLabel("SPACE or P for pause", JLabel.CENTER);
panelButtom.add(labelHelp, BorderLayout.SOUTH);
cp.add(panelButtom, BorderLayout.SOUTH);
mainFrame.addKeyListener(control);
mainFrame.pack();
mainFrame.setResizable(false);
mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainFrame.setVisible(true);
}
void repaint() {
Graphics g = paintCanvas.getGraphics();
//draw background
g.setColor(Color.WHITE);
g.fillRect(0, 0, canvasWidth, canvasHeight);
// draw the snake
g.setColor(Color.BLACK);
LinkedList na = model.nodeArray;
Iterator it = na.iterator();
while (it.hasNext()) {
Node n = (Node) it.next();
drawNode(g, n);
}
// draw the food
g.setColor(Color.RED);
Node n = model.food;
drawNode(g, n);
updateScore();
}
private void drawNode(Graphics g, Node n) {
g.fillRect(n.x * nodeWidth,
n.y * nodeHeight,
nodeWidth - 1,
nodeHeight - 1);
}
public void updateScore() {
String s = "Score: " + model.score;
labelScore.setText(s);
}
public void update(Observable o, Object arg) {
repaint();
}
}
希望采纳
代码如下：
public class HelloWorld {
public static void main(String []args) {
int a = 3, b = 7 ;
System.out.println("Hello World!");
}
public static int f(int a, int b){
return a*a + a*b + b*b;
}
}
结果如下：
/*计算器*/
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;
public class Calculator implements ActionListener{
JFrame frame;
JPanel panel;
JTextField tfShow;/*定义显示文本框*/
JButton b1[]=new JButton[10]; /*数字按钮*/
JButton b2[]=new JButton[6]; /*操作按钮*/
boolean isNumber;/*判断是否输入多位数字的变量*/
double number;/*存储输入数值、显示结果的变量*/
double result;/*存储中间运算结果的变量*/
char operator;/*存储当前操作符的成员变量*/
public Calculator(){
frame=new JFrame("计算器");
frame.setSize(300,300);/*指定框架窗口的大小*/
frame.setResizable(false);/*使框架窗口不可改变大小*/
JPanel contentPane=(JPanel)frame.getContentPane();
contentPane.setBorder(new EmptyBorder(20,20,20,20));/*绘制框架的指定大小的空透明边框*/
tfShow=new JTextField("0",25);/*指定属性的文本域*/
tfShow.setHorizontalAlignment(JTextField.RIGHT);/*设置文本域中文本的对齐方式*/
isNumber=true;/*初始值设置*/
number=0;/*初始值设置*/
result=0;/*初始值设置*/
operator=' ';/*初始值设置*/
for(int i=0;ib1.length;i++){
b1[i]=new JButton(Integer.toString(i));/*创建数字按钮*/
b1[i].setActionCommand(Integer.toString(i));
b1[i].addActionListener(this);
b1[i].setForeground(Color.blue);
}
String bs[]={"/","*","-","C","+","="};
for(int i=0;ib2.length;i++){
b2[i]=new JButton(bs[i]);/*创建操作按钮*/
b2[i].setActionCommand(bs[i]);
b2[i].addActionListener(this);
b2[i].setForeground(Color.red);
}
panel=new JPanel();
panel.setLayout(new GridLayout(4,5));
panel.add(b1[1]);
panel.add(b1[2]);
panel.add(b1[3]);
panel.add(b2[0]);
panel.add(b1[4]);
panel.add(b1[5]);
panel.add(b1[6]);
panel.add(b2[1]);
panel.add(b1[7]);
panel.add(b1[8]);
panel.add(b1[9]);
panel.add(b2[2]);
panel.add(b1[0]);
panel.add(b2[3]);
panel.add(b2[4]);
panel.add(b2[5]);
frame.add(tfShow,BorderLayout.NORTH);/*将文本框放置在框架上方*/
frame.add(panel,BorderLayout.CENTER);/*将装有按钮组的panel放在框架的中心*/
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);/*设置框架窗口的默认窗口关闭操作*/
frame.setVisible(true);/*设置框架可见*/
}
public double getDisplay(){/*返回要显示的结果*/
return number;
}
public void reDisplay(){/*刷新文本域的内容*/
tfShow.setText(""+getDisplay());
}
/*对输入数字的处理*/
public void numberProcess(int num){
if(isNumbernum!=0){
String s1=Integer.toString(num);
String s2=Integer.toString((int)(this.number));
this.number=Double.parseDouble(s2+s1);/*对多位数字的处理*/
}else{
this.number=num;
}
isNumber=true;/*输入连续数字（即多位数字）时为真*/
}
public void operationProcess(char operator){/*根据输入的操作符改变当前操作符*/
switch(operator){
case '-':
this.operator='-';
break;
case '+':
this.operator='+';
break;
case '*':
this.operator='*';
break;
case '/':
this.operator='/';
break;
}
result=number;
isNumber=false;/*输入操作符时表示输入连续数字的标记变量为假*/
}
public void clear(){
number=0;
result=0;
}
public void equal(){/*计算运算结果*/
switch(operator){
case '-':
result=result-number;
break;
case '+':
result=result+number;
break;
case '*':
result=result*number;
break;
case '/':
result=result/number;
break;
case ' ':
result=number;
break;
}
number=result; /*把运算结果赋值给显示变量*/
isNumber=false;
operator=' ';
}
public static void main(String args[]){
Calculator cal=new Calculator();/*创建计算器*/
}
public void actionPerformed(ActionEvent e){
String command=e.getActionCommand();/*获取按钮激发的操作事件的命令名称*/
char c=command.charAt(0);/*将按钮命令名称的第一个字符赋值给一个字符c*/
switch(c){
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case '0':
int number=Integer.parseInt(command);
numberProcess(number);/*输入数字的处理*/
break;
case '+':
case '-':
case '*':
case '/':
operationProcess(c);/*算数运算符的处理*/
break;
case '=':equal();break;/*计算运算结果*/
case 'C':clear();break;/*清零*/
}
reDisplay(); /*在文本域中显示信息*/
}
}
运行截图：
