Java里的字节码和源代码分别啥意思，和起到什么左右

/*java是一门高级编程语言，是用来写程序代码的。

目前创新互联已为近千家的企业提供了网站建设、域名、网页空间、网站托管运营、企业网站设计、达坂城网站维护等服务，公司将坚持客户导向、应用为本的策略，正道将秉承"和谐、参与、激情"的文化，与客户和合作伙伴齐心协力一起成长，共同发展。

用java写的文本（字符串序列）就是源代码。

计算机不能直接执行源代码，必须用一个叫编译器的程序（javac.exe）将源代码

翻译成字节码，然后让一个叫解释器的程序（java.exe）去执行字节码，即运行程序。

下面的就是一个小程序的源代码，功能是输出九九乘法表。

下图中的Test.class就是这个源代码文件翻译后的由字节码组成的文件。

而最下面的那个黑框就是程序执行后的结果。

java Test就是在执行Test.class字节码文件，即运行这个程序。

*/

//这下面的就是源代码

public class Test {

public static void main(String[] args) {

int i,j;

for(i=1;i=9;i++) {

for(j=1;j=i;j++)

System.out.printf("%dx%d=%-4d",j,i,j*i);

System.out.println();

}

}

}

java简单记事本源代码 带解释

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import javax.swing.border.*;

class test implements ActionListener

{

JFrame frame;

JButton b1,b2,b3,b4,b5,b6,b7,b8,b9,b10,b11,b12,b13,b14,b15,b16,b17,b18,b19,b20,b21,b22,b23,b24,b25,b26,b27,b28,b29,b30,b31;

JTextArea ta;

JPanel p1,p2,p3,p4;

JMenuBar mb;

JMenu m1,m2,m3;

JMenuItem mt1,mt2,mt3,mt4,mt5,mt6,mt7;

JRadioButton rb1,rb2;

ButtonGroup bg;

Double d1=0.0,d2=0.0,d3=0.0,d4=1.0,d5=1.0;

String s1="",s2="",s3="",s4="";

int a=0;

char c1;

int i=0;

public static void main(String[] args)

{

test that=new test();

that.go();

}

public void go()

{

frame=new JFrame("计算器");

Container cp= frame.getContentPane();

cp.setLayout(new FlowLayout());

b1=new JButton("7");b2=new JButton("8");b3=new JButton("9");b4=new JButton("/");b5=new JButton("1/x");b6=new JButton("sin");b7=new JButton("log");

b8=new JButton("4");b9=new JButton("5");b10=new JButton("6");b11=new JButton("*");b12=new JButton("x^y");b13=new JButton("cos");b14=new JButton("ln");

b15=new JButton("1");b16=new JButton("2");b17=new JButton("3");b18=new JButton("-");b19=new JButton(new ImageIcon("lanying.gif"));b20=new JButton("tan");b21=new JButton("x^3");

b22=new JButton("0");b23=new JButton("+/-");b24=new JButton(".");b25=new JButton("+");b26=new JButton("√x");b27=new JButton("cot");b28=new JButton("x^2");

b29=new JButton("Backspace");b30=new JButton("C");b31=new JButton("=");

mb=new JMenuBar();

m1=new JMenu("文件(F)");m2=new JMenu("编辑(E)");m3=new JMenu("帮助(H)");

mt1=new JMenuItem("清零");mt2=new JMenuItem("退出");mt3=new JMenuItem("复制");mt4=new JMenuItem("粘贴");mt5=new JMenuItem("版本");mt6=new JMenuItem("标准型");mt7=new JMenuItem("科学型");

ta=new JTextArea(1,30);

p1=new JPanel();p2=new JPanel();p3=new JPanel();p4=new JPanel();

rb1=new JRadioButton("科学型");rb2=new JRadioButton("标准型");

bg=new ButtonGroup();

b1.setForeground(Color.blue);b1.setBackground(Color.white);b2.setForeground(Color.blue);b2.setBackground(Color.white);

b3.setForeground(Color.blue);b3.setBackground(Color.white);b8.setForeground(Color.blue);b8.setBackground(Color.white);

b9.setForeground(Color.blue);b9.setBackground(Color.white);b10.setForeground(Color.blue);b10.setBackground(Color.white);

b15.setForeground(Color.blue);b15.setBackground(Color.white);b16.setForeground(Color.blue);b16.setBackground(Color.white);

b17.setForeground(Color.blue);b17.setBackground(Color.white);b22.setForeground(Color.blue);b22.setBackground(Color.white);

b23.setForeground(Color.blue);b23.setBackground(Color.white);b24.setForeground(Color.blue);b24.setBackground(Color.white);

b4.setForeground(Color.red);b4.setBackground(Color.white);b11.setForeground(Color.red);b11.setBackground(Color.white);

b18.setForeground(Color.red);b18.setBackground(Color.white);b25.setForeground(Color.red);b25.setBackground(Color.white);

b5.setForeground(Color.blue);b5.setBackground(Color.white);b6.setForeground(Color.blue);b6.setBackground(Color.white);

b7.setForeground(Color.blue);b7.setBackground(Color.white);b12.setForeground(Color.blue);b12.setBackground(Color.white);

b13.setForeground(Color.blue);b13.setBackground(Color.white);b14.setForeground(Color.blue);b14.setBackground(Color.white);

b19.setForeground(Color.blue);b19.setBackground(Color.white);b20.setForeground(Color.blue);b20.setBackground(Color.white);

b21.setForeground(Color.blue);b21.setBackground(Color.white);b26.setForeground(Color.blue);b26.setBackground(Color.white);

b27.setForeground(Color.blue);b27.setBackground(Color.white);b28.setForeground(Color.blue);b28.setBackground(Color.white);

b29.setForeground(Color.red);b29.setBackground(Color.white);b30.setForeground(Color.red);b30.setBackground(Color.white);

b31.setForeground(Color.red);b31.setBackground(Color.white);

bg.add(rb1);bg.add(rb2);

p1.setBackground(Color.yellow);

cp.setBackground(Color.CYAN);

m1.setMnemonic(KeyEvent.VK_F);m2.setMnemonic(KeyEvent.VK_E);m3.setMnemonic(KeyEvent.VK_H);

m1.add(mt6);m1.add(mt7);m1.addSeparator();m1.add(mt1);m1.addSeparator();m1.add(mt2);m2.add(mt3);m2.addSeparator();m2.add(mt4);m3.add(mt5);

mb.add(m1);mb.add(m2);mb.add(m3);

frame.setJMenuBar(mb);

p2.setLayout(new GridLayout(4,7));

p3.setLayout(new GridLayout(1,3));

ta.setEditable(false);

p1.add(ta);

p2.add(b1);p2.add(b2);p2.add(b3);p2.add(b4);p2.add(b5);p2.add(b6);p2.add(b7);

p2.add(b8);p2.add(b9);p2.add(b10);p2.add(b11);p2.add(b12);p2.add(b13);p2.add(b14);

p2.add(b15);p2.add(b16);p2.add(b17);p2.add(b18);p2.add(b19);p2.add(b20);p2.add(b21);

p2.add(b22);p2.add(b23);p2.add(b24);p2.add(b25);p2.add(b26);p2.add(b27);p2.add(b28);

p3.add(b29);p3.add(b30);p3.add(b31);

Border etched=BorderFactory.createEtchedBorder();

Border border=BorderFactory.createTitledBorder(etched,"计算类型");

p4.add(rb1);p4.add(rb2);

p4.setBorder(border);

b2.setActionCommand("8");

b2.addActionListener(this);

cp.add(p1);cp.add(p4);cp.add(p2);cp.add(p3);

frame.setSize(400,330);

frame.setVisible(true);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

b1.setActionCommand("7");

b1.addActionListener(this);

b2.setActionCommand("8");

b2.addActionListener(this);

b3.setActionCommand("9");

b3.addActionListener(this);

b4.setActionCommand("/");

b4.addActionListener(this);

b5.setActionCommand("1/x");

b5.addActionListener(this);

b6.setActionCommand("sin");

b6.addActionListener(this);

b7.setActionCommand("log");

b7.addActionListener(this);

b8.setActionCommand("4");

b8.addActionListener(this);

b9.setActionCommand("5");

b9.addActionListener(this);

b10.setActionCommand("6");

b10.addActionListener(this);

b11.setActionCommand("*");

b11.addActionListener(this);

b12.setActionCommand("x^y");

b12.addActionListener(this);

b13.setActionCommand("cos");

b13.addActionListener(this);

b14.setActionCommand("ln");

b14.addActionListener(this);

b15.setActionCommand("1");

b15.addActionListener(this);

b16.setActionCommand("2");

b16.addActionListener(this);

b17.setActionCommand("3");

b17.addActionListener(this);

b18.setActionCommand("-");

b18.addActionListener(this);

b19.setActionCommand("x!");

b19.addActionListener(this);

b20.setActionCommand("tan");

b20.addActionListener(this);

b21.setActionCommand("x^3");

b21.addActionListener(this);

b22.setActionCommand("0");

b22.addActionListener(this);

b23.setActionCommand("+/-");

b23.addActionListener(this);

b24.setActionCommand(".");

b24.addActionListener(this);

b25.setActionCommand("+");

b25.addActionListener(this);

b26.setActionCommand("√x");

b26.addActionListener(this);

b27.setActionCommand("cot");

b27.addActionListener(this);

b28.setActionCommand("x^2");

b28.addActionListener(this);

b29.setActionCommand("Backspace");

b29.addActionListener(this);

b30.setActionCommand("C");

b30.addActionListener(this);

b31.setActionCommand("=");

b31.addActionListener(this);

rb1.setActionCommand("kxx");

rb1.addActionListener(this);

rb2.setActionCommand("bzx");

rb2.addActionListener(this);

}

public void actionPerformed(ActionEvent e) //throws Exception

{

if (e.getActionCommand()=="bzx")

{

b5.setEnabled(false);b6.setEnabled(false);b7.setEnabled(false);

b12.setEnabled(false);b13.setEnabled(false);b14.setEnabled(false);

b19.setEnabled(false);b20.setEnabled(false);b21.setEnabled(false);

b26.setEnabled(false);b27.setEnabled(false);b28.setEnabled(false);

}

if (e.getActionCommand()=="kxx")

{

b5.setEnabled(true);b6.setEnabled(true);b7.setEnabled(true);

b12.setEnabled(true);b13.setEnabled(true);b14.setEnabled(true);

b19.setEnabled(true);b20.setEnabled(true);b21.setEnabled(true);

b26.setEnabled(true);b27.setEnabled(true);b28.setEnabled(true);

}

if (e.getActionCommand()=="1")

{

ta.append("1");

}

if (e.getActionCommand()=="2")

{

ta.append("2");

}

if (e.getActionCommand()=="3")

{

ta.append("3");

}

if (e.getActionCommand()=="4")

{

ta.append("4");

}

if (e.getActionCommand()=="5")

{

ta.append("5");

}

if (e.getActionCommand()=="6")

{

ta.append("6");

}

if (e.getActionCommand()=="7")

{

ta.append("7");

}

if (e.getActionCommand()=="8")

{

ta.append("8");

}

if (e.getActionCommand()=="9")

{

ta.append("9");

}

if (e.getActionCommand()=="0")

{

ta.append("0");

}

if (e.getActionCommand()=="+")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

ta.setText("");

i=1;

}

if (e.getActionCommand()=="-")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

ta.setText("");

i=2;

}

if (e.getActionCommand()=="*")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

ta.setText("");

i=3;

}

if (e.getActionCommand()=="/")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

ta.setText("");

i=4;

}

if (e.getActionCommand()=="=")

{

s2=ta.getText();

d2=Double.parseDouble(s2);

if(i==1)

{

d3=d1+d2;

ta.setText( d3.toString());

}

if(i==2)

{

d3=d1-d2;

ta.setText( d3.toString());

}

if(i==3)

{

d3=d1*d2;

ta.setText( d3.toString());

}

if(i==4)

{

if(d2==0.0)

ta.setText("ERROR");

else

{

d3=d1/d2;

ta.setText( d3.toString());

}

}

if (i==5)

{

s2=ta.getText();

d2 = Double.parseDouble(s2);

for (int l=1;l=d2 ; l++)

{

d5=d5*d1;

}

ta.setText( d5.toString());

}

}

if (e.getActionCommand()=="C")

{

ta.setText("");

d4=1.0;

d5=1.0;

}

/*if (e.getActionCommand()=="Backspace")

{

s3=ta.getText();

a=s3.length();

//ta.cut(ta.select(a-1,a));

s4=ta.getText(1,3);

ta.setText(s4);

}

*/

if (e.getActionCommand()=="1/x")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

d2=1/d1;

ta.setText( d2.toString());

}

if (e.getActionCommand()==".")

{

ta.append(".");

}

if (e.getActionCommand()=="+/-")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

d2=0-d1;

ta.setText( d2.toString());

}

if (e.getActionCommand()=="x^2")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

d2=d1*d1;

ta.setText( d2.toString());

}

if (e.getActionCommand()=="x^3")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

d2=d1*d1*d1;

ta.setText( d2.toString());

}

if (e.getActionCommand()=="x^y")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

ta.setText("");

i=5;

// d2=d1*d1*d1;

// ta.setText( d2.toString());

}

if (e.getActionCommand()=="√x")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

d2=Math.sqrt(d1);

ta.setText( d2.toString());

}

if (e.getActionCommand()=="x!")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

if (d10)

{

ta.setText( "error");

}

else if (d1==0)

{

ta.setText( "0.0");

}

else {

for (int k=1;k=d1 ;k++ )

d4=d4*k;

ta.setText( d4.toString());

}

}

if (e.getActionCommand()=="sin")

{

s1=ta.getText();

d1 = Double.parseDouble(s1);

d2=Math.sin(3.1415926*d1/180);

ta.setText( d2.toString());

}

}

}

跪地求好玩的JAVA 源代码~

连连看java源代码

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

public class lianliankan implements ActionListener

{

JFrame mainFrame; //主面板

Container thisContainer;

JPanel centerPanel,southPanel,northPanel; //子面板

JButton diamondsButton[][] = new JButton[6][5];//游戏按钮数组

JButton exitButton,resetButton,newlyButton; //退出，重列，重新开始按钮

JLabel fractionLable=new JLabel("0"); //分数标签

JButton firstButton,secondButton; //分别记录两次被选中的按钮

int grid[][] = new int[8][7];//储存游戏按钮位置

static boolean pressInformation=false; //判断是否有按钮被选中

int x0=0,y0=0,x=0,y=0,fristMsg=0,secondMsg=0,validateLV; //游戏按钮的位置坐标

int i,j,k,n;//消除方法控制

public void init(){

mainFrame=new JFrame("JKJ连连看");

thisContainer = mainFrame.getContentPane();

thisContainer.setLayout(new BorderLayout());

centerPanel=new JPanel();

southPanel=new JPanel();

northPanel=new JPanel();

thisContainer.add(centerPanel,"Center");

thisContainer.add(southPanel,"South");

thisContainer.add(northPanel,"North");

centerPanel.setLayout(new GridLayout(6,5));

for(int cols = 0;cols 6;cols++){

for(int rows = 0;rows 5;rows++ ){

diamondsButton[cols][rows]=new JButton(String.valueOf(grid[cols+1][rows+1]));

diamondsButton[cols][rows].addActionListener(this);

centerPanel.add(diamondsButton[cols][rows]);

}

}

exitButton=new JButton("退出");

exitButton.addActionListener(this);

resetButton=new JButton("重列");

resetButton.addActionListener(this);

newlyButton=new JButton("再来一局");

newlyButton.addActionListener(this);

southPanel.add(exitButton);

southPanel.add(resetButton);

southPanel.add(newlyButton);

fractionLable.setText(String.valueOf(Integer.parseInt(fractionLable.getText())));

northPanel.add(fractionLable);

mainFrame.setBounds(280,100,500,450);

mainFrame.setVisible(true);

}

public void randomBuild() {

int randoms,cols,rows;

for(int twins=1;twins=15;twins++) {

randoms=(int)(Math.random()*25+1);

for(int alike=1;alike=2;alike++) {

cols=(int)(Math.random()*6+1);

rows=(int)(Math.random()*5+1);

while(grid[cols][rows]!=0) {

cols=(int)(Math.random()*6+1);

rows=(int)(Math.random()*5+1);

}

this.grid[cols][rows]=randoms;

}

}

}

public void fraction(){

fractionLable.setText(String.valueOf(Integer.parseInt(fractionLable.getText())+100));

}

public void reload() {

int save[] = new int[30];

int n=0,cols,rows;

int grid[][]= new int[8][7];

for(int i=0;i=6;i++) {

for(int j=0;j=5;j++) {

if(this.grid[i][j]!=0) {

save[n]=this.grid[i][j];

n++;

}

}

}

n=n-1;

this.grid=grid;

while(n=0) {

cols=(int)(Math.random()*6+1);

rows=(int)(Math.random()*5+1);

while(grid[cols][rows]!=0) {

cols=(int)(Math.random()*6+1);

rows=(int)(Math.random()*5+1);

}

this.grid[cols][rows]=save[n];

n--;

}

mainFrame.setVisible(false);

pressInformation=false; //这里一定要将按钮点击信息归为初始

init();

for(int i = 0;i 6;i++){

for(int j = 0;j 5;j++ ){

if(grid[i+1][j+1]==0)

diamondsButton[i][j].setVisible(false);

}

}

}

public void estimateEven(int placeX,int placeY,JButton bz) {

if(pressInformation==false) {

x=placeX;

y=placeY;

secondMsg=grid[x][y];

secondButton=bz;

pressInformation=true;

}

else {

x0=x;

y0=y;

fristMsg=secondMsg;

firstButton=secondButton;

x=placeX;

y=placeY;

secondMsg=grid[x][y];

secondButton=bz;

if(fristMsg==secondMsg secondButton!=firstButton){

xiao();

}

}

}

public void xiao() { //相同的情况下能不能消去。仔细分析，不一条条注释

if((x0==x (y0==y+1||y0==y-1)) || ((x0==x+1||x0==x-1)(y0==y))){ //判断是否相邻

remove();

}

else{

for (j=0;j7;j++ ) {

if (grid[x0][j]==0){ //判断第一个按钮同行哪个按钮为空

if (yj) { //如果第二个按钮的Y坐标大于空按钮的Y坐标说明第一按钮在第二按钮左边

for (i=y-1;i=j;i-- ){ //判断第二按钮左侧直到第一按钮中间有没有按钮

if (grid[x][i]!=0) {

k=0;

break;

}

else{ k=1; } //K=1说明通过了第一次验证

}

if (k==1) {

linePassOne();

}

}

if (yj){ //如果第二个按钮的Y坐标小于空按钮的Y坐标说明第一按钮在第二按钮右边

for (i=y+1;i=j ;i++ ){ //判断第二按钮左侧直到第一按钮中间有没有按钮

if (grid[x][i]!=0){

k=0;

break;

}

else { k=1; }

}

if (k==1){

linePassOne();

}

}

if (y==j ) {

linePassOne();

}

}

if (k==2) {

if (x0==x) {

remove();

}

if (x0x) {

for (n=x0;n=x-1;n++ ) {

if (grid[n][j]!=0) {

k=0;

break;

}

if(grid[n][j]==0 n==x-1) {

remove();

}

}

}

if (x0x) {

for (n=x0;n=x+1 ;n-- ) {

if (grid[n][j]!=0) {

k=0;

break;

}

if(grid[n][j]==0 n==x+1) {

remove();

}

}

}

}

}

for (i=0;i8;i++ ) { //列

if (grid[i][y0]==0) {

if (xi) {

for (j=x-1;j=i ;j-- ) {

if (grid[j][y]!=0) {

k=0;

break;

}

else { k=1; }

}

if (k==1) {

rowPassOne();

}

}

if (xi) {

for (j=x+1;j=i;j++ ) {

if (grid[j][y]!=0) {

k=0;

break;

}

else { k=1; }

}

if (k==1) {

rowPassOne();

}

}

if (x==i) {

rowPassOne();

}

}

if (k==2){

if (y0==y) {

remove();

}

if (y0y) {

for (n=y0;n=y-1 ;n++ ) {

if (grid[i][n]!=0) {

k=0;

break;

}

if(grid[i][n]==0 n==y-1) {

remove();

}

}

}

if (y0y) {

for (n=y0;n=y+1 ;n--) {

if (grid[i][n]!=0) {

k=0;

break;

}

if(grid[i][n]==0 n==y+1) {

remove();

}

}

}

}

}

}

}

public void linePassOne(){

if (y0j){ //第一按钮同行空按钮在左边

for (i=y0-1;i=j ;i-- ){ //判断第一按钮同左侧空按钮之间有没按钮

if (grid[x0][i]!=0) {

k=0;

break;

}

else { k=2; } //K=2说明通过了第二次验证

}

}

if (y0j){ //第一按钮同行空按钮在与第二按钮之间

for (i=y0+1;i=j ;i++){

if (grid[x0][i]!=0) {

k=0;

break;

}

else{ k=2; }

}

}

}

public void rowPassOne(){

if (x0i) {

for (j=x0-1;j=i ;j-- ) {

if (grid[j][y0]!=0) {

k=0;

break;

}

else { k=2; }

}

}

if (x0i) {

for (j=x0+1;j=i ;j++ ) {

if (grid[j][y0]!=0) {

k=0;

break;

}

else { k=2; }

}

}

}

public void remove(){

firstButton.setVisible(false);

secondButton.setVisible(false);

fraction();

pressInformation=false;

k=0;

grid[x0][y0]=0;

grid[x][y]=0;

}

public void actionPerformed(ActionEvent e) {

if(e.getSource()==newlyButton){

int grid[][] = new int[8][7];

this.grid = grid;

randomBuild();

mainFrame.setVisible(false);

pressInformation=false;

init();

}

if(e.getSource()==exitButton)

System.exit(0);

if(e.getSource()==resetButton)

reload();

for(int cols = 0;cols 6;cols++){

for(int rows = 0;rows 5;rows++ ){

if(e.getSource()==diamondsButton[cols][rows])

estimateEven(cols+1,rows+1,diamondsButton[cols][rows]);

}

}

}

public static void main(String[] args) {

lianliankan llk = new lianliankan();

llk.randomBuild();

llk.init();

}

}

//old 998 lines

//new 318 lines

基于JAVA的3D坦克游戏源代码

JAVA猜数字小游戏源代码

/*1、编写一个猜数字的游戏，由电脑随机产生一个100以内的整数，让用户去猜，如果用户猜的比电脑大，则输出“大了，再小点！”，反之则输出“小了，再大点！”，用户总共只能猜十次，并根据用户正确猜出答案所用的次数输出相应的信息，如：只用一次就猜对，输出“你是个天才！”，八次才猜对，输出“笨死了！”,如果十次还没有猜对，则游戏结束！*/

import java.util.*;

import java.io.*;

public class CaiShu{

public static void main(String[] args) throws IOException{

Random a=new Random();

int num=a.nextInt(100);

System.out.println("请输入一个100以内的整数：");

for (int i=0;i=9;i++){

BufferedReader bf=new BufferedReader(new InputStreamReader(System.in));

String str=bf.readLine();

int shu=Integer.parseInt(str);

if (shunum)

System.out.println("输入的数大了，输小点的！");

else if (shunum)

System.out.println("输入的数小了，输大点的！");

else {

System.out.println("恭喜你，猜对了！");

if (i=2)

System.out.println("你真是个天才！");

else if (i=6)

System.out.println("还将就，你过关了！");

else if (i=8)

System.out.println("但是你还……真笨！");

else

System.out.println("你和猪没有两样了！");

break;}

}

}

}

用JAVA编程的通过SQL连接数据库的商品库存管理系统的源代码

package com.company.dao;

import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class BaseDao {

// 数据库驱动

String driver = "com.microsoft.sqlserver.jdbc.SQLServerDriver";

//url

String url = "jdbc:sqlserver://数据库ip:端口号;databaseName=数据库名;";

//用户名

String uname = "数据库用户名";

//密码

String pwd = "数据库密码";

/**

* 获得连接对象

* @return

*/

protected Connection getCon(){

//返回的连接

Connection con = null;

try {

//载入驱动

Class.forName(driver);

//得到连接

con = DriverManager.getConnection(url, uname, pwd);

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (SQLException e) {

e.printStackTrace();

}

return con;

}

/**

* 关闭数据库

* @param con

* @param stmt

* @param rs

*/

protected void closeDB(Connection con, Statement stmt, ResultSet rs){

if(rs != null){

try {

//关闭结果集

rs.close();

rs = null;

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

if(stmt != null){

try {

//关闭语句对象

stmt.close();

stmt = null;

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

if(con != null){

try {

//关闭连接对象

con.close();

con = null;

} catch (SQLException e) {

e.printStackTrace();

}

}

}

protected void closeDB(Connection con, PreparedStatement pstmt, ResultSet rs){

if(rs != null){

//关闭结果集

try {

rs.close();

rs = null;

} catch (SQLException e) {

e.printStackTrace();

}

}

if(pstmt != null){

try {

pstmt.close();

pstmt = null;

} catch (SQLException e) {

e.printStackTrace();

}

}

if(con != null){

try {

con.close();

con = null;

} catch (SQLException e) {

e.printStackTrace();

}

}

}

这个是我写的一个基本的连接sql2005数据库的代码,.! 不知道你能不能用,! 你看一下吧, 连接的时候需要sqljdbc.jar数据库驱动,!

求编写一个超级简单的Java的程序源代码

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

class ConstructFrame extends JFrame

{

private static final long serialVersionUID = 1L;

String value1="",result,value2="";

int flag=0,fix=0,sum=1;

Boolean happy;

JTextField text=new JTextField(30);

int flagsum=0;

Container c=getContentPane();

JButton buttonx;

ConstructFrame()

{ super("计算器");

c.setLayout(null);

c.setBackground(Color.blue);

this.setSize(400, 400);

c.add(text);

text.setHorizontalAlignment(JTextField.RIGHT);

final JButton buttonx=new JButton("BackSpace");

c.add(buttonx);

buttonx.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

int count=0;

String temp;

if(flag==0)

{

count=value1.length();

if(count!=1)

temp=value1.substring(0, count-1);

else

temp="0";

value1=temp;

}

else

{

count=value2.length();

if(count!=1)

temp=value2.substring(0, count-1);

else

temp="0";

value2=temp;

}

text.setText(temp);

}

});

final JButton buttony=new JButton("CE");

c.add(buttony);

buttony.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

value1="";

value2="";

flag=0;

text.setText("0");

}

});

final JButton button1=new JButton("1");

c.add(button1);

button1.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

String temp;

if(flag==0)

{

value1=value1+1;

temp=value1;

}

else

{

value2=value2+1;

temp=value2;

}

text.setText(temp);

}

});

final JButton button2=new JButton(" 2 ");

c.add(button2);

button2.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

String temp;

if(flag==0)

{

value1=value1+2;

temp=value1;

}

else

{

value2=value2+2;

temp=value2;

}

text.setText(temp);

}

});

final JButton button3=new JButton("3");

c.add(button3);

button3.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

String temp;

if(flag==0)

{

value1=value1+3;

temp=value1;

}

else

{

value2=value2+3;

temp=value2;

}

text.setText(temp);

}

});

final JButton button4=new JButton("4");

c.add(button4);

button4.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

String temp;

if(flag==0)

{

value1=value1+4;

temp=value1;

}

else

{

value2=value2+4;

temp=value2;

}

text.setText(temp);

}

});

final JButton button5=new JButton("5");

c.add(button5);

button5.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

String temp;

if(flag==0)

{

value1=value1+5;

temp=value1;

}

else

{

value2=value2+5;

temp=value2;

}

text.setText(temp);

}

});

final JButton button6=new JButton("6");

c.add(button6);

button6.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

String temp;

if(flag==0)

{

value1=value1+6;

temp=value1;

}

else

{

value2=value2+6;

temp=value2;

}

text.setText(temp);

}

});

final JButton button7=new JButton("7");

c.add(button7);

button7.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

String temp;

if(flag==0)

{

value1=value1+7;

temp=value1;

}

else

{

value2=value2+7;

temp=value2;

}

text.setText(temp);

}

});

final JButton button8=new JButton("8");

c.add(button8);

button8.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

String temp;

if(flag==0)

{

value1=value1+8;

temp=value1;

}

else

{

value2=value2+8;

temp=value2;

}

text.setText(temp);

}

});

final JButton button9=new JButton("9");

c.add(button9);

button9.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

String temp;

if(flag==0)

{

value1=value1+9;

temp=value1;

}

else

{

value2=value2+9;

temp=value2;

}

text.setText(temp);

}

});

final JButton button0=new JButton("0");

c.add(button0);

button0.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

String temp;

if(flag==0)

{

value1=value1+0;

temp=value1;

}

else

{

value2=value2+0;

temp=value2;

}

text.setText(temp);

}

});

final JButton buttonadd=new JButton(" + ");

c.add(buttonadd);

buttonadd.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

flag=1;

fix=1;

flagsum=0;

}

});

final JButton buttonsubtract=new JButton(" - ");

c.add(buttonsubtract);

buttonsubtract.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

flag=1;

fix=2;

flagsum=0;

}

});

final JButton buttoncheng=new JButton(" * ");

c.add(buttoncheng);

buttoncheng.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

flag=1;

fix=3;

flagsum=0;

}

});

final JButton buttonchu=new JButton(" / ");

c.add(buttonchu);

buttonchu.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

flag=1;

flagsum=0;

fix=4;

}

});

final JButton buttonequal=new JButton(" = ");

c.add(buttonequal);

buttonequal.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

double temp1,temp2;

double temp=0;

flagsum=0;

temp1=Double.parseDouble(value1);

temp2=Double.parseDouble(value2);

flag=0;

switch(fix)

{

case 1: temp=temp1+temp2;break;

case 2: temp=temp1-temp2;break;

case 3: temp=temp1*temp2;break;

case 4: temp=temp1/temp2;break;

}

result=Double.valueOf(temp).toString();

value1=result;

value2="";

flag=1;

text.setText(result);

}

});

final JButton buttonpoint=new JButton(".");

c.add(buttonpoint);

buttonpoint.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{ if(flagsum==0)

{

String temp;

if(flag==0 )

{

value1=value1+".";

temp=value1;

}

else

{

value2=value2+".";

temp=value2;

}

flagsum=1;

text.setText(temp);

}

}

});

JButton buttonz=new JButton("Start");

c.add(buttonz);

buttonz.addMouseListener(new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{ if(sum%2==1)

{

happy=true;

text.setText("0.");

flag=0;

}

else

{

happy=false;

value1="";

value2="";

text.setText("");

}

text.setEnabled(happy);

button1.setEnabled(happy);

button2.setEnabled(happy);

button3.setEnabled(happy);

button4.setEnabled(happy);

button5.setEnabled(happy);

button6.setEnabled(happy);

button7.setEnabled(happy);

button8.setEnabled(happy);

button9.setEnabled(happy);

button0.setEnabled(happy);

buttonx.setEnabled(happy);

buttony.setEnabled(happy);

buttonadd.setEnabled(happy);

buttonsubtract.setEnabled(happy);

buttonpoint.setEnabled(happy);

buttonequal.setEnabled(happy);

buttoncheng.setEnabled(happy);

buttonchu.setEnabled(happy);

sum++;

}

});

button1.setEnabled(false);

button2.setEnabled(false);

button3.setEnabled(false);

button4.setEnabled(false);

button5.setEnabled(false);

button6.setEnabled(false);

button7.setEnabled(false);

button8.setEnabled(false);

button9.setEnabled(false);

button0.setEnabled(false);

buttonx.setEnabled(false);

buttony.setEnabled(false);

buttonadd.setEnabled(false);

buttonsubtract.setEnabled(false);

buttonpoint.setEnabled(false);

buttonequal.setEnabled(false);

buttoncheng.setEnabled(false);

buttonchu.setEnabled(false);

text.setEnabled(false);

text.setBounds(20, 20, 200, 40);

buttonx.setBounds(20, 60,100, 40);

buttony.setBounds(140, 60,100, 40);

buttonz.setBounds(260, 60,80, 40);

button1.setBounds(20, 120,60, 40);

button2.setBounds(100, 120,60, 40);

button3.setBounds(180, 120,60, 40);

buttonadd.setBounds(260, 120,60, 40);

button4.setBounds(20, 180,60, 40);

button5.setBounds(100, 180,60, 40);

button6.setBounds(180, 180,60, 40);

buttonsubtract.setBounds(260, 180,60, 40);

button7.setBounds(20, 240,60, 40);

button8.setBounds(100, 240,60, 40);

button9.setBounds(180, 240,60, 40);

buttoncheng.setBounds(260,240,60,40);

button0.setBounds(20, 300,60, 40);

buttonpoint.setBounds(100, 300, 60, 40);

buttonequal.setBounds(180,300,60, 40);

buttonchu.setBounds(260, 300,60, 40);

setVisible(true);

}

class MYMouseEvent extends MouseAdapter

{

public void mousePressed(MouseEvent e)

{

value1=e.toString();

text.setText(value1);

}

}

}

class Calutator

{

public static void main(String[] args)

{

new ConstructFrame();

}

}

你自己慢慢的看吧！

java：哪里能看到JDK的源代码？

你安装JDK的目录下，有个src.zip文件，这个就是JDK源代码的java文件。

你可以解压来查看，但，最好是关联到IDE如 eclipse 中（不需解压），然后 CTRL + 点击就可以查看到源代码了。

如下图：