java常用用代码

时间:2022-06-27 16:30:10
/**
*Java获取IP代码
*/
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.net.InetAddress;
import java.net.UnknownHostException;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField; public class ip extends JFrame
implements ActionListener
{
private static final long serialVersionUID = 3339481369781127417L;
JButton jb1;
JButton jb2;
JButton jb3;
JPanel jp;
JLabel jl;
JLabel jl1;
JTextField jt; public ip()
{
this.jp = new JPanel();
this.jl = new JLabel();
this.jl1 = new JLabel("您的域名:");
this.jb1 = new JButton("提交");
this.jb2 = new JButton("重置");
this.jb3 = new JButton("退出");
this.jt = new JTextField(20);
this.jb1.addActionListener(this);
this.jb2.addActionListener(this);
this.jb3.addActionListener(this);
this.jp.setLayout(new GridLayout(3, 2));
this.jp.add(this.jl1);
this.jp.add(this.jt);
this.jp.add(this.jb1);
this.jp.add(this.jl);
this.jp.add(this.jb2);
this.jp.add(this.jb3); setBounds(200, 200, 500, 240);
add(this.jp);
setVisible(true);
setDefaultCloseOperation(3);
} public static void main(String[] args)
{
new ip();
} public void actionPerformed(ActionEvent e) {
if (e.getSource() == this.jb1) {
String url = this.jt.getText();
InetAddress ip = null;
try {
ip = InetAddress.getByName(url);
}
catch (UnknownHostException e1) {
e1.printStackTrace();
}
this.jl.setText(ip.toString());
}
else if (e.getSource() == this.jb2) {
this.jl.setText("");
this.jt.setText("");
} else {
System.exit(0);
}
}
}
/**
* 人民币转成大写
*
* @param value
* @return String
*/
public static String hangeToBig(double value)
{
char[] hunit = { '拾', '佰', '仟' }; // 段内位置表示
char[] vunit = { '万', '亿' }; // 段名表示
char[] digit = { '零', '壹', '贰', '叁', '肆', '伍', '陆', '柒', '捌', '玖' }; // 数字表示
long midVal = (long) (value * 100); // 转化成整形
String valStr = String.valueOf(midVal); // 转化成字符串 String head = valStr.substring(0, valStr.length() - 2); // 取整数部分
String rail = valStr.substring(valStr.length() - 2); // 取小数部分 String prefix = ""; // 整数部分转化的结果
String suffix = ""; // 小数部分转化的结果
// 处理小数点后面的数
if (rail.equals("00"))
{ // 如果小数部分为0
suffix = "整";
}
else
{
suffix = digit[rail.charAt(0) - '0'] + "角" + digit[rail.charAt(1) - '0'] + "分"; // 否则把角分转化出来
}
// 处理小数点前面的数
char[] chDig = head.toCharArray(); // 把整数部分转化成字符数组
char zero = '0'; // 标志'0'表示出现过0
byte zeroSerNum = 0; // 连续出现0的次数
for (int i = 0; i < chDig.length; i++)
{ // 循环处理每个数字
int idx = (chDig.length - i - 1) % 4; // 取段内位置
int vidx = (chDig.length - i - 1) / 4; // 取段位置
if (chDig[i] == '0')
{ // 如果当前字符是0
zeroSerNum++; // 连续0次数递增
if (zero == '0')
{ // 标志
zero = digit[0];
}
else if (idx == 0 && vidx > 0 && zeroSerNum < 4)
{
prefix += vunit[vidx - 1];
zero = '0';
}
continue;
}
zeroSerNum = 0; // 连续0次数清零
if (zero != '0')
{ // 如果标志不为0,则加上,例如万,亿什么的
prefix += zero;
zero = '0';
}
prefix += digit[chDig[i] - '0']; // 转化该数字表示
if (idx > 0)
prefix += hunit[idx - 1];
if (idx == 0 && vidx > 0)
{
prefix += vunit[vidx - 1]; // 段结束位置应该加上段名如万,亿
}
} if (prefix.length() > 0)
prefix += '圆'; // 如果整数部分存在,则有圆的字样
return prefix + suffix; // 返回正确表示
}
//哈弗曼编码的实现类
public class HffmanCoding {
private int charsAndWeight[][];// [][0]是 字符,[][1]存放的是字符的权值(次数)
private int hfmcoding[][];// 存放哈弗曼树
private int i = 0;// 循环变量
private String hcs[]; public HffmanCoding(int[][] chars) {
// TODO 构造方法
charsAndWeight = new int[chars.length][2];
charsAndWeight = chars;
hfmcoding = new int[2 * chars.length - 1][4];// 为哈弗曼树分配空间
} // 哈弗曼树的实现
public void coding() {
int n = charsAndWeight.length;
if (n == 0)
return;
int m = 2 * n - 1;
// 初始化哈弗曼树
for (i = 0; i < n; i++) {
hfmcoding[i][0] = charsAndWeight[i][1];// 初始化哈弗曼树的权值
hfmcoding[i][1] = 0;// 初始化哈弗曼树的根节点
hfmcoding[i][2] = 0;// 初始化哈弗曼树的左孩子
hfmcoding[i][3] = 0;// 初始化哈弗曼树的右孩子
}
for (i = n; i < m; i++) {
hfmcoding[i][0] = 0;// 初始化哈弗曼树的权值
hfmcoding[i][1] = 0;// 初始化哈弗曼树的根节点
hfmcoding[i][2] = 0;// 初始化哈弗曼树的左孩子
hfmcoding[i][3] = 0;// 初始化哈弗曼树的右孩子
} // 构建哈弗曼树
for (i = n; i < m; i++) {
int s1[] = select(i);// 在哈弗曼树中查找双亲为零的 weight最小的节点
hfmcoding[s1[0]][1] = i;// 为哈弗曼树最小值付双亲
hfmcoding[s1[1]][1] = i;
hfmcoding[i][2] = s1[0];// 新节点的左孩子
hfmcoding[i][3] = s1[1];// 新节点的右孩子
hfmcoding[i][0] = hfmcoding[s1[0]][0] + hfmcoding[s1[1]][0];// 新节点的权值是左右孩子的权值之和
} } // 查找双亲为零的 weight最小的节点
private int[] select(int w) {
// TODO Auto-generated method stub
int s[] = { -1, -1 }, j = 0;// s1 最小权值且双亲为零的节点的序号 , i 是循环变量
int min1 = 32767, min2 = 32767;
for (j = 0; j < w; j++) {
if (hfmcoding[j][1] == 0) {// 只在尚未构造二叉树的结点中查找(双亲为零的节点)
if (hfmcoding[j][0] < min1) {
min2 = min1;
s[1] = s[0];
min1 = hfmcoding[j][0];
s[0] = j; } else if (hfmcoding[j][0] < min2) {
min2 = hfmcoding[j][0];
s[1] = j;
}
}
} return s;
} public String[] CreateHCode() {// 根据哈夫曼树求哈夫曼编码
int n = charsAndWeight.length;
int i, f, c;
String hcodeString = "";
hcs = new String[n];
for (i = 0; i < n; i++) {// 根据哈夫曼树求哈夫曼编码
c = i;
hcodeString = "";
f = hfmcoding[i][1]; // f 哈弗曼树的根节点
while (f != 0) {// 循序直到树根结点
if (hfmcoding[f][2] == c) {// 处理左孩子结点
hcodeString += "0";
} else {
hcodeString += "1";
}
c = f;
f = hfmcoding[f][1];
}
hcs[i] = new String(new StringBuffer(hcodeString).reverse());
}
return hcs;
} public String show(String s) {// 对字符串显示编码
String textString = "";
char c[];
int k = -1;
c = new char[s.length()];
c = s.toCharArray();// 将字符串转化为字符数组
for (int i = 0; i < c.length; i++) {
k = c[i];
for (int j = 0; j < charsAndWeight.length; j++)
if (k == charsAndWeight[j][0])
textString += hcs[j];
}
return textString; } // 哈弗曼编码反编译
public String reCoding(String s) { String text = "";// 存放反编译后的字符
int k = 0, m = hfmcoding.length - 1;// 从根节点开始查询
char c[];
c = new char[s.length()];
c = s.toCharArray();
k = m;
for (int i = 0; i < c.length; i++) {
if (c[i] == '0') {
k = hfmcoding[k][2];// k的值为根节点左孩子的序号
if (hfmcoding[k][2] == 0 && hfmcoding[k][3] == 0)// 判断是不是叶子节点,条件(左右孩子都为零)
{
text += (char) charsAndWeight[k][0];
k = m;
}
}
if (c[i] == '1') {
k = hfmcoding[k][3];// k的值为根节点右孩子的序号
if (hfmcoding[k][2] == 0 && hfmcoding[k][3] == 0)// 判断是不是叶子节点,条件(左右孩子都为零)
{
text += (char) charsAndWeight[k][0];
k = m;
} }
}
return text;
}
}
//java各种数据库连接
//MySQL:
String Driver="com.mysql.jdbc.Driver"; //驱动程序
String URL="jdbc:mysql://localhost:3306/db_name"; //连接的URL,db_name为数据库名
String Username="username"; //用户名
String Password="password"; //密码
Class.forName(Driver).new Instance();
Connection con=DriverManager.getConnection(URL,Username,Password);
Microsoft SQL Server 2.0驱动(3个jar的那个):
String Driver="com.microsoft.jdbc.sqlserver.SQLServerDriver"; //连接SQL数据库的方法
String URL="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=db_name"; //db_name为数据库名
String Username="username"; //用户名
String Password="password"; //密码
Class.forName(Driver).new Instance(); //加载数据可驱动
Connection con=DriverManager.getConnection(URL,UserName,Password); //
Microsoft SQL Server 3.0驱动(1个jar的那个): // 老紫竹完善
String Driver="com.microsoft.sqlserver.jdbc.SQLServerDriver"; //连接SQL数据库的方法
String URL="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=db_name"; //db_name为数据库名
String Username="username"; //用户名
String Password="password"; //密码
Class.forName(Driver).new Instance(); //加载数据可驱动
Connection con=DriverManager.getConnection(URL,UserName,Password); //
Sysbase:
String Driver="com.sybase.jdbc.SybDriver"; //驱动程序
String URL="jdbc:Sysbase://localhost:5007/db_name"; //db_name为数据可名
String Username="username"; //用户名
String Password="password"; //密码
Class.forName(Driver).newInstance();
Connection con=DriverManager.getConnection(URL,Username,Password);
Oracle(用thin模式):
String Driver="oracle.jdbc.driver.OracleDriver"; //连接数据库的方法
String URL="jdbc:oracle:thin:@loaclhost:1521:orcl"; //orcl为数据库的SID
String Username="username"; //用户名
String Password="password"; //密码
Class.forName(Driver).newInstance(); //加载数据库驱动
Connection con=DriverManager.getConnection(URL,Username,Password);
PostgreSQL:
String Driver="org.postgresql.Driver"; //连接数据库的方法
String URL="jdbc:postgresql://localhost/db_name"; //db_name为数据可名
String Username="username"; //用户名
String Password="password"; //密码
Class.forName(Driver).newInstance();
Connection con=DriverManager.getConnection(URL,Username,Password);
DB2:
String Driver="com.ibm.db2.jdbc.app.DB2.Driver"; //连接具有DB2客户端的Provider实例
//String Driver="com.ibm.db2.jdbc.net.DB2.Driver"; //连接不具有DB2客户端的Provider实例
String URL="jdbc:db2://localhost:5000/db_name"; //db_name为数据可名
String Username="username"; //用户名
String Password="password"; //密码
Class.forName(Driver).newInstance();
Connection con=DriverManager.getConnection(URL,Username,Password);
Informix:
String Driver="com.informix.jdbc.IfxDriver";
String URL="jdbc:Informix-sqli://localhost:1533/db_name:INFORMIXSER=myserver"; //db_name为数据可名
String Username="username"; //用户名
String Password="password"; //密码
Class.forName(Driver).newInstance();
Connection con=DriverManager.getConnection(URL,Username,Password);
JDBC-ODBC:
String Driver="sun.jdbc.odbc.JdbcOdbcDriver";
String URL="jdbc:odbc:dbsource"; //dbsource为数据源名
String Username="username"; //用户名
String Password="password"; //密码
Class.forName(Driver).newInstance();
Connection con=DriverManager.getConnection(URL,Username,Password);
//点到线段的最短距离

private double pointToLine(int x1, int y1, int x2, int y2, int x0,
int y0) {
double space = 0;
double a, b, c;
a = lineSpace(x1, y1, x2, y2);// 线段的长度
b = lineSpace(x1, y1, x0, y0);// (x1,y1)到点的距离
c = lineSpace(x2, y2, x0, y0);// (x2,y2)到点的距离
if (c <= 0.000001 || b <= 0.000001) {
space = 0;
return space;
}
if (a <= 0.000001) {
space = b;
return space;
}
if (c * c >= a * a + b * b) {
space = b;
return space;
}
if (b * b >= a * a + c * c) {
space = c;
return space;
}
double p = (a + b + c) / 2;// 半周长
double s = Math.sqrt(p * (p - a) * (p - b) * (p - c));// 海伦公式求面积
space = 2 * s / a;// 返回点到线的距离(利用三角形面积公式求高)
return space;
} // 计算两点之间的距离
private double lineSpace(int x1, int y1, int x2, int y2) {
double lineLength = 0;
lineLength = Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2)
* (y1 - y2));
return lineLength; }
//java系统托盘的应用

package com.msg;   

import java.applet.Applet;
import java.applet.AudioClip;
import java.awt.AWTException;
import java.awt.Image;
import java.awt.MenuItem;
import java.awt.PopupMenu;
import java.awt.SystemTray;
import java.awt.TextArea;
import java.awt.TrayIcon;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Date; import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException; import org.jvnet.substance.skin.SubstanceBusinessBlueSteelLookAndFeel; /**
*
* 创建闪动的托盘图像
* @author Everest
*
*/
public class BickerTray extends JFrame implements Runnable { private static final long serialVersionUID = -3115128552716619277L; private SystemTray sysTray;// 当前操作系统的托盘对象
private TrayIcon trayIcon;// 当前对象的托盘 private ImageIcon icon = null;
private TextArea ta = null; private static int count = 1; //记录消息闪动的次数
private boolean flag = false; //是否有新消息
private static int times = 1; //接收消息次数 public BickerTray() {
this.createTrayIcon();// 创建托盘对象
Image image = this.getToolkit().getImage(getRes("com/img/f32.gif"));
this.setIconImage(image);
init();
} public URL getRes(String str){
return this.getClass().getClassLoader().getResource(str);
} /**
* 初始化窗体的方法
*/
public void init() {
this.setTitle("消息盒子");
ta = new TextArea("");
ta.setEditable(false);
this.add(ta);
this.setSize(400, 400);
//this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
// 添加窗口最小化事件,将托盘添加到操作系统的托盘
/*this.addWindowListener(new WindowAdapter() {
public void windowIconified(WindowEvent e) {
addTrayIcon();
}
});*/
addTrayIcon();
this.setVisible(true);
} /**
* 添加托盘的方法
*/
public void addTrayIcon() {
try {
sysTray.add(trayIcon);// 将托盘添加到操作系统的托盘
setVisible(false); // 使得当前的窗口隐藏
new Thread(this).start();
} catch (AWTException e1) {
e1.printStackTrace();
}
} /**
* 创建系统托盘的对象 步骤:
* 1,获得当前操作系统的托盘对象
* 2,创建弹出菜单popupMenu
* 3,创建托盘图标icon
* 4,创建系统的托盘对象trayIcon
*/
public void createTrayIcon() {
sysTray = SystemTray.getSystemTray();// 获得当前操作系统的托盘对象
icon = new ImageIcon(getRes("com/img/f17.gif"));// 托盘图标
PopupMenu popupMenu = new PopupMenu();// 弹出菜单
MenuItem mi = new MenuItem("打开");
MenuItem exit = new MenuItem("退出");
popupMenu.add(mi);
popupMenu.add(exit);
// 为弹出菜单项添加事件
mi.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ta.setText(ta.getText()+"\n==============================================\n 《通知》 今天下午4:00到大礼堂开会。 \n 第"+times+"次接收时间:"+ new Date().toLocaleString()); // 设置通知消息内容
BickerTray.this.setExtendedState(JFrame.NORMAL);
BickerTray.this.setVisible(true); // 显示窗口
BickerTray.this.toFront(); //显示窗口到最前端
flag = false; //消息打开了
count = 0; times++;
}
});
exit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
trayIcon = new TrayIcon(icon.getImage(), "消息盒子", popupMenu);
/** 添加鼠标监听器,当鼠标在托盘图标上双击时,默认显示窗口 */
trayIcon.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
if (e.getClickCount() == 2) { // 鼠标双击
ta.setText(ta.getText()+"\n==============================================\n 《通知》 今天下午4:00到大礼堂开会。 \n 第"+times+"次接收时间:"+ new Date().toLocaleString()); // 设置通知消息内容
BickerTray.this.setExtendedState(JFrame.NORMAL);
BickerTray.this.setVisible(true); // 显示窗口
BickerTray.this.toFront();
flag = false; //消息打开了
count = 0; times++;
}
}
});
} /**
* 线程控制闪动
*/
public void run() {
while (true) {
if(flag){ // 有新消息
try {
if(count == 1){
// 播放消息提示音
//AudioPlayer p = new AudioPlayer(getRes("file:com/sound/Msg.wav"));
//p.play(); p.stop();
try {
AudioClip p = Applet.newAudioClip(new URL("file:sound/msg.wav"));
p.play();
} catch (MalformedURLException e) {
e.printStackTrace();
}
}
// 闪动消息的空白时间
this.trayIcon.setImage(new ImageIcon("").getImage());
Thread.sleep(500);
// 闪动消息的提示图片
this.trayIcon.setImage(icon.getImage());
Thread.sleep(500);
} catch (Exception e) {
e.printStackTrace();
}
count++;
}else{ // 无消息或是消息已经打开过
this.trayIcon.setImage(icon.getImage());
try {
Thread.sleep(20000);
flag = true;
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
} /**
* @param args
*/
public static void main(String[] args) {
JFrame.setDefaultLookAndFeelDecorated(true);
try {
UIManager.setLookAndFeel(new SubstanceBusinessBlueSteelLookAndFeel());
} catch (UnsupportedLookAndFeelException e) {
e.printStackTrace();
} SwingUtilities.invokeLater(new Runnable() {
public void run() {
new BickerTray();
}
});
} }
//java dos输入输出

import java.util.*;
public class DaoXu { /**
* @param args
*/
public static void main(String[] args) {
// TODO 自动生成方法存根
System.out.println("请输入单个字符并回车: ");
Scanner c = new Scanner(System.in); String[] ch = new String[5]; for(int i=0; i<5; i++){
ch[i] = c.next();
} //Arrays.sort(ch); System.out.print("倒序输出: ");
for (int j = ch.length-1; j >= 0; j--) {
System.out.print(ch[j]+" ");
}
}
}
//java日期处理bean

import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.regex.Pattern; import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory; public class DateUtil {
protected static Log logger = LogFactory.getLog(DateUtil.class); // 格式:年-月-日 小时:分钟:秒
public static final String FORMAT_ONE = "yyyy-MM-dd HH:mm:ss"; // 格式:年-月-日 小时:分钟
public static final String FORMAT_TWO = "yyyy-MM-dd HH:mm"; // 格式:年月日 小时分钟秒
public static final String FORMAT_THREE = "yyyyMMdd-HHmmss"; // 格式:年-月-日
public static final String LONG_DATE_FORMAT = "yyyy-MM-dd"; // 格式:月-日
public static final String SHORT_DATE_FORMAT = "MM-dd"; // 格式:小时:分钟:秒
public static final String LONG_TIME_FORMAT = "HH:mm:ss"; //格式:年-月
public static final String MONTG_DATE_FORMAT = "yyyy-MM"; // 年的加减
public static final int SUB_YEAR = Calendar.YEAR; // 月加减
public static final int SUB_MONTH = Calendar.MONTH; // 天的加减
public static final int SUB_DAY = Calendar.DATE; // 小时的加减
public static final int SUB_HOUR = Calendar.HOUR; // 分钟的加减
public static final int SUB_MINUTE = Calendar.MINUTE; // 秒的加减
public static final int SUB_SECOND = Calendar.SECOND; static final String dayNames[] = { "星期日", "星期一", "星期二", "星期三", "星期四",
"星期五", "星期六" }; @SuppressWarnings("unused")
private static final SimpleDateFormat timeFormat = new SimpleDateFormat(
"yyyy-MM-dd HH:mm:ss"); public DateUtil() {
} /**
* 把符合日期格式的字符串转换为日期类型
*/
public static java.util.Date stringtoDate(String dateStr, String format) {
Date d = null;
SimpleDateFormat formater = new SimpleDateFormat(format);
try {
formater.setLenient(false);
d = formater.parse(dateStr);
} catch (Exception e) {
// log.error(e);
d = null;
}
return d;
} /**
* 把符合日期格式的字符串转换为日期类型
*/
public static java.util.Date stringtoDate(String dateStr, String format,
ParsePosition pos) {
Date d = null;
SimpleDateFormat formater = new SimpleDateFormat(format);
try {
formater.setLenient(false);
d = formater.parse(dateStr, pos);
} catch (Exception e) {
d = null;
}
return d;
} /**
* 把日期转换为字符串
*/
public static String dateToString(java.util.Date date, String format) {
String result = "";
SimpleDateFormat formater = new SimpleDateFormat(format);
try {
result = formater.format(date);
} catch (Exception e) {
// log.error(e);
}
return result;
} /**
* 获取当前时间的指定格式
*/
public static String getCurrDate(String format) {
return dateToString(new Date(), format);
} public static String dateSub(int dateKind, String dateStr, int amount) {
Date date = stringtoDate(dateStr, FORMAT_ONE);
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
calendar.add(dateKind, amount);
return dateToString(calendar.getTime(), FORMAT_ONE);
} /**
* 两个日期相减
* @return 相减得到的秒数
*/
public static long timeSub(String firstTime, String secTime) {
long first = stringtoDate(firstTime, FORMAT_ONE).getTime();
long second = stringtoDate(secTime, FORMAT_ONE).getTime();
return (second - first) / 1000;
} /**
* 获得某月的天数
*/
public static int getDaysOfMonth(String year, String month) {
int days = 0;
if (month.equals("1") || month.equals("3") || month.equals("5")
|| month.equals("7") || month.equals("8") || month.equals("10")
|| month.equals("12")) {
days = 31;
} else if (month.equals("4") || month.equals("6") || month.equals("9")
|| month.equals("11")) {
days = 30;
} else {
if ((Integer.parseInt(year) % 4 == 0 && Integer.parseInt(year) % 100 != 0)
|| Integer.parseInt(year) % 400 == 0) {
days = 29;
} else {
days = 28;
}
} return days;
} /**
* 获取某年某月的天数
*/
public static int getDaysOfMonth(int year, int month) {
Calendar calendar = Calendar.getInstance();
calendar.set(year, month - 1, 1);
return calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
} /**
* 获得当前日期
*/
public static int getToday() {
Calendar calendar = Calendar.getInstance();
return calendar.get(Calendar.DATE);
} /**
* 获得当前月份
*/
public static int getToMonth() {
Calendar calendar = Calendar.getInstance();
return calendar.get(Calendar.MONTH) + 1;
} /**
* 获得当前年份
*/
public static int getToYear() {
Calendar calendar = Calendar.getInstance();
return calendar.get(Calendar.YEAR);
} /**
* 返回日期的天
*/
public static int getDay(Date date) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
return calendar.get(Calendar.DATE);
} /**
* 返回日期的年
*/
public static int getYear(Date date) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
return calendar.get(Calendar.YEAR);
} /**
* 返回日期的月份,1-12
*/
public static int getMonth(Date date) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
return calendar.get(Calendar.MONTH) + 1;
} /**
* 计算两个日期相差的天数,如果date2 > date1 返回正数,否则返回负数
*/
public static long dayDiff(Date date1, Date date2) {
return (date2.getTime() - date1.getTime()) / 86400000;
} /**
* 比较两个日期的年差
*/
public static int yearDiff(String before, String after) {
Date beforeDay = stringtoDate(before, LONG_DATE_FORMAT);
Date afterDay = stringtoDate(after, LONG_DATE_FORMAT);
return getYear(afterDay) - getYear(beforeDay);
} /**
* 比较指定日期与当前日期的差
*/
public static int yearDiffCurr(String after) {
Date beforeDay = new Date();
Date afterDay = stringtoDate(after, LONG_DATE_FORMAT);
return getYear(beforeDay) - getYear(afterDay);
} /**
* 比较指定日期与当前日期的差
*/
public static long dayDiffCurr(String before) {
Date currDate = DateUtil.stringtoDate(currDay(), LONG_DATE_FORMAT);
Date beforeDate = stringtoDate(before, LONG_DATE_FORMAT);
return (currDate.getTime() - beforeDate.getTime()) / 86400000; } /**
* 获取每月的第一周
*/
public static int getFirstWeekdayOfMonth(int year, int month) {
Calendar c = Calendar.getInstance();
c.setFirstDayOfWeek(Calendar.SATURDAY); // 星期天为第一天
c.set(year, month - 1, 1);
return c.get(Calendar.DAY_OF_WEEK);
}
/**
* 获取每月的最后一周
*/
public static int getLastWeekdayOfMonth(int year, int month) {
Calendar c = Calendar.getInstance();
c.setFirstDayOfWeek(Calendar.SATURDAY); // 星期天为第一天
c.set(year, month - 1, getDaysOfMonth(year, month));
return c.get(Calendar.DAY_OF_WEEK);
} /**
* 获得当前日期字符串,格式"yyyy_MM_dd_HH_mm_ss"
*
* @return
*/
public static String getCurrent() {
Calendar cal = Calendar.getInstance();
cal.setTime(new Date());
int year = cal.get(Calendar.YEAR);
int month = cal.get(Calendar.MONTH) + 1;
int day = cal.get(Calendar.DAY_OF_MONTH);
int hour = cal.get(Calendar.HOUR_OF_DAY);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
StringBuffer sb = new StringBuffer();
sb.append(year).append("_").append(StringUtil.addzero(month, 2))
.append("_").append(StringUtil.addzero(day, 2)).append("_")
.append(StringUtil.addzero(hour, 2)).append("_").append(
StringUtil.addzero(minute, 2)).append("_").append(
StringUtil.addzero(second, 2));
return sb.toString();
} /**
* 获得当前日期字符串,格式"yyyy-MM-dd HH:mm:ss"
*
* @return
*/
public static String getNow() {
Calendar today = Calendar.getInstance();
return dateToString(today.getTime(), FORMAT_ONE);
} /**
* 判断日期是否有效,包括闰年的情况
*
* @param date
* YYYY-mm-dd
* @return
*/
public static boolean isDate(String date) {
StringBuffer reg = new StringBuffer(
"^((\\d{2}(([02468][048])|([13579][26]))-?((((0?");
reg.append("[13578])|(1[02]))-?((0?[1-9])|([1-2][0-9])|(3[01])))");
reg.append("|(((0?[469])|(11))-?((0?[1-9])|([1-2][0-9])|(30)))|");
reg.append("(0?2-?((0?[1-9])|([1-2][0-9])))))|(\\d{2}(([02468][12");
reg.append("35679])|([13579][01345789]))-?((((0?[13578])|(1[02]))");
reg.append("-?((0?[1-9])|([1-2][0-9])|(3[01])))|(((0?[469])|(11))");
reg.append("-?((0?[1-9])|([1-2][0-9])|(30)))|(0?2-?((0?[");
reg.append("1-9])|(1[0-9])|(2[0-8]))))))");
Pattern p = Pattern.compile(reg.toString());
return p.matcher(date).matches();
}
//java访问资源文件

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Properties; public class PropertyEditor {
public static void main(String[] args) throws Exception {
Properties prop = new Properties();// 属性集合对象
FileInputStream fis = new FileInputStream("prop.properties");// 属性文件输入流 (相对于根目录下的文件名,要加上包名 “src/prop.properties”)
prop.load(fis);// 将属性文件流装载到Properties对象中
fis.close();// 关闭流 // 获取属性值,sitename已在文件中定义
System.out.println("获取属性值:sitename=" + prop.getProperty("sitename"));
// 获取属性值,country未在文件中定义,将在此程序中返回一个默认值,但并不修改属性文件
System.out.println("获取属性值:country=" + prop.getProperty("country", "中国")); // 修改sitename的属性值
prop.setProperty("sitename", "中国");
// 添加一个新的属性studio
prop.setProperty("studio", "Boxcode Studio");
// 文件输出流
FileOutputStream fos = new FileOutputStream("prop.properties");
// 将Properties集合保存到流中
prop.store(fos, "Copyright (c) Boxcode Studio");
fos.close();// 关闭流
}
}
//java自定义按钮外观

import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.UIManager;
import javax.swing.plaf.synth.SynthLookAndFeel; public class MyButton {
JFrame frame = new JFrame("Test Buttons");
JButton jButton = new JButton("JButton"); // 按钮
public MyButton() {
frame.setLayout(new FlowLayout());
frame.getContentPane().add(jButton);
}
public void show() {
frame.pack();
frame.show();
}
public static void main(String[] args) {
MyButton tb = new MyButton();
tb.show();
SynthLookAndFeel slf = new SynthLookAndFeel();
try {
slf.load(MyButton.class.getResourceAsStream("mybutton.xml"), MyButton.class);
UIManager.setLookAndFeel(slf);
} catch (Exception e) {
e.printStackTrace();
return;
} }
}
//java   jdbc数据库连接

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties; public class JDBConnection {
public Connection conn = null; // 声明Connection对象的实例
public Statement stmt = null; // 声明Statement对象的实例
public ResultSet rs = null; // 声明ResultSet对象的实例 private static String dbClassName = "com.microsoft.jdbc.sqlserver.SQLServerDriver";//定义保存数据库驱动的变量
private static String dbUrl = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=DB_ATM";
private static String dbUser = "sa";
private static String dbPwd = "sa"; public JDBConnection(String propertyFileName) {// 带属性文件名的构造方法
Properties prop = new Properties();// 属性集合对象
InputStream is = null;
try {
is = JDBConnection.class.getClassLoader().getResourceAsStream(
propertyFileName);// 属性文件输入流
// is = new FileInputStream("src/" + propertyFileName);
prop.load(is);// 将属性文件流装载到Properties对象中
is.close();// 关闭流
dbClassName = prop.getProperty("dbClassName");
dbUrl = prop.getProperty("dbUrl");
dbUser = prop.getProperty("dbUser");
dbPwd = prop.getProperty("dbPwd");
} catch (Exception e) {
System.out.println("属性文件 " + propertyFileName + " 打开失败!");
}
try { Class.forName(dbClassName);// 1.注册驱动
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
} public JDBConnection() {// 默认的不带参数的构造函数
try { Class.forName(dbClassName);// 1.注册驱动
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
} public static Connection getConnection() {
Connection conn = null;
try {
// Class.forName(dbClassName);// 1.注册驱动
conn = DriverManager.getConnection(dbUrl, dbUser, dbPwd);//2.建立与数据库的链接
} catch (Exception ee) {
ee.printStackTrace();
}
if (conn == null) {
System.err
.println("警告: DbConnectionManager.getConnection() 获得数据库链接失败.\r\n\r\n链接类型:"
+ dbClassName
+ "\r\n链接位置:"
+ dbUrl
+ "\r\n用户/密码"
+ dbUser + "/" + dbPwd);
}
return conn;
} /*
* 功能:执行查询语句
*/
public ResultSet executeQuery(String sql) {
try { // 捕捉异常
conn = getConnection(); // 调用getConnection()方法构造Connection对象的一个实例conn
stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,//3.创建语句
ResultSet.CONCUR_READ_ONLY);
rs = stmt.executeQuery(sql);//4.执行查询
} catch (SQLException ex) {
System.err.println(ex.getMessage()); // 输出异常信息
}
return rs; // 返回结果集对象 5.结果处理
} /*
* 功能:执行更新操作
*/
public int executeUpdate(String sql) {
int result = 0; // 定义保存返回值的变量
try { // 捕捉异常
conn = getConnection(); // 调用getConnection()方法构造Connection对象的一个实例conn
stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
result = stmt.executeUpdate(sql); // 执行更新操作
} catch (SQLException ex) {
result = 0; // 将保存返回值的变量赋值为0
}
return result; // 返回保存返回值的变量
} /*
* 功能:关闭数据库的连接
*/
public void close() {//6.释放资源
try { // 捕捉异常
try {
if (rs != null) { // 当ResultSet对象的实例rs不为空时
rs.close(); // 关闭ResultSet对象
}
} finally {
try {
if (stmt != null) { // 当Statement对象的实例stmt不为空时
stmt.close(); // 关闭Statement对象
}
} finally {
if (conn != null) { // 当Connection对象的实例conn不为空时
conn.close(); // 关闭Connection对象
}
}
}
} catch (Exception e) {
e.printStackTrace(System.err); // 输出异常信息
}
} }
//java访问xml文件

import java.io.*;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList; public class xmljava
{ public static void main(String args[])
{
Element element=null;
File f =new File("a.xml");
DocumentBuilder db=null; //documentBuilder为抽象不能直接实例化(将XML文件转换为DOM文件)
DocumentBuilderFactory dbf=null;
try{ dbf= DocumentBuilderFactory.newInstance(); //返回documentBuilderFactory对象
db =dbf.newDocumentBuilder();//返回db对象用documentBuilderFatory对象获得返回documentBuildr对象 Document dt= db.parse(f); //得到一个DOM并返回给document对象
element = dt.getDocumentElement();//得到一个elment根元素 System.out.println("根元素:"+element.getNodeName()); //获得根节点 NodeList childNodes =element.getChildNodes() ; // 获得根元素下的子节点 for (int i = 0; i < childNodes.getLength(); i++) // 遍历这些子节点 {
Node node1 = childNodes.item(i); // childNodes.item(i); 获得每个对应位置i的结点 if ("Account".equals(node1.getNodeName()))
{
// 如果节点的名称为"Account",则输出Account元素属性type
System.out.println("\r\n找到一篇账号. 所属区域: " + node1.getAttributes().getNamedItem ("type").getNodeValue() + ". ");
NodeList nodeDetail = node1.getChildNodes(); // 获得<Accounts>下的节点
for (int j = 0; j < nodeDetail.getLength(); j++)
{ // 遍历<Accounts>下的节点
Node detail = nodeDetail.item(j); // 获得<Accounts>元素每一个节点
if ("code".equals(detail.getNodeName())) // 输出code
System.out.println("卡号: " + detail.getTextContent());
else if ("pass".equals(detail.getNodeName())) // 输出pass
System.out.println("密码: " + detail.getTextContent());
else if ("name".equals(detail.getNodeName())) // 输出name
System.out.println("姓名: " + detail.getTextContent());
else if ("money".equals(detail.getNodeName())) // 输出money
System.out.println("余额: "+ detail.getTextContent()); }
} }
} catch(Exception e){System.out.println(e);} }
} //XML CODE FILE <?xml version="1.0" encoding="gbk"?>
<Accounts>
<Account type="by0003">
<code>100001</code>
<pass>123</pass>
<name>李四</name>
<money>1000000.00</money>
</Account>
<Account type="hz0001">
<code>100002</code>
<pass>123</pass>
<name>张三</name>
<money>1000.00</money>
</Account>
</Accounts>