/**
     * 將某個日期以固定格式轉化成字符串
     *
     * @param date
     * @return String
     */
    public static String dateToStr(java.util.Date date)
    {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String str = sdf.format(date);
        return str;
    }
------------------------------------------------------------------------------------------
 /**
     * 判斷任意一個整數是否素數
     *
     * @param n
     * @return boolean
     */
    public static boolean isPrimes(int n)
    {
        for (int i = 2; i <= Math.sqrt(n); i++)
        {
            if (n % i == 0)
            {
                return false;
            }
        }
        return true;
    }
------------------------------------------------------------------------------------------
/**
     * 獲得任意一個整數的階乘，遞歸
      *
     * @param n
     * @return n!
     */
    public static int factorial(int n)
    {
        if (n == 1)
        {
            return 1;
        }
        return n * factorial(n - 1);
    }
--------------------------------------------------------------------------------------------
/**
     * 將指定byte數組以16進制的形式打印到控制臺
     *
     * @param hint
     *            String
     * @param b
     *            byte[]
     * @return void
     */
    public static void printHexString(String hint, byte[] b)
    {
        System.out.print(hint);
        for (int i = 0; i < b.length; i++)
        {
            String hex = Integer.toHexString(b[i] & 0xFF);
            if (hex.length() == 1)
            {
                hex = '0' + hex;
            }
            System.out.print(hex.toUpperCase() + " ");
        }
        System.out.println("");
    }

-----------------------------------------------------------------------------------------
package net.java2000.tools;

/**
 * Title:        Java Bean 工具
 * Description:
 * Copyright:    Copyright (c) 2001
 * Company:      JAVA世紀網 http://www.java2000.net
 * @author 趙學慶
 * @version 1.0
 */
import java.util.*;
import java.util.regex.Pattern;

public class StrTools {
 /**
  * 分割字符串
  *
  * @param str
  *            String 原始字符串
  * @param splitsign
  *            String 分隔符
  * @return String[] 分割后的字符串數組
  */
 @SuppressWarnings("unchecked")
 public static String[] split(String str, String splitsign) {
  int index;
  if (str == null || splitsign == null)
   return null;
  ArrayList al = new ArrayList();
  while ((index = str.indexOf(splitsign)) != -1) {
   al.add(str.substring(0, index));
   str = str.substring(index + splitsign.length());
   //System.out.println("str is : " +str);
  }
  al.add(str);
  return (String[]) al.toArray(new String[0]);
 }

 /**
  * 替換字符串
  *
  * @param from
  *            String 原始字符串
  * @param to
  *            String 目標字符串
  * @param source
  *            String 母字符串
  * @return String 替換后的字符串
  */
 public static String replace(String from, String to, String source) {
  if (source == null || from == null || to == null)
   return null;
  StringBuffer bf = new StringBuffer("");
  int index = -1;
  while ((index = source.indexOf(from)) != -1) {
   bf.append(source.substring(0, index) + to);
   source = source.substring(index + from.length());
   index = source.indexOf(from);
  }
  bf.append(source);
  return bf.toString();
 }

 /**
  * 替換字符串，能能夠在HTML頁面上直接顯示(替換雙引號和小于號)
  *
  * @param str
  *            String 原始字符串
  * @return String 替換后的字符串
  */
 public static String htmlencode(String str) {
  if (str == null) {
   return null;
  }

  return replace("\"", "&quot;", replace("<", "&lt;", str));
 }

 /**
  * 替換字符串，將被編碼的轉換成原始碼（替換成雙引號和小于號）
  *
  * @param str
  *            String
  * @return String
  */
 public static String htmldecode(String str) {
  if (str == null) {
   return null;
  }

  return replace("&quot;", "\"", replace("&lt;", "<", str));
 }

 private static final String _BR = "<br/>";

 /**
  * 在頁面上直接顯示文本內容，替換小于號，空格，回車，TAB
  *
  * @param str
  *            String 原始字符串
  * @return String 替換后的字符串
  */
 public static String htmlshow(String str) {
  if (str == null) {
   return null;
  }

  str = replace("<", "&lt;", str);
  str = replace(" ", "&nbsp;", str);
  str = replace("\r\n", _BR, str);
  str = replace("\n", _BR, str);
  str = replace("\t", "&nbsp;&nbsp;&nbsp;&nbsp;", str);
  return str;
 }

 /**
  * 返回指定字節長度的字符串
  *
  * @param str
  *            String 字符串
  * @param length
  *            int 指定長度
  * @return String 返回的字符串
  */
 public static String toLength(String str, int length) {
  if (str == null) {
   return null;
  }
  if (length <= 0) {
   return "";
  }
  try {
   if (str.getBytes("GBK").length <= length) {
    return str;
   }
  } catch (Exception ex) {
  }
  StringBuffer buff = new StringBuffer();

  int index = 0;
  char c;
  length -= 3;
  while (length > 0) {
   c = str.charAt(index);
   if (c < 128) {
    length--;
   } else {
    length--;
    length--;
   }
   buff.append(c);
   index++;
  }
  buff.append("...");
  return buff.toString();
 }

 /**
  * 判斷是否為整數
  *
  * @param str
  *            傳入的字符串
  * @return 是整數返回true,否則返回false
  */
 public static boolean isInteger(String str) {
  Pattern pattern = Pattern.compile("^[-\\+]?[\\d]*$");
  return pattern.matcher(str).matches();
 }

 /**
  * 判斷是否為浮點數，包括double和float
  *
  * @param str
  *            傳入的字符串
  * @return 是浮點數返回true,否則返回false
  */
 public static boolean isDouble(String str) {
  Pattern pattern = Pattern.compile("^[-\\+]?[.\\d]*$");
  return pattern.matcher(str).matches();
 }

 /**
  * 判斷輸入的字符串是否符合Email樣式.
  *
  * @param str
  *            傳入的字符串
  * @return 是Email樣式返回true,否則返回false
  */
 public static boolean isEmail(String str) {
  Pattern pattern = Pattern
    .compile("^\\w+([-+.]\\w+)*@\\w+([-.]\\w+)*\\.\\w+([-.]\\w+)*$");
  return pattern.matcher(str).matches();
 }

 /**
  * 判斷輸入的字符串是否為純漢字
  *
  * @param str
  *            傳入的字符竄
  * @return 如果是純漢字返回true,否則返回false
  */
 public static boolean isChinese(String str) {
  Pattern pattern = Pattern.compile("[\u0391-\uFFE5]+$");
  return pattern.matcher(str).matches();
 }

 /**
  * 是否為空白,包括null和""
  *
  * @param str
  * @return
  */
 public static boolean isBlank(String str) {
  return str == null || str.trim().length() == 0;
 }

 /**
  * 判斷是否為質數
  *
  * @param x
  * @return
  */
 public static boolean isPrime(int x) {
  if (x <= 7) {
   if (x == 2 || x == 3 || x == 5 || x == 7)
    return true;
  }
  int c = 7;
  if (x % 2 == 0)
   return false;
  if (x % 3 == 0)
   return false;
  if (x % 5 == 0)
   return false;
  int end = (int) Math.sqrt(x);
  while (c <= end) {
   if (x % c == 0) {
    return false;
   }
   c += 4;
   if (x % c == 0) {
    return false;
   }
   c += 2;
   if (x % c == 0) {
    return false;
   }
   c += 4;
   if (x % c == 0) {
    return false;
   }
   c += 2;
   if (x % c == 0) {
    return false;
   }
   c += 4;
   if (x % c == 0) {
    return false;
   }
   c += 6;
   if (x % c == 0) {
    return false;
   }
   c += 2;
   if (x % c == 0) {
    return false;
   }
   c += 6;
  }
  return true;
 }

 public static void main(String[] args) {
  String[] numbers = { "12345", "-12345", "123.45", "-123.45", ".12345",
    "-.12345", "a12345", "12345a", "123.a45" };
  for (String str : numbers) {
   System.out
     .println(str + "=" + isInteger(str) + " " + isDouble(str));
  }

  String[] emails = { "1@2.com", "1.2@3.com", "1@3.4.5.com" };
  for (String str : emails) {
   System.out.println(str + "=" + isEmail(str));
  }
  String[] chineses = { "中國", "1中國", "中國1", "1中國2", "中1國" };
  for (String str : chineses) {
   System.out.println(str + "=" + isChinese(str));
  }
   String str = "lin@san@fu@2009";
   String[] strArray =split(str,"@");
   for(String s: strArray)
   System.out.println(s);
 }
}
-------------------------------------------------------------------------------------------------
/* * Db.java
Created on 2007年8月20日, 上午 8:37
*/
import java.io.*;
import java.sql.*;
import java.util.Properties;
public class Db {
    private String driver;
    private String url;
    private String user;
    private String password;
    private Connection conn;
    private Statement stm;
    private ResultSet rs;
    public Db(){
        this("DBConf.properties");
    }
    public Db(String conf) {
        loadProperties(conf);
        setConn();
    }
    public Connection getConn(){
        return this.conn;
    }
  //handle the properties file to get the informations for connection
    private void loadProperties(String conf){
        Properties props = new Properties();
        try {
            props.load(new FileInputStream(conf));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        this.driver = props.getProperty("driver");
        this.url = props.getProperty("url");
        this.user = props.getProperty("user");
        this.password = props.getProperty("password");
    }
    //implement the Connection
    private void setConn(){
        try {
            Class.forName(driver);
            this.conn = DriverManager.getConnection(url,user,password);
        } catch(ClassNotFoundException classnotfoundexception) {
              classnotfoundexception.printStackTrace();
            System.err.println("db: " + classnotfoundexception.getMessage());
        } catch(SQLException sqlexception) {
            System.err.println("db.getconn(): " + sqlexception.getMessage());
        }
    }
       public void doInsert(String sql) {
        try {
            Statement statement = conn.createStatement();
            int i = stm.executeUpdate(sql);
        } catch(SQLException sqlexception) {
            System.err.println("db.executeInset:" + sqlexception.getMessage());
        }
    }
    public void doDelete(String sql) {
        try {
            stm = conn.createStatement();
            int i = stm.executeUpdate(sql);
        } catch(SQLException sqlexception) {
            System.err.println("db.executeDelete:" + sqlexception.getMessage());
        }
    }
    public void doUpdate(String sql) {
        try {
            stm = conn.createStatement();
            int i = stm.executeUpdate(sql);
        } catch(SQLException sqlexception) {
            System.err.println("db.executeUpdate:" + sqlexception.getMessage());
        }
    }
   
    public ResultSet doSelect(String sql) {
        try {
            stm = conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);
            rs = stm.executeQuery(sql);
        } catch(SQLException sqlexception) {
            System.err.println("db.executeQuery: " + sqlexception.getMessage());
        }
        return rs;
    }
    public static void main(String[] args){
        try{
            Db db = new Db();
            Connection conn = db.getConn();
            if(conn != null && !conn.isClosed()) {
                System.out.println("連結成功");
                ResultSet rs = db.doSelect("select * from content");
                while(rs.next()){
                    System.out.println(rs.getString(1)+":"+rs.getString(2)+":"+rs.getString(3));
                  }
                rs.close();
                conn.close();
            }
        }catch(SQLException e) {
            e.printStackTrace();
        }
    } 
}