java常用函数2VIP免费

/** * 将某个日期以固定格式转化成字符串 * * @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; } /** * 判断任意一个整数是否素数 * * @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; } /** * 获得任意一个整数的阶乘，递归 * * @param n * @return n! */ public static int factorial(int n) { if (n == 1) { return 1; } return n * factorial(n - 1); } /** * 将指定 byte 数组以 16 进制的形式打印到控制台 * * @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(""); } wait(); //线程等待 notify(); //激活一个线程/* * Db.javaCreated 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 ...