/** * 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
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[] 分割后的字符串数组 */ @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()); } al.add(str); return (String[]) al.toArray(new String[0]); } /** * 替换字符串 * * @param from String 原始字符串 * @param to String 目标字符串 * @param source String 母字符串 * @return String 替换后的字符串 */ 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(); } /** * 替换字符串，能能够在HTML页面上直接显示(替换双引号和小于号) * * @param str String 原始字符串 * @return String 替换后的字符串 */ public static String htmlencode(String str) { if (str == null) { return null; } return replace("/"", """, replace("<", "<", str)); } /** * 替换字符串，将被编码的转换成原始码（替换成双引号和小于号） * * @param str String * @return String */ public static String htmldecode(String str) { if (str == null) { return null; } return replace(""", "/"", replace("<", "<", str)); } private static final String _BR = "<br/>"; /** * 在页面上直接显示文本内容，替换小于号，空格，回车，TAB * * @param str String 原始字符串 * @return String 替换后的字符串 */ public static String htmlshow(String str) { if (str == null) { return null; } str = replace("<", "<", str); str = replace(" ", " ", str); str = replace("/r/n", _BR, str); str = replace("/n", _BR, str); str = replace("/t", " ", str); return str; } /** * 返回指定字节长度的字符串 * * @param str String 字符串 * @param length int 指定长度 * @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(); } /** * 判断是否为整数 * * @param str 传入的字符串 * @return 是整数返回true,否则返回false */ public static boolean isInteger(String str) { Pattern pattern = Pattern.compile("^[-//+]?[//d]*$"); return pattern.matcher(str).matches(); } /** * 判断是否为浮点数，包括double和float * * @param str 传入的字符串 * @return 是浮点数返回true,否则返回false */ public static boolean isDouble(String str) { Pattern pattern = Pattern.compile("^[-//+]?[.//d]*$"); return pattern.matcher(str).matches(); } /** * 判断输入的字符串是否符合Email样式. * * @param str 传入的字符串 * @return 是Email样式返回true,否则返回false */ public static boolean isEmail(String str) { Pattern pattern = Pattern.compile("^//w+([-+.]//w+)*@//w+([-.]//w+)*//.//w+([-.]//w+)*$"); return pattern.matcher(str).matches(); } /** * 判断输入的字符串是否为纯汉字 * * @param str 传入的字符窜 * @return 如果是纯汉字返回true,否则返回false */ public static boolean isChinese(String str) { Pattern pattern = Pattern.compile("[/u0391-/uFFE5]+$"); return pattern.matcher(str).matches(); } /** * 是否为空白,包括null和"" * * @param str * @return */ public static boolean isBlank(String str) { return str == null || str.trim().length() == 0; } /** * 判断是否为质数 * * @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 = { "中国", "1中国", "中国1", "1中国2", "中1国" }; for (String str : chineses) { System.out.println(str + "=" + isChinese(str)); } }}
