Java常見幫助類（2）字串處理類
阿新 • • 發佈：2019-02-01
閒話少說，下面幫組類主要是實現字串判空，字串相等，字串替換，字串填補等十幾個功能，具體看程式碼：
/** * 字串處理類 * * */ public class StringUtil { /** * 判斷字串是否為空 * * @param str * @return */ public static boolean isBlank(String str) { int strLen; if (str == null || (strLen = str.length()) == 0) return true; for (int i = 0; i < strLen; i++) if (!Character.isWhitespace(str.charAt(i))) return false; return true; } public static boolean isNotBlank(String str) { return !isBlank(str); } public static boolean isEmpty(String str) { return str == null || str.length() == 0; } public static boolean isNotEmpty(String str) { return !isEmpty(str); } /** * 以type為分界符分離str字串,返回分離後的陣列 * * @param str * 待處理字串 * @param type * 分界符 * * @return array 處理後的字串陣列 */ public static String[] split(String str, String type) { int begin = 0; int pos = 0; String tempstr = ""; String[] array = null; Vector vec = null; int len = str.trim().length(); str = str + type; if (len > 0) { while (str.length() > 0) { if (vec == null) { vec = new Vector(); } pos = str.indexOf(type, begin); tempstr = str.substring(begin, pos); str = str.substring(pos + 1, str.length()); vec.add(tempstr); } } else { vec = new Vector(); vec.add(""); } if (vec != null) { array = new String[vec.size()]; for (int i = 0; i < vec.size(); i++) { array[i] = (String) vec.get(i); } } else { array = new String[0]; } return array; } /** * 按長度把字串前補0 * * @param s * 需要補位字串物件 * @return len 該字串的長度 */ public static String len(String s, int len) { if (!notNull(s)) s = ""; int length = len - s.length(); for (int i = 0; i < length; i++) { s = "0" + s; } return s; } /** * 判斷字串是否為空 * * * @param s * 需要判斷字串物件 * @return true 表示不為空 false 為空 * @throws java.lang.Exception */ public static boolean notNull(String s) { if (s == null || s.trim().length() <= 0 || "".equals(s) || "null".equals(s)) return false; else return true; } /** * 返回一個布林值，表示兩個字串是否相等 * * * @param objstr * 字串物件 * * @param bjstr * 字串物件 * * @return false 表示不相等 true 相等 * @throws java.lang.Exception */ public static boolean equals(String objstr, String bjstr) { boolean lean = false; lean = (objstr != null) && objstr.equals(bjstr); return lean; } /** * 替換source中的str1為str2 * * @param source * 待替換的字串 * * @param str1 * 待替換的字元 * @param str2 * 替換的字元 * * @return java.lang.String 替換後的字串 */ public static String replace(String source, char str1, String str2) { return replace(source, String.valueOf(str1), str2); } /** * 替換掉source字串中的所有需要替換的字元 * * @param source * @param str1 * @param str * @return */ public static String replaceSome(String source, String... str) { String sourcestr = source; for (String replicestr : str) { sourcestr = replace(sourcestr, String.valueOf(replicestr), ""); } return sourcestr; } /** * 替換source中的str1為str2 * * @param source * 待替換的字串 * * @param str1 * 待替換的字元 * @param str2 * 替換的字元 * * @return java.lang.String 替換後的字串 */ public static String replace(String source, String str1, String str2) { if (source == null) return ""; String desc = ""; int posstart = 0; int posend = source.indexOf(str1, 0); int len = source.length(); while (posend >= 0 && posstart < len) { desc += source.substring(posstart, posend) + str2; posstart = posend + str1.length(); posend = source.indexOf(str1, posstart); } if (posstart < len) desc += source.substring(posstart, len); return desc; } /** * 替換source中的"\n"為"換行符" * * @param source * 待替換的字串 * * @return java.lang.String 替換後的字串 */ public static String replace(String content) { String[] tempValue = null; if (content != null) { if (content.indexOf("\n") != -1) { tempValue = StringUtil.split(content, "\n"); } if (tempValue != null && tempValue.length > 0) { content = ""; for (int i = 0; i < tempValue.length; i++) { content += tempValue[i] + "<br>"; } content = content.substring(0, content.length() - 4); } } return content; } /** * 將字串列表轉換成字串陣列 * * @param list * List 字串列表 * * @return String[] */ public static String[] list2Array(List list) { String[] strs = new String[list.size()]; for (int i = 0; i < strs.length; i++) { strs[i] = (String) list.get(i); } return strs; } /** * 將字串陣列轉換成字串列表 * * @param array * String[] array 字串陣列 * * @return List 字串列表 */ public static List array2List(String[] array) { List list = null; if (array != null) { list = new ArrayList(array.length); for (int i = 0; i < array.length; i++) { list.add(list.get(i)); } } return list; } /** * 過濾Html的特殊字元 */ public static String htmlEscape(String in) { StringBuffer out = new StringBuffer(); for (int i = 0; i < in.length(); i++) { char c = in.charAt(i); switch (c) { case '"': out.append("""); break; case '&': out.append("&"); break; case '<': out.append("<"); break; case '>': out.append(">"); break; default: out.append(c); break; } } return out.toString(); } /** * 取String最後幾位 */ public static String getStrLast(String str, int i) { return str.substring(str.length() - i, str.length()); } /** * 判斷是該字串是否是圖片或者是圖片連線 jpg,bmp,gif,jpeg */ public static boolean isImage(String str) { boolean flag = false; String type1 = StringUtil.getStrLast(str, 4); if (type1.equals(".jpg") || type1.equals(".JPG")) { flag = true; } if (type1.equals(".bmp") || type1.equals(".BMP")) { flag = true; } if (type1.equals(".gif") || type1.equals(".GIF")) { flag = true; } String type2 = StringUtil.getStrLast(str, 5); if (type2.equals(".jpeg") || type2.equals(".GPEG")) { flag = true; } return flag; } public static String urlFilter(String str) { String temp = "http://www."; String temp1 = "www."; String temp2 = "http://"; if (str.indexOf(temp) > -1) { } else { if (str.indexOf(temp2) > -1) { } else { if (str.indexOf(temp1) > -1) { str = "http://" + str; } else { str = temp2 + str; } } } String s = str.substring(7); if (s.indexOf("/") > 0) { } else { char c = str.charAt(str.length() - 1); if ("/".equals(String.valueOf(c))) { } else { str = str + "/"; } } return str; } public static String rssUrlEcode(String rss) { if (isBlank(rss)) { return ""; } String re = ""; try { re = java.net.URLEncoder.encode("\"" + rss + "\"", "utf-8"); } catch (UnsupportedEncodingException e) { System.out.println("轉碼異常,UnsupportedEncodingException"); e.printStackTrace(); } return re; } /** * Replaces the first substring of this string that matches the given key * with the given replacement. * * @param str * The String to be replaced * @param key * Key within the String to be searched and replaced * @param replacement * The String used to replace * @return The String with the first occurence of the key value replaced. */ public static String replaceFirst(String str, String key, String replacement) { StringBuffer result = new StringBuffer(str); int pos = str.indexOf(key); if (pos >= 0) { result.replace(pos, pos + key.length(), replacement); // System.out.println( "result = " + result ); } return result.toString(); } public static String replaceChar(String str) { return str.replace("\\", "/"); } /** * 對double資料進行取精度. * <p> * For example: <br> * double value = 100.345678; <br> * double ret = round(value,4,BigDecimal.ROUND_HALF_UP); <br> * ret為100.3457 <br> * * @param value * double資料. * @param scale * 精度位數(保留的小數位數). * @param roundingMode * 精度取值方式. * @return 精度計算後的資料. */ public static double round(double value, int scale, int roundingMode) { BigDecimal bd = new BigDecimal(value); bd = bd.setScale(scale, roundingMode); double d = bd.doubleValue(); bd = null; return d; } /** * 得到檔名的字尾 * * @param args */ public static String getHouzhui(String string) { int t = string.lastIndexOf("."); String str = string.substring(t + 1); return str; } /** * 擷取字串作為檔案標題 */ public static String getTitleSubString(String str) { Pattern p = Pattern.compile("\\s*|\t*|\r*|\n*"); Matcher m = p.matcher(str); String after = m.replaceAll(""); String temp = after.replaceAll("\\p{P}", ""); return temp.substring(0, 10).trim(); } // 得到字串裡的大寫個數 public static int getUpperCaseNum(String str) { int count = 0; Pattern p = Pattern.compile("[A-Z]"); Matcher m = p.matcher(str); while (m.find()) { count++; } return count; } // 得到字串裡的小寫個數 public static int getLowerCaseNum(String str) { int count = 0; Pattern p = Pattern.compile("[a-z]"); Matcher m = p.matcher(str); while (m.find()) { count++; } return count; } // 得到字串裡的數字個數 public static int getFigureNum(String str) { int count = 0; Pattern p = Pattern.compile("\\d"); Matcher m = p.matcher(str); while (m.find()) { count++; } return count; } // 得到字串裡特殊字元個數 public static int getSpecialCharNum(String str) { int count = 0; Pattern p = Pattern.compile("[\\W_]"); Matcher m = p.matcher(str); while (m.find()) { count++; } return count; } // 去掉最後一個字元 public static String removeLastChar(String str) { if (str != "") { str = str.substring(0, str.length() - 1); } return str; } /** * 去除重複項 * * @param list * @return list */ public static List removeDuplicateWithOrder(List list) { Set set = new HashSet(); List newList = new ArrayList(); for (Iterator iter = list.iterator(); iter.hasNext();) { Object element = iter.next(); if (set.add(element)) newList.add(element); } return newList; } /** * 位元組轉換成字串以兆的形式顯示 * * @param size * @return */ public static String formate(int size) { StringBuffer sb = new StringBuffer(); sb.append(String.valueOf((int) (size / 1024))); sb.append("M"); return sb.toString(); } /** * 根據stringSource包含的字元與number生成固定長度的隨機字串 * * @param number * @param stringSource * @return */ public static String getFixedSizeRandomStr(int length, String stringSource) { Random random = new Random(); StringBuffer sBuffer = new StringBuffer(); if (length > 0) { for (int i = 0; i < length; i++) { int number = random.nextInt(stringSource.length()); sBuffer.append(stringSource.charAt(number)); } } return sBuffer.toString(); } /* * * 格式化數字 */ public static String formatNumber(Object number, String pattern) { String numberFormated = ""; if (number != null) { try { numberFormated = new DecimalFormat(pattern).format(number); } catch (Exception e) { e.printStackTrace(); } } return numberFormated; } /** * 得到某個字串標記的前面字串 */ public static String getHeadWord(String str, String mark) { int markNum = str.indexOf(mark); String newWord = str.substring(0, markNum); return newWord; } public static void main(String[] args) { /* * String temp = "www.replays.net"; String temp1 = "replays.net"; * * String str = StringUtil.urlFilter(temp); System.out.println(str); * String st1r = StringUtil.urlFilter(temp1); System.out.println(st1r); * * // System.out.println(temp.indexOf("http://d")); * System.out.println(rssUrlEcode("行動通訊")); * System.out.println(rssUrlEcode("移動")); * System.out.println(rssUrlEcode("www")); * System.out.println(rssUrlEcode("aaaaaaaaa")); */ System.out.println(replaceSome("abcdefgh", "a", "b", "c")); } /** * * @描述: 轉換url 去掉 http:// 和 https:// * */ public static String formatUrl(String url) { if (StringUtils.isBlank(url)) { return ""; } if (url.startsWith("https://")) { url = url.substring(8); } else if (url.startsWith("http://")) { url = url.substring(7); } return url; } }