/** * Copyright 2015-2025 FLY的狐狸(email:jflyfox@sina.com qq:369191470). * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * */ package com.jflyfox.util; import java.util.regex.Pattern; /** * 字符串处理 * * @author flyfox 2012.08.08 * @email 330627517@qq.com */ public class StrUtils { /** * 为空 * * 2013年9月8日下午10:08:44 * flyfox 330627517@qq.com * @param str * @return */ public static boolean isEmpty(String str) { return str == null || "".equals(str); } /** * 不为空 * * 2013年9月8日下午10:08:31 * flyfox 330627517@qq.com * @param str * @return */ public static boolean isNotEmpty(String str) { return !isEmpty(str); } /** * 转大写 * * 2013年9月8日下午10:08:23 * flyfox 330627517@qq.com * @param instr * @return */ public static String toUpperCase(String instr) { return instr == null ? instr : instr.toUpperCase(); } /** * 转小写 * * 2013年9月8日下午10:08:10 * flyfox 330627517@qq.com * @param instr * @return */ public static String toLowerCase(String instr) { return instr == null ? instr : instr.toLowerCase(); } /** * 首字母大写 ,其余不变 * * 2013年9月8日下午10:08:17 * flyfox 330627517@qq.com * @param str * @return */ public static String toUpperCaseFirst(String str) { if (str == null) return null; if (str.length() == 0) return str; String pre = String.valueOf(str.charAt(0)); return str.replaceFirst(pre, pre.toUpperCase()); } /** * 首字母小写 ,其余不变 * * 2013年9月8日下午10:08:17 * flyfox 330627517@qq.com * @param str * @return */ public static String toLowerCaseFirst(String str) { if (str == null) return null; if (str.length() == 0) return str; String pre = String.valueOf(str.charAt(0)); return str.replaceFirst(pre, pre.toLowerCase()); } /** * 不会抛NullPointerException 的trim()
* 传入null会返回null * * @param str * @return */ public static String trim(String str) { return str == null ? null : str.trim(); } /** * 过滤 ;当instr==null时返回长度为0的"";
* 与 nvl(...)系的区别在于只处理null ,不处理长度为0的""; * * @param instr * @return */ public static String nvl(String instr) { return nvl(instr, ""); } /** * 过滤 ,把null和长度为0的""当成同一种情况处理;
* 当instr==null||"".equals(instr)时返回defaultValue ;其它情况返回 instr * * @param instr * @param defaultValue * @return */ public static String nvl(String instr, String defaultValue) { return instr == null || "".equals(instr) ? defaultValue : instr; } /** * 比较 str1 和 str2 如果都是 null 或者 str1.equals(str2) 返回 true 表示一样 ; * * @author wangp * @since 2009.01.10 * @param str1 * @param str2 * @return */ public static boolean equals(String str1, String str2) { if (str1 == null && str2 == null) return true; if (str1 != null && str1.equals(str2)) return true; return false; } public static String apadLeft(double a, int b, int len) { return apadLeft(String.valueOf(a), String.valueOf(b), len); } public static String apadRight(double a, int b, int len) { return apadRight(String.valueOf(a), String.valueOf(b), len); } public static String apadLeft(String str, String str2, int len) { if (str == null || str.length() == len || str2 == null) return str; if (str.length() > len) return str.substring(str.length() - len, len); return apadpro(str, str2, len, true); } public static String apadRight(String str, String str2, int len) { if (str == null || str.length() == len || str2 == null) return str; if (str.length() > len) return str.substring(0, len); return apadpro(str, str2, len, false); } private static String apadpro(String a, String b, int len, boolean appendleft) { int f = len - a.length(); for (int i = 0; i < f; i++) { a = appendleft == true ? b + a : a + b; } return a; } /** * 清除字符串中所有的空格 ,传入null返回null * * @author wangp * @since 2009.02.06 * @param str * @return */ public static String clear(String str) { return clear(str, " "); } /** * 清除str中出现的所有str2字符序列直到结果中再也找不出str2为止 str2 == null时返回str * * @author wangp * @since 2009.02.06 * @param str * 原始字符串 * @param str2 * 清除的目标 * @return */ public static String clear(String str, String str2) { if (str == null) return str; if (str2 == null) return str; String reg = "(" + str2 + ")+"; Pattern p = Pattern.compile(reg); while (p.matcher(str).find()) { str = str.replaceAll(reg, ""); } return str; } /** * 如果str的长度超过了c则取c-sub.length长度,然后拼上sub结尾 * * @author wangp * @since 2009.06.11 * @param str * @param c * @param sub * @return */ public static String suojin(String str, int c, String sub) { if (isEmpty(str)) return str; if (str.length() <= c) return str; sub = nvl(sub); c = c - sub.length(); c = c > str.length() ? 0 : c; str = str.substring(0, c); return str + sub; } /** * 如果str的长度超过了length,取前length位然后拼上... * * @author yimian * @since 2009.06.11 * @param str * @param length * @return */ public static String suojin(String str, int length) { return suojin(str, length, "…"); } public static String replaceOnce(String text, String searchString, String replacement) { return replace(text, searchString, replacement, 1); } public static String replace(String text, String searchString, String replacement) { return replace(text, searchString, replacement, -1); } public static String replace(String text, String searchString, String replacement, int max) { if (isEmpty(text) || isEmpty(searchString) || replacement == null || max == 0) return text; int start = 0; int end = text.indexOf(searchString, start); if (end == -1) return text; int replLength = searchString.length(); int increase = replacement.length() - replLength; increase = increase >= 0 ? increase : 0; increase *= max >= 0 ? max <= 64 ? max : 64 : 16; StringBuffer buf = new StringBuffer(text.length() + increase); do { if (end == -1) break; buf.append(text.substring(start, end)).append(replacement); start = end + replLength; if (--max == 0) break; end = text.indexOf(searchString, start); } while (true); buf.append(text.substring(start)); return buf.toString(); } }