Java常用工具类
import java.io.UnsupportedEncodingException; /** * 字符串工具类 * * @author 尘世间迷茫的小书童 * */ public class StringUtils { /** 7位ASCII字符，也叫作ISO646-US、Unicode字符集的基本拉丁块 */ public static final String US_ASCII = "US-ASCII"; /** ISO 拉丁字母表 No.1，也叫作 ISO-LATIN-1 */ public static final String ISO_8859_1 = "ISO-8859-1"; /** 8 位 UCS 转换格式 */ public static final String UTF_8 = "UTF-8"; /** 16 位 UCS 转换格式，Big Endian（最低地址存放高位字节）字节顺序 */ public static final String UTF_16BE = "UTF-16BE"; /** 16 位 UCS 转换格式，Little-endian（最高地址存放低位字节）字节顺序 */ public static final String UTF_16LE = "UTF-16LE"; /** 16 位 UCS 转换格式，字节顺序由可选的字节顺序标记来标识 */ public static final String UTF_16 = "UTF-16"; /** 中文超大字符集 */ public static final String GBK = "GBK"; /** * 判断字符串是否为空 * * @param str * @return 为空返回true */ public static boolean isEmpty(String str) { return null == str && str.length() == 0; } /** * 判断字符串是否不为空 * * @param str * @return 不为空返回true */ public static boolean isNotEmpty(String str) { return null != str && str.length() > 0; } /** * 去掉字符串两头的空字符，str为空返回null * * @param str * @return */ public static String trim(String str) { if (isEmpty(str)) return null; return str.trim(); } /** * 替换字符串 * * @param str * @param oldChar * @param newChar * @return */ public static String replace(String str, String oldChar, String newChar) { return str.replace(oldChar, newChar); } /** * 可以替换大部分空白字符， 不限于空格 * * @param str * @return */ public static String replace(String str) { return str.replaceAll("\\s*", ""); } /** * 根据start和end范围用newStr覆盖str * * @param str * @param newStr * @param start * @param end * @return */ public static String overlay(String str, String newStr, int start, int end) { char[] charArray = str.toCharArray(); char[] startArray = new char[start]; int length = charArray.length - end - 1; char[] endArray = new char[length]; for (int i = 0; i < start; i++) { startArray[i] = charArray[i]; } for (int i = 0; i < length; i++) { end++; endArray[i] = charArray[end]; } return String.valueOf(startArray) + newStr + String.valueOf(endArray); } /** * 如果str中是以start开头，则删除开头，否者返回原字符串 * * @param str * @param start * @return */ public static String removeStart(String str, String start) { int startIndex = str.indexOf(start); if (startIndex == 0) return overlay(str, "", 0, startIndex + 1); return str; } /** * 如果str中是以end结尾，则删除结尾，否者返回原字符串 * * @param str * @param end * @return */ public static String removeEnd(String str, String end) { int endIndex = str.lastIndexOf(end); if (endIndex == str.length() - end.length()) return overlay(str, "", endIndex, str.length() - 1); return str; } /** * 删除str中所有空白字符 * * @param str * @return */ public static String deleteWhitespace(String str) { return str.replace(" ", ""); } /** * 计算str1在str中出现次数 * * @param str * @param str1 * @return */ public static int countStr(String str, String str1) { if (isEmpty(str) || isEmpty(str1)) return 0; int count = 0; int position = 0; int index; while ((index = str.indexOf(str1, position)) != -1) { ++count; position = index + str1.length(); } return count; } /** * 反转字符串 * * @param str * @return */ public static String reverseStr1(String str) { return new StringBuilder(str).reverse().toString(); } /** * 反转字符串 * * @param str * @return */ public static String reverseStr2(String str) { char[] chars = str.toCharArray(); String reverse = ""; for (int i = chars.length - 1; i >= 0; i--) { reverse += chars[i]; } return reverse; } /** * 反转字符串 * * @param str * @return */ public static String reverseStr3(String str) { String reverse = ""; int length = str.length(); for (int i = 0; i < length; i++) { reverse = str.charAt(i) + reverse; } return reverse; } /** * 根据sub拆分str为数组，使用. |分割时需要加\\ * * @param str * @param sub * @return */ public static String[] split(String str, String sub) { return str.split(sub); } /** * 字符转String * * @param c * @return */ public static String charToString(char c) { return String.valueOf(c); } /** * 字符数组转String * * @param c * @return */ public static String charArrayToString(char[] c) { return String.valueOf(c); } /** * 字符数组转String * * @param c * @param start * @param end * @return */ public static String charArrayToString(char[] c, int start, int end) { return String.valueOf(c, start, end); } /** * String数组转String * * @param strs * @return */ public static String strArrayToStr(String[] strs) { StringBuffer buffer = new StringBuffer(); for (int i = 0; i < strs.length; i++) { buffer.append(strs[i]); } return buffer.toString(); } /** * 转换字符串编码格式 * * @param str * @param oldCharset * @param newCharset * @return * @throws UnsupportedEncodingException */ public static String changeCharset(String str, String oldCharset, String newCharset) throws UnsupportedEncodingException { return new String(str.getBytes(oldCharset), newCharset); } /** * 转换字符串编码格式 * * @param str * @param newCharset * @return * @throws UnsupportedEncodingException */ public static String changeCharset(String str, String newCharset) throws UnsupportedEncodingException { return new String(str.getBytes(), newCharset); } /** * 将字符编码转换成US-ASCII码 */ public String toASCII(String str) throws UnsupportedEncodingException { return changeCharset(str, US_ASCII); } /** * 将字符编码转换成ISO-8859-1码 */ public String toISO_8859_1(String str) throws UnsupportedEncodingException { return changeCharset(str, ISO_8859_1); } /** * 将字符编码转换成UTF-8码 */ public String toUTF_8(String str) throws UnsupportedEncodingException { return changeCharset(str, UTF_8); } /** * 将字符编码转换成UTF-16BE码 */ public String toUTF_16BE(String str) throws UnsupportedEncodingException { return changeCharset(str, UTF_16BE); } /** * 将字符编码转换成UTF-16LE码 */ public String toUTF_16LE(String str) throws UnsupportedEncodingException { return changeCharset(str, UTF_16LE); } /** * 将字符编码转换成UTF-16码 */ public String toUTF_16(String str) throws UnsupportedEncodingException { return changeCharset(str, UTF_16); } /** * 将字符编码转换成GBK码 */ public String toGBK(String str) throws UnsupportedEncodingException { return changeCharset(str, GBK); } public static void main(String[] args) { // String replace = replace("maxinhai", "ma", "li"); // System.out.println(replace); // String overlay = overlay("maxinhai", "li", 0, 4); // System.out.println(overlay); // String removeSatrt = removeStart("maxinhai", "ma"); // System.out.println(removeSatrt); // String removeEnd = removeEnd("maxinhai", "hai"); // System.out.println(removeEnd); // String deleteWhitespace = deleteWhitespace(" ma xin hai "); // System.out.println(deleteWhitespace); // String replace = replace(" ma xin hai\t "); // System.out.println(replace); // int countStr = countStr("121121212121211212", "1"); // System.out.println(countStr); } }
各种个工具类。。。
总结以后，方便copy
