package com.huaye.odyandroidstore.utils; /** * <pre> * author: Blankj * blog : http://blankj.com * time : 2016/8/16 * desc : 字符串相关工具类 * </pre> */ public class StringUtils { private StringUtils() { throw new UnsupportedOperationException("u can't instantiate me..."); } /** * 判断字符串是否为null或长度为0 * * @param s 待校验字符串 * @return {@code true}: 空<br> {@code false}: 不为空 */ public static boolean isEmpty(CharSequence s) { return s == null || s.length() == 0; } /** * 判断字符串是否为null或全为空格 * * @param s 待校验字符串 * @return {@code true}: null或全空格<br> {@code false}: 不为null且不全空格 */ public static boolean isSpace(String s) { return (s == null || s.trim().length() == 0); } /** * 判断两字符串是否相等 * * @param a 待校验字符串a * @param b 待校验字符串b * @return {@code true}: 相等<br>{@code false}: 不相等 */ public static boolean equals(CharSequence a, CharSequence b) { if (a == b) return true; int length; if (a != null && b != null && (length = a.length()) == b.length()) { if (a instanceof String && b instanceof String) { return a.equals(b); } else { for (int i = 0; i < length; i++) { if (a.charAt(i) != b.charAt(i)) return false; } return true; } } return false; } /** * 判断两字符串忽略大小写是否相等 * * @param a 待校验字符串a * @param b 待校验字符串b * @return {@code true}: 相等<br>{@code false}: 不相等 */ public static boolean equalsIgnoreCase(String a, String b) { return (a == b) || (b != null) && (a.length() == b.length()) && a.regionMatches(true, 0, b, 0, b.length()); } /** * null转为长度为0的字符串 * * @param s 待转字符串 * @return s为null转为长度为0字符串,否则不改变 */ public static String null2Length0(String s) { return s == null ? "" : s; } /** * 返回字符串长度 * * @param s 字符串 * @return null返回0,其他返回自身长度 */ public static int length(CharSequence s) { return s == null ? 0 : s.length(); } /** * 首字母大写 * * @param s 待转字符串 * @return 首字母大写字符串 */ public static String upperFirstLetter(String s) { if (isEmpty(s) || !Character.isLowerCase(s.charAt(0))) return s; return String.valueOf((char) (s.charAt(0) - 32)) + s.substring(1); } /** * 首字母小写 * * @param s 待转字符串 * @return 首字母小写字符串 */ public static String lowerFirstLetter(String s) { if (isEmpty(s) || !Character.isUpperCase(s.charAt(0))) return s; return String.valueOf((char) (s.charAt(0) + 32)) + s.substring(1); } /** * 反转字符串 * * @param s 待反转字符串 * @return 反转字符串 */ public static String reverse(String s) { int len = length(s); if (len <= 1) return s; int mid = len >> 1; char[] chars = s.toCharArray(); char c; for (int i = 0; i < mid; ++i) { c = chars[i]; chars[i] = chars[len - i - 1]; chars[len - i - 1] = c; } return new String(chars); } /** * 转化为半角字符 * * @param s 待转字符串 * @return 半角字符串 */ public static String toDBC(String s) { if (isEmpty(s)) return s; char[] chars = s.toCharArray(); for (int i = 0, len = chars.length; i < len; i++) { if (chars[i] == 12288) { chars[i] = ' '; } else if (65281 <= chars[i] && chars[i] <= 65374) { chars[i] = (char) (chars[i] - 65248); } else { chars[i] = chars[i]; } } return new String(chars); } /** * 转化为全角字符 * * @param s 待转字符串 * @return 全角字符串 */ public static String toSBC(String s) { if (isEmpty(s)) return s; char[] chars = s.toCharArray(); for (int i = 0, len = chars.length; i < len; i++) { if (chars[i] == ' ') { chars[i] = (char) 12288; } else if (33 <= chars[i] && chars[i] <= 126) { chars[i] = (char) (chars[i] + 65248); } else { chars[i] = chars[i]; } } return new String(chars); } }