字符串相关→StringUtils

	/**
	* <pre>
	* author: Blankj
	* blog : http://blankj.com
	* time : 2016/8/16
	* desc : 字符串相关工具类
	* </pre>
	*/
	public final 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 isTrimEmpty(String s) {
	return (s == null || s.trim().length() == 0);
	}
	/**
	* 判断字符串是否为null或全为空白字符
	*
	* @param s 待校验字符串
	* @return {@code true}: null或全空白字符<br> {@code false}: 不为null且不全空白字符
	*/
	public static boolean isSpace(String s) {
	if (s == null) return true;
	for (int i = 0, len = s.length(); i < len; ++i) {
	if (!Character.isWhitespace(s.charAt(i))) {
	return false;
	}
	}
	return true;
	}
	/**
	* 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);
	}
	}