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com.emily.infrastructure.common.StringUtils Maven / Gradle / Ivy
package com.emily.infrastructure.common;
import com.emily.infrastructure.common.charset.Charsets;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.Arrays;
/**
* 字符串操作工具类
*
* @author Emily
* @since Created in 2023/6/4 2:13 PM
*/
public class StringUtils {
/**
* 空格字符串
*/
public static final String SPACE = " ";
/**
* 空字符串
*/
public static final String EMPTY = "";
/**
* 首字母转大写
* ----------------------------------------------
* 示例程序：
*
* {@code
* Assert.assertEquals(StrUtils.toUpperFirstCase(null), null);
* Assert.assertEquals(StrUtils.toUpperFirstCase(""), "");
* Assert.assertEquals(StrUtils.toUpperFirstCase(" "), " ");
* Assert.assertEquals(StrUtils.toUpperFirstCase(" a".trim()), "A");
* Assert.assertEquals(StrUtils.toUpperFirstCase("a"), "A");
* Assert.assertEquals(StrUtils.toUpperFirstCase("abc"), "Abc");
* }
*
* ----------------------------------------------
*
* @param str 字符串
* @return 转换后的字符串
*/
public static String toUpperFirstCase(String str) {
if (str == null || str.length() == 0) {
return str;
}
if (str.length() == 1) {
return str.toUpperCase();
}
return String.valueOf(str.charAt(0)).toUpperCase().concat(str.substring(1));
}
/**
* 将字符串首字母转为小写
* ---------------------------------------------
*
* {@code
* Assert.assertEquals(StrUtils.toLowerFirstCase(null), null);
* Assert.assertEquals(StrUtils.toLowerFirstCase(""), "");
* Assert.assertEquals(StrUtils.toLowerFirstCase(" "), " ");
* Assert.assertEquals(StrUtils.toLowerFirstCase(" A"), " A");
* Assert.assertEquals(StrUtils.toLowerFirstCase("A"), "a");
* Assert.assertEquals(StrUtils.toLowerFirstCase("Abc"), "abc");
* }
*
* ---------------------------------------------
*
* @param str 字符串
* @return 转换后的字符串
*/
public static String toLowerFirstCase(String str) {
if (str == null || str.length() == 0) {
return str;
}
if (str.length() == 1) {
return str.toLowerCase();
}
return String.valueOf(str.charAt(0)).toLowerCase().concat(str.substring(1));
}
/**
* 判断字符串是否为空
* ----------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertTrue(StrUtils.isEmpty(null));
* Assert.assertTrue(StrUtils.isEmpty(""));
* Assert.assertFalse(StrUtils.isEmpty("a"));
* Assert.assertFalse(StrUtils.isEmpty(" a"));
* Assert.assertFalse(StrUtils.isEmpty(" a "));
* }
*
* ----------------------------------------------------------
*
* @param cs 字符串
* @return true-为空 false-不为空
*/
public static boolean isEmpty(final CharSequence cs) {
return cs == null || cs.length() == 0;
}
/**
* 判断字符串是否不为空
* -------------------------------------------------
* 示例
*
* {@code
* Assert.assertFalse(StrUtils.isNotEmpty(null));
* Assert.assertFalse(StrUtils.isNotEmpty(""));
* Assert.assertTrue(StrUtils.isNotEmpty("a"));
* Assert.assertTrue(StrUtils.isNotEmpty(" a"));
* Assert.assertTrue(StrUtils.isNotEmpty(" a "));
* }
*
* -------------------------------------------------
*
* @param cs 字符串
* @return true-不为空 false-为空
*/
public static boolean isNotEmpty(final CharSequence cs) {
return !isEmpty(cs);
}
/**
* 判定字符串是否是空白
* ---------------------------------------------------------
*
* {@code
* Assert.assertEquals(StringUtils.isBlank(null), true);
* Assert.assertEquals(StringUtils.isBlank(""), true);
* Assert.assertEquals(StringUtils.isBlank(" "), true);
* Assert.assertEquals(StringUtils.isBlank(" a"), false);
* Assert.assertEquals(StringUtils.isBlank(" a "), false);
* }
*
* ---------------------------------------------------------
*
* @param cs 字符串
* @return true-空白 false-不是空白
*/
public static boolean isBlank(final CharSequence cs) {
final int strLen = length(cs);
if (strLen == 0) {
return true;
}
for (int i = 0; i < strLen; i++) {
if (!Character.isWhitespace(cs.charAt(i))) {
return false;
}
}
return true;
}
/**
* 判定字符串是是非空白
* -----------------------------------------------------
*
* {@code
* Assert.assertEquals(StringUtils.isNotBlank(null), false);
* Assert.assertEquals(StringUtils.isNotBlank(""), false);
* Assert.assertEquals(StringUtils.isNotBlank(" "), false);
* Assert.assertEquals(StringUtils.isNotBlank(" a"), true);
* Assert.assertEquals(StringUtils.isNotBlank(" a "), true);
* }
*
* -----------------------------------------------------
*
* @param cs 字符串
* @return true-非空白 false-空白
*/
public static boolean isNotBlank(final CharSequence cs) {
return !isBlank(cs);
}
/**
* 如果字符串为null或者空字符串，则返回默认字符串
* -----------------------------------------------------
* 示例：
*
* {@code
* Assert.assertEquals(StringUtils.defaultIfEmpty(null, "ab"),"ab");
* Assert.assertEquals(StringUtils.defaultIfEmpty("", "ab"),"ab");
* Assert.assertEquals(StringUtils.defaultIfEmpty(" ", "ab")," ");
* Assert.assertEquals(StringUtils.defaultIfEmpty("1", "ab"),"1");
* }
*
* -----------------------------------------------------
*
* @param str 字符串
* @param defaultStr 默认字符串
* @param 字符类型
* @return 最终结果
*/
public static T defaultIfEmpty(final T str, final T defaultStr) {
return isEmpty(str) ? defaultStr : str;
}
/**
* 如果字符串为nul，则返回defaultStr字符串
* -------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertEquals(StringUtils.defaultString(null, "ab"), "ab");
* Assert.assertEquals(StringUtils.defaultString("", "ab"), "");
* Assert.assertEquals(StringUtils.defaultString("1", "ab"), "1");
* }
*
* -------------------------------------------------------
*
* @param str 字符串
* @param defaultStr 默认字符串
* @param 字符类型
* @return 最终字符串结果
*/
public static T defaultString(final T str, final T defaultStr) {
return str == null ? defaultStr : str;
}
/**
* 如果字符为null、""、" "，则返回默认字符串
* ------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertEquals(StringUtils.defaultIfBlank(null, "ab"),"ab");
* Assert.assertEquals(StringUtils.defaultIfBlank("", "ab"),"ab");
* Assert.assertEquals(StringUtils.defaultIfBlank(" ", "ab"),"ab");
* Assert.assertEquals(StringUtils.defaultIfBlank("1", "ab"),"1");
* }
*
* ------------------------------------------------------
*
* @param str 字符串
* @param defaultStr 默认字符串
* @param 字符类型
* @return 最终结果
*/
public static T defaultIfBlank(final T str, final T defaultStr) {
return isBlank(str) ? defaultStr : str;
}
/**
* 字符串左侧拼接指定的字符达到指定的长度
* ------------------------------------------------------------
* 实例如下：
*
* {@code
* Assert.assertEquals(StrUtils.leftPad(null, 5, 'a'), null);
* Assert.assertEquals(StrUtils.leftPad("", 5, '0'), "00000");
* Assert.assertEquals(StrUtils.leftPad("aaaaa", 5, '0'), "aaaaa");
* Assert.assertEquals(StrUtils.leftPad("2", 5, '0'), "00002");
* }
*
* ------------------------------------------------------------
*
* @param str 字符串
* @param size 字符串总长度
* @param padChar 要拼接的字符
* @return 拼接后的字符串
*/
public static String leftPad(final String str, final int size, final char padChar) {
if (str == null) {
return null;
}
final int pads = size - str.length();
if (pads <= 0) {
return str;
}
return repeat(padChar, pads).concat(str);
}
/**
* 字符串左侧拼接上指定的字符串
* --------------------------------------------------------
* 示例如下：
*
* {@code
* Assert.assertEquals(StrUtils.leftPad(null, 5, "ab"), null);
* Assert.assertEquals(StrUtils.leftPad(null, 5, null), null);
* Assert.assertEquals(StrUtils.leftPad(null, 5, ""), null);
* Assert.assertEquals(StrUtils.leftPad("", 5, ""), " ");
* Assert.assertEquals(StrUtils.leftPad("1", 5, ""), " 1");
* Assert.assertEquals(StrUtils.leftPad("1", 5, " "), " 1");
* Assert.assertEquals(StrUtils.leftPad("1", 5, "0"), "00001");
* Assert.assertEquals(StrUtils.leftPad("1", 5, "0A"), "0A0A1");
* Assert.assertEquals(StrUtils.leftPad("1", 5, "0AB"), "0AB01");
* Assert.assertEquals(StrUtils.leftPad("11", 8, "0AB"), "0AB0AB11");
* Assert.assertEquals(StrUtils.leftPad("11", 7, "0AB"), "0AB0A11");
* }
*
* --------------------------------------------------------
*
* @param str 字符串
* @param size 拼接后字符串长度
* @param padStr 要拼接的字符串
* @return 拼接后的字符串
*/
public static String leftPad(final String str, final int size, String padStr) {
if (str == null) {
return null;
}
if (isEmpty(padStr)) {
padStr = SPACE;
}
final int padLen = padStr.length();
final int strLen = str.length();
final int pads = size - strLen;
if (pads <= 0) {
return str;
}
if (pads == padLen) {
return padStr.concat(str);
} else if (pads < padLen) {
return padStr.substring(0, pads).concat(str);
} else {
final char[] padding = new char[pads];
final char[] padChars = padStr.toCharArray();
for (int i = 0; i < pads; i++) {
padding[i] = padChars[i % padLen];
}
return new String(padding).concat(str);
}
}
/**
* 字符串右侧拼接上指定的字符达到指定的长度
* -----------------------------------------------------
*
* {@code
* Assert.assertEquals(StringUtils.rightPad(null, 5, 'a'), null);
* Assert.assertEquals(StringUtils.rightPad("", 5, '0'), "00000");
* Assert.assertEquals(StringUtils.rightPad("aaaaa", 5, '0'), "aaaaa");
* Assert.assertEquals(StringUtils.rightPad("2", 5, '0'), "20000");
* }
*
* -----------------------------------------------------
*
* @param str 字符串
* @param size 拼接后字符串的总长度
* @param padChar 要拼接的字符
* @return 拼接后的字符串
*/
public static String rightPad(final String str, final int size, final char padChar) {
if (str == null) {
return null;
}
final int pads = size - str.length();
if (pads <= 0) {
return str;
}
return str.concat(repeat(padChar, pads));
}
/**
* 将字符串右侧拼接上指定的字符串达到指定的长度
* -----------------------------------------------------
*
* {@code
* Assert.assertEquals(StringUtils.rightPad(null, 5, "ab"), null);
* Assert.assertEquals(StringUtils.rightPad(null, 5, null), null);
* Assert.assertEquals(StringUtils.rightPad(null, 5, ""), null);
* Assert.assertEquals(StringUtils.rightPad("", 5, ""), " ");
* Assert.assertEquals(StringUtils.rightPad("1", 5, ""), "1 ");
* Assert.assertEquals(StringUtils.rightPad("1", 5, " "), "1 ");
* Assert.assertEquals(StringUtils.rightPad("1", 5, "0"), "10000");
* Assert.assertEquals(StringUtils.rightPad("1", 5, "0A"), "10A0A");
* Assert.assertEquals(StringUtils.rightPad("1", 5, "0AB"), "10AB0");
* Assert.assertEquals(StringUtils.rightPad("11", 8, "0AB"), "110AB0AB");
* Assert.assertEquals(StringUtils.rightPad("11", 7, "0AB"), "110AB0A");
* }
*
* -----------------------------------------------------
*
* @param str 字符串
* @param size 拼接后的长度
* @param padStr 拼接字符串
* @return 拼接后的字符串
*/
public static String rightPad(final String str, final int size, String padStr) {
if (str == null) {
return null;
}
if (isEmpty(padStr)) {
padStr = SPACE;
}
final int padLen = padStr.length();
final int strLen = str.length();
final int pads = size - strLen;
if (pads <= 0) {
return str;
}
if (pads == padLen) {
return str.concat(padStr);
} else if (pads < padLen) {
return str.concat(padStr.substring(0, pads));
} else {
final char[] padding = new char[pads];
final char[] padChars = padStr.toCharArray();
for (int i = 0; i < pads; i++) {
padding[i] = padChars[i % padLen];
}
return str.concat(new String(padding));
}
}
/**
* 将字符重复拼接N个拼接为字符串返回
*
* @param ch 字符
* @param repeat 重复个数
* @return 拼接后的字符串
*/
public static String repeat(final char ch, final int repeat) {
if (repeat <= 0) {
return EMPTY;
}
final char[] buf = new char[repeat];
Arrays.fill(buf, ch);
return new String(buf);
}
/**
* 获取字符串的长度
* ----------------------------------------------------------
*
* {@code
* Assert.assertEquals(StrUtils.length(null), 0);
* Assert.assertEquals(StrUtils.length(""), 0);
* Assert.assertEquals(StrUtils.length("12"), 2);
* }
*
* ----------------------------------------------------------
*
* @param cs 字符串，如果为null，则长度为0
* @return 字符串长度
*/
public static int length(final CharSequence cs) {
return cs == null ? 0 : cs.length();
}
/**
* 判定指定的字符串是否是数字
* -----------------------------------------------
*
* {@code
* Assert.assertFalse(StringUtils.isNumeric(null));
* Assert.assertFalse(StringUtils.isNumeric(""));
* Assert.assertFalse(StringUtils.isNumeric(" "));
* Assert.assertTrue(StringUtils.isNumeric("1"));
* Assert.assertTrue(StringUtils.isNumeric("\u0967\u0968\u0969"));
* Assert.assertFalse(StringUtils.isNumeric("1-"));
* Assert.assertFalse(StringUtils.isNumeric("+1"));
* Assert.assertFalse(StringUtils.isNumeric("-1"));
* }
*
* -----------------------------------------------
*
* @param cs 字符串
* @return true-数字 false-否
*/
public static boolean isNumeric(final CharSequence cs) {
if (isEmpty(cs)) {
return false;
}
final int len = cs.length();
for (int i = 0; i < len; i++) {
if (!Character.isDigit(cs.charAt(i))) {
return false;
}
}
return true;
}
/**
* 字符串使用指定的标识缩略
* --------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertEquals(StringUtils.abbreviate(null, "...", 8), null);
* Assert.assertEquals(StringUtils.abbreviate("", "...", 8), "");
* Assert.assertEquals(StringUtils.abbreviate("a", "...", 8), "a...");
* Assert.assertEquals(StringUtils.abbreviate("abc", "...", 8), "abc...");
* Assert.assertEquals(StringUtils.abbreviate("abcde", "...", 8), "abcde...");
* Assert.assertEquals(StringUtils.abbreviate("ABCDEFGHIJKLMN", "...", 8), "ABCDE...");
* }
*
* --------------------------------------------------------
*
* @param str 字符串
* @param abbrevMarker 缩略标识，如：...
* @param maxLength 缩略后字符串最大长度
* @return 缩略后的字符串
*/
public static String abbreviate(final String str, final String abbrevMarker, int maxLength) {
if (isEmpty(str)) {
return str;
}
int strLen = str.length();
int markerLen = abbrevMarker.length();
if (strLen + markerLen <= maxLength) {
return str.concat(abbrevMarker);
}
return str.substring(0, maxLength - markerLen).concat(abbrevMarker);
}
/**
* 判定字符串是否以指定的前缀开头
* -------------------------------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertFalse(StringUtils.startsWith(null, "ab", 0, false));
* Assert.assertFalse(StringUtils.startsWith("", "ab", 0, false));
* Assert.assertFalse(StringUtils.startsWith(null, null, 0, false));
* Assert.assertFalse(StringUtils.startsWith("", "", 0, false));
* Assert.assertTrue(StringUtils.startsWith("abcd", "ab", 0, false));
* Assert.assertTrue(StringUtils.startsWith("abcd", "ab", 0, true));
* Assert.assertFalse(StringUtils.startsWith("Abcd", "ab", 0, false));
* Assert.assertTrue(StringUtils.startsWith("Abcd", "ab", 0, true));
* Assert.assertFalse(StringUtils.startsWith("AbCd", "bc", 1, false));
* Assert.assertTrue(StringUtils.startsWith("AbCd", "bc", 1, true));
* Assert.assertFalse(StringUtils.startsWith("AbCd", "bc", 3, true));
* Assert.assertFalse(StringUtils.startsWith("AbCd", "bc", 4, true));
* }
*
* -------------------------------------------------------------------------------
*
* @param str 字符串
* @param prefix 前缀
* @param toffset 起始索引
* @param ignoreCase 是否忽略大小写
* @return true-是，false-否
*/
public static boolean startsWith(final String str, final String prefix, int toffset, final boolean ignoreCase) {
if (isEmpty(str) || isEmpty(prefix)) {
return false;
}
if (ignoreCase) {
return str.toLowerCase().startsWith(prefix.toLowerCase(), toffset);
}
return str.startsWith(prefix, toffset);
}
/**
* 判定字符串是否以指定的前缀开头
* ----------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertFalse(StringUtils.startsWith(null, null));
* Assert.assertFalse(StringUtils.startsWith(null, ""));
* Assert.assertFalse(StringUtils.startsWith(null, "a"));
* Assert.assertFalse(StringUtils.startsWith("", null));
* Assert.assertFalse(StringUtils.startsWith("", ""));
* Assert.assertTrue(StringUtils.startsWith("abb", "ab"));
* Assert.assertFalse(StringUtils.startsWith("abb", "Ab"));
* }
*
* ----------------------------------------------------------
*
* @param str 字符串
* @param prefix 前缀
* @return true-是，false-否
*/
public static boolean startsWith(final String str, final String prefix) {
return startsWith(str, prefix, 0, false);
}
/**
* 判定字符串是否以指定的前缀开头
* ----------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertFalse(StringUtils.startsWithIgnoreCase(null, null));
* Assert.assertFalse(StringUtils.startsWithIgnoreCase(null, ""));
* Assert.assertFalse(StringUtils.startsWithIgnoreCase(null, "a"));
* Assert.assertFalse(StringUtils.startsWithIgnoreCase("", null));
* Assert.assertFalse(StringUtils.startsWithIgnoreCase("", ""));
* Assert.assertTrue(StringUtils.startsWithIgnoreCase("abb", "ab"));
* Assert.assertTrue(StringUtils.startsWithIgnoreCase("abb", "Ab"));
* }
*
* ----------------------------------------------------------
*
* @param str 字符串
* @param prefix 前缀
* @return true-是，false-否
*/
public static boolean startsWithIgnoreCase(final String str, final String prefix) {
return startsWith(str, prefix, 0, true);
}
/**
* 判定字符串是否以指定后缀结尾
* -------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertFalse(StringUtils.endsWith(null, null, false));
* Assert.assertFalse(StringUtils.endsWith(null, "", false));
* Assert.assertFalse(StringUtils.endsWith("", null, false));
* Assert.assertFalse(StringUtils.endsWith("", "", false));
* Assert.assertTrue(StringUtils.endsWith("abcd", "cd", false));
* Assert.assertTrue(StringUtils.endsWith("abcd", "cD", true));
* }
*
* -------------------------------------------------------
*
* @param str 字符串
* @param suffix 前缀
* @param ignoreCase 是否忽略大小写
* @return true-是，false-否
*/
public static boolean endsWith(final String str, final String suffix, final boolean ignoreCase) {
if (isEmpty(str) || isEmpty(suffix)) {
return false;
}
if (ignoreCase) {
return str.toLowerCase().endsWith(suffix.toLowerCase());
}
return str.endsWith(suffix);
}
/**
* 判定字符串是否以指定后缀结尾
* -------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertFalse(StringUtils.endsWith(null, null));
* Assert.assertFalse(StringUtils.endsWith(null, ""));
* Assert.assertFalse(StringUtils.endsWith("", null));
* Assert.assertFalse(StringUtils.endsWith("", ""));
* Assert.assertTrue(StringUtils.endsWith("abcd", "cd"));
* Assert.assertFalse(StringUtils.endsWith("abcd", "cD"));
* }
*
* -------------------------------------------------------
*
* @param str 字符串
* @param suffix 前缀
* @return true-是，false-否
*/
public static boolean endsWith(final String str, final String suffix) {
return endsWith(str, suffix, false);
}
/**
* 判定字符串是否以指定后缀结尾
* -------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertFalse(StringUtils.endsWithIgnoreCase(null, null));
* Assert.assertFalse(StringUtils.endsWithIgnoreCase(null, ""));
* Assert.assertFalse(StringUtils.endsWithIgnoreCase("", null));
* Assert.assertFalse(StringUtils.endsWithIgnoreCase("", ""));
* Assert.assertTrue(StringUtils.endsWithIgnoreCase("abcd", "cd"));
* Assert.assertTrue(StringUtils.endsWithIgnoreCase("abcd", "cD"));
* }
*
* -------------------------------------------------------
*
* @param str 字符串
* @param suffix 前缀
* @return true-是，false-否
*/
public static boolean endsWithIgnoreCase(final String str, final String suffix) {
return endsWith(str, suffix, true);
}
/**
* 获取字符串对应的字节码数组
* ----------------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertEquals(StringUtils.getBytes(null, null).length, 0);
* Assert.assertEquals(StringUtils.getBytes("", null).length, 0);
* Assert.assertEquals(StringUtils.getBytes("ab", Charset.defaultCharset()).length, 2);
* }
*
* ----------------------------------------------------------------
*
* @param string 字符串
* @param charset 编码类型
* @return 字节数组
*/
public static byte[] getBytes(final String string, final Charset charset) {
return string == null ? ArrayUtils.EMPTY_BYTE_ARRAY : string.getBytes(Charsets.toCharset(charset));
}
/**
* 将字符串转换为字节数组
*
* @param string 字符串
* @param charset 编码名称
* @return 字节数组
* @throws UnsupportedEncodingException 不支持的编码异常
*/
public static byte[] getBytes(final String string, final String charset) throws UnsupportedEncodingException {
return string == null ? ArrayUtils.EMPTY_BYTE_ARRAY : string.getBytes(Charsets.toCharsetName(charset));
}
/**
* 字符串中的字符序列替换
* ---------------------------------------------------------
* 示例：
*
* {@code
* Assert.assertEquals(StringUtils.replace("abc", "ab", "AB"), "ABc");
* Assert.assertThrows(IllegalArgumentException.class, () -> StringUtils.replace("abc", "", ""));
* Assert.assertThrows(IllegalArgumentException.class, () -> StringUtils.replace("abc", null, ""));
* }
*
* ---------------------------------------------------------
*
* @param str 字符串
* @param target 要替换的字符值序列
* @param replacement 字符值的替换序列
* @return 替换后的字符串
*/
public static String replace(final String str, final CharSequence target, final CharSequence replacement) {
if (isEmpty(str)) {
return str;
}
if (isEmpty(target) || isEmpty(replacement)) {
throw new IllegalArgumentException("非法参数");
}
return str.replace(target, replacement);
}
/**
* 替换字符串中的指定字符
* -------------------------------------------------------------
* 示例：
* {@code
* Assert.assertEquals(StringUtils.replace("abc", 'b', 'B'), "aBc");
* }
*
* -------------------------------------------------------------
*
* @param str 字符串
* @param oldChar 要被替换的字符
* @param newChar 字符的替换字符
* @return 替换字符后的字符串
*/
public static String replace(final String str, final char oldChar, final char newChar) {
if (isEmpty(str)) {
return str;
}
return str.replace(oldChar, newChar);
}
/**
* 字符串两端空格去除，如果为null，则返回null
* --------------------------------------------------------
* 示例：
* {@code
* Assert.assertEquals(StringUtils.trim(null),null);
* Assert.assertEquals(StringUtils.trim(""),"");
* Assert.assertEquals(StringUtils.trim(" a "),"a");
* }
*
* --------------------------------------------------------
*
* @param str 字符串
* @return 去除空格后的字符串对象；
*/
public static String trim(final String str) {
return str == null ? null : str.trim();
}
/**
* 将字符串去除两端空格，如果为null,则返回空字符串""
* --------------------------------------------------------
* 示例：
* {@code
* Assert.assertEquals(StringUtils.trimToEmpty(null), "");
* Assert.assertEquals(StringUtils.trimToEmpty(""), "");
* Assert.assertEquals(StringUtils.trimToEmpty(" a "), "a");
* }
*
* --------------------------------------------------------
*
* @param str 字符串
* @return 去除空格后的字符串对象；
*/
public static String trimToEmpty(final String str) {
return str == null ? EMPTY : str.trim();
}
/**
* 将字符串去除两端空格，如果为null或"",则返回null
* --------------------------------------------------------
* 示例：
* {@code
* Assert.assertEquals(StringUtils.trimToNull(" "), null);
* Assert.assertEquals(StringUtils.trimToNull(null), null);
* Assert.assertEquals(StringUtils.trimToNull(" a "), "a");
* }
*
* --------------------------------------------------------
*
* @param str 字符串
* @return 去除空格后的字符串对象；
*/
public static String trimToNull(final String str) {
final String ts = trim(str);
return isEmpty(ts) ? null : ts;
}
/**
* 字符串分割
* -----------------------------------------------------
* 示例如下：
* {@code
* Assert.assertNotNull(StringUtils.split(null, null));
* Assert.assertNotNull(StringUtils.split("", null));
* Assert.assertEquals(StringUtils.split("abcd", "").length,4);
* Assert.assertEquals(StringUtils.split("abcd", ",").length,1);
* Assert.assertEquals(StringUtils.split("ab,cd", ",").length,2);
* Assert.assertEquals(StringUtils.split("abcd", "c").length,2);
* }
*
* -----------------------------------------------------
*
* @param str 待分割的字符串
* @param separatorChars 字符串分隔符
* @return 分割后的字符串数组
*/
public static String[] split(final String str, final String separatorChars) {
if (isBlank(str)) {
return ArrayUtils.EMPTY_STRING_ARRAY;
}
return str.split(separatorChars);
}
/**
* 字符串拼接
*
* @param strings 字符串数组
* @return 拼接后的字符串
*/
public static String join(String... strings) {
return String.join(EMPTY, strings);
}
}
