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package com.iwuyc.tools.commons.util.string;
import com.iwuyc.tools.commons.exception.UnsupportedException;
import com.iwuyc.tools.commons.util.collection.ArrayUtil;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.charset.UnsupportedCharsetException;
import java.util.Optional;
import java.util.StringJoiner;
/**
* @author @Neil
* @since @2017年10月15日
*/
public abstract class StringUtils {
private StringUtils() {
}
public static final String NIL_STRING = "";
public static final String EMPTY_STRING = " ";
public static final char BLANK_CHAR = ' ';
public static final String SYSTEM_NEW_LINE = System.getProperty("line.separator");
public static final String LINUX_NEW_LINE = "\n";
public static final String WINDOWS_NEW_LINE = "\r\n";
/**
* 回车
*/
public static final String CR = "\r";
/**
* 换行
*/
public static final String LF = "\n";
/**
* @param str 待判断的字符
* @return 如果字符为null或者为""空字符，则返回true，否则返回false
*/
public static boolean isEmpty(CharSequence str) {
return null == str || str.length() == 0;
}
/**
* isEmpty的取反
*
* @see StringUtils#isEmpty(CharSequence)
*/
public static boolean isNotEmpty(CharSequence str) {
return !isEmpty(str);
}
public static boolean equals(CharSequence one, CharSequence otherOne) {
if (one == null || otherOne == null) {
return one == otherOne;
}
return one.equals(otherOne);
}
public static boolean notEquals(CharSequence primaryStr, CharSequence slaveStr) {
return !equals(primaryStr, slaveStr);
}
public static String turnFirstCharToLowerCase(String source) {
if (isEmpty(source)) {
return source;
}
char firstChar = source.charAt(0);
if (firstChar < 'A' || firstChar > 'Z') {
return source;
}
firstChar = (char) (firstChar - 'A' + 'a');
return source.length() > 1 ? firstChar + source.substring(1) : String.valueOf(firstChar);
}
/**
* 判断字符串是否为空字符串
*
* ex:
* str = ""; => true
* str = " "; => true
* str = null; => true
* str = " a "; => false
*
*
* @param str 待检测的字符串
* @return 如果为空字符串，则返回true，否则返回false
*/
public static boolean isBlank(CharSequence str) {
if (isEmpty(str)) {
return true;
}
return str.chars().allMatch(item -> item == ' ');
}
/**
* 判断字符串是否为空字符串，与 {@link #isBlank(CharSequence)} 方法结果相反
*
* @param str 待检测的字符串
* @return 如果不为空字符串，则返回true，否则返回false
*/
public static boolean isNotBlank(CharSequence str) {
return !isBlank(str);
}
/**
* 计算字符串的长度
*
* @param str 待计算的字符串
* @return 返回字符串的长度，如果str为null则返回为0
*/
public static int length(String str) {
return str == null ? 0 : str.length();
}
/**
* 判断字符串数组中是否存在空的字符串 {{@link #isEmpty(CharSequence)}}
*
* @param strs 待验证的字符串数组
* @return 如果字符串数值中存在空字符串，则返回true，否则返回false
*/
public static boolean isAnyEmpty(CharSequence... strs) {
if (ArrayUtil.isEmpty(strs)) {
return true;
}
for (CharSequence str : strs) {
if (isEmpty(str)) {
return true;
}
}
return false;
}
/**
* 判断字符串数组中是否不存在空的字符串 !{@link #isAnyEmpty(CharSequence...)}
*
* @param strs 待验证的字符串数组
* @return 如果字符串数组中存在空字符串，则返回false，否则返回true
*/
public static boolean isNonEmpty(CharSequence... strs) {
return !isAnyEmpty(strs);
}
/**
* 去除字符串头尾的空白字符
*
* @param str 待去除的字符串
* @return 已去除空白字符的字符串
*/
public static String trim(String str) {
if (str == null) {
return null;
} else {
return str.trim();
}
}
/**
* 将所有非null的字符串以 delimiter 作为分隔符拼接起来，忽略为null或者为空的字符串，
* 但会拼接所有字符都是空格的字符串
*
* @param delimiter 分隔符
* @param elements 待拼接的字符串列表
* @return 拼接后的字符串，如果elements为null，或者其中的字符串列表元素都为null，则返回 {@link Optional#empty()}
*/
public static Optional joinWithoutNull(String delimiter, String... elements) {
if (ArrayUtil.isEmpty(elements)) {
return Optional.empty();
}
final StringJoiner stringJoiner = new StringJoiner(delimiter);
for (String element : elements) {
if (StringUtils.isEmpty(element)) {
continue;
}
stringJoiner.add(element);
}
return stringJoiner.length() == 0 ? Optional.empty() : Optional.of(stringJoiner.toString());
}
/**
* 将字符串按 {@link java.nio.charset.StandardCharsets#UTF_8} 进行编码
*
* @param str 待编码的字符串
* @return 编码后的字符串
*/
public static String urlEncoding(String str) {
return urlEncoding(str, StandardCharsets.UTF_8);
}
/**
* 将字符串按指定字符集进行编码
*
* @param str 待编码的字符串
* @param charset 字符集
* @return 编码后的字符串
* @throws UnsupportedException 如果提供了不支持的charset则会抛出该异常
*/
public static String urlEncoding(String str, Charset charset) {
try {
return URLEncoder.encode(str, charset.name());
} catch (UnsupportedEncodingException e) {
throw new UnsupportedException("不支持的字符集", e);
}
}
}