com.alibaba.nacos.common.utils.StringUtils Maven / Gradle / Ivy
/*
* Copyright 1999-2018 Alibaba Group Holding Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.alibaba.nacos.common.utils;
import com.alibaba.nacos.api.common.Constants;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.nio.charset.Charset;
import java.util.Collection;
import java.util.Locale;
/**
* string util.
*
* @author Nacos
*/
public class StringUtils {
public static final String DOT = ".";
private static final int INDEX_NOT_FOUND = -1;
public static final String COMMA = ",";
public static final String EMPTY = "";
public static String newStringForUtf8(byte[] bytes) {
return new String(bytes, Charset.forName(Constants.ENCODE));
}
/**
* Judge whether string is blank.
*
* @param str string
* @return true if str is null, empty string or only blanks, otherwise false
*/
public static boolean isBlank(String str) {
int strLen;
if (str == null || (strLen = str.length()) == 0) {
return true;
}
for (int i = 0; i < strLen; i++) {
if (!Character.isWhitespace(str.charAt(i))) {
return false;
}
}
return true;
}
/**
* Judge whether all strings are blank.
*
* @param strs strings
* @return true if all strings are blank, otherwise false
*/
public static boolean isAllBlank(String... strs) {
for (String str : strs) {
if (isNotBlank(str)) {
return false;
}
}
return true;
}
public static boolean isNotBlank(String str) {
return !isBlank(str);
}
public static boolean isNotEmpty(String str) {
return !StringUtils.isEmpty(str);
}
public static boolean isEmpty(String str) {
return str == null || str.length() == 0;
}
public static String defaultIfEmpty(String str, String defaultStr) {
return StringUtils.isEmpty(str) ? defaultStr : str;
}
public static boolean equals(String str1, String str2) {
return str1 == null ? str2 == null : str1.equals(str2);
}
public static String trim(final String str) {
return str == null ? null : str.trim();
}
/**
* Substring between two index.
*
* @param str string
* @param open start index to sub
* @param close end index to sub
* @return substring
*/
public static String substringBetween(String str, String open, String close) {
if (str == null || open == null || close == null) {
return null;
}
int start = str.indexOf(open);
if (start != INDEX_NOT_FOUND) {
int end = str.indexOf(close, start + open.length());
if (end != INDEX_NOT_FOUND) {
return str.substring(start + open.length(), end);
}
}
return null;
}
/**
* Join object with input separator.
*
* @param collection collection of objects need to join
* @param separator separator
* @return joined string
*/
public static String join(Collection collection, String separator) {
if (collection == null) {
return null;
}
StringBuilder stringBuilder = new StringBuilder();
Object[] objects = collection.toArray();
for (int i = 0; i < collection.size() - 1; i++) {
stringBuilder.append(objects[i].toString()).append(separator);
}
if (collection.size() > 0) {
stringBuilder.append(objects[collection.size() - 1]);
}
return stringBuilder.toString();
}
public static String escapeJavaScript(String str) {
return escapeJavaStyleString(str, true, true);
}
private static String escapeJavaStyleString(String str, boolean escapeSingleQuotes, boolean escapeForwardSlash) {
if (str == null) {
return null;
}
try {
StringWriter writer = new StringWriter(str.length() * 2);
escapeJavaStyleString(writer, str, escapeSingleQuotes, escapeForwardSlash);
return writer.toString();
} catch (IOException ioe) {
// this should never ever happen while writing to a StringWriter
return null;
}
}
private static void escapeJavaStyleString(Writer out, String str, boolean escapeSingleQuote,
boolean escapeForwardSlash) throws IOException {
if (out == null) {
throw new IllegalArgumentException("The Writer must not be null");
}
if (str == null) {
return;
}
int sz;
sz = str.length();
for (int i = 0; i < sz; i++) {
char ch = str.charAt(i);
// handle unicode
if (ch > 0xfff) {
out.write("\\u" + hex(ch));
} else if (ch > 0xff) {
out.write("\\u0" + hex(ch));
} else if (ch > 0x7f) {
out.write("\\u00" + hex(ch));
} else if (ch < 32) {
switch (ch) {
case '\b':
out.write('\\');
out.write('b');
break;
case '\n':
out.write('\\');
out.write('n');
break;
case '\t':
out.write('\\');
out.write('t');
break;
case '\f':
out.write('\\');
out.write('f');
break;
case '\r':
out.write('\\');
out.write('r');
break;
default:
if (ch > 0xf) {
out.write("\\u00" + hex(ch));
} else {
out.write("\\u000" + hex(ch));
}
break;
}
} else {
switch (ch) {
case '\'':
if (escapeSingleQuote) {
out.write('\\');
}
out.write('\'');
break;
case '"':
out.write('\\');
out.write('"');
break;
case '\\':
out.write('\\');
out.write('\\');
break;
case '/':
if (escapeForwardSlash) {
out.write('\\');
}
out.write('/');
break;
default:
out.write(ch);
break;
}
}
}
}
private static String hex(char ch) {
return Integer.toHexString(ch).toUpperCase(Locale.ENGLISH);
}
// The following utility functions are extracted from org.apache.commons.lang3
// start
/**
* Checks if CharSequence contains a search CharSequence irrespective of case, handling {@code null}.
* Case-insensitivity is defined as by {@link String#equalsIgnoreCase(String)}.
*
* A {@code null} CharSequence will return {@code false}.
*
*
* StringUtils.contains(null, *) = false
* StringUtils.contains(*, null) = false
* StringUtils.contains("", "") = true
* StringUtils.contains("abc", "") = true
* StringUtils.contains("abc", "a") = true
* StringUtils.contains("abc", "z") = false
* StringUtils.contains("abc", "A") = true
* StringUtils.contains("abc", "Z") = false
*
*
* @param str the CharSequence to check, may be null
* @param searchStr the CharSequence to find, may be null
* @return true if the CharSequence contains the search CharSequence irrespective of case or false if not or {@code
* null} string input
* @since 3.0 Changed signature from containsIgnoreCase(String, String) to containsIgnoreCase(CharSequence,
* CharSequence)
*/
public static boolean containsIgnoreCase(final CharSequence str, final CharSequence searchStr) {
if (str == null || searchStr == null) {
return false;
}
final int len = searchStr.length();
final int max = str.length() - len;
for (int i = 0; i <= max; i++) {
if (regionMatches(str, true, i, searchStr, 0, len)) {
return true;
}
}
return false;
}
/**
* Green implementation of regionMatches.
*
* @param cs the {@code CharSequence} to be processed
* @param ignoreCase whether or not to be case insensitive
* @param thisStart the index to start on the {@code cs} CharSequence
* @param substring the {@code CharSequence} to be looked for
* @param start the index to start on the {@code substring} CharSequence
* @param length character length of the region
* @return whether the region matched
*/
static boolean regionMatches(final CharSequence cs, final boolean ignoreCase, final int thisStart,
final CharSequence substring, final int start, final int length) {
if (cs instanceof String && substring instanceof String) {
return ((String) cs).regionMatches(ignoreCase, thisStart, (String) substring, start, length);
}
int index1 = thisStart;
int index2 = start;
int tmpLen = length;
while (tmpLen-- > 0) {
final char c1 = cs.charAt(index1++);
final char c2 = substring.charAt(index2++);
if (c1 == c2) {
continue;
}
if (!ignoreCase) {
return false;
}
// The same check as in String.regionMatches():
if (Character.toUpperCase(c1) != Character.toUpperCase(c2) && Character.toLowerCase(c1) != Character
.toLowerCase(c2)) {
return false;
}
}
return true;
}
/**
* Compares two CharSequences, returning {@code true} if they represent
* equal sequences of characters, ignoring case.
*
* {@code null}s are handled without exceptions. Two {@code null}
* references are considered equal. Comparison is case insensitive.
*
*
* StringUtils.equalsIgnoreCase(null, null) = true
* StringUtils.equalsIgnoreCase(null, "abc") = false
* StringUtils.equalsIgnoreCase("abc", null) = false
* StringUtils.equalsIgnoreCase("abc", "abc") = true
* StringUtils.equalsIgnoreCase("abc", "ABC") = true
*
*
* @param str1 the first CharSequence, may be null
* @param str2 the second CharSequence, may be null
* @return {@code true} if the CharSequence are equal, case insensitive, or both {@code null}
* @since 3.0 Changed signature from equalsIgnoreCase(String, String) to equalsIgnoreCase(CharSequence,
* CharSequence)
*/
public static boolean equalsIgnoreCase(final CharSequence str1, final CharSequence str2) {
if (str1 == null || str2 == null) {
return str1 == str2;
} else if (str1 == str2) {
return true;
} else if (str1.length() != str2.length()) {
return false;
} else {
return CharSequenceUtils.regionMatches(str1, true, 0, str2, 0, str1.length());
}
}
static class CharSequenceUtils {
/**
* Green implementation of regionMatches.
*
* @param cs the {@code CharSequence} to be processed
* @param ignoreCase whether or not to be case insensitive
* @param thisStart the index to start on the {@code cs} CharSequence
* @param substring the {@code CharSequence} to be looked for
* @param start the index to start on the {@code substring} CharSequence
* @param length character length of the region
* @return whether the region matched
*/
static boolean regionMatches(final CharSequence cs, final boolean ignoreCase, final int thisStart,
final CharSequence substring, final int start, final int length) {
if (cs instanceof String && substring instanceof String) {
return ((String) cs).regionMatches(ignoreCase, thisStart, (String) substring, start, length);
}
int index1 = thisStart;
int index2 = start;
int tmpLen = length;
while (tmpLen-- > 0) {
final char c1 = cs.charAt(index1++);
final char c2 = substring.charAt(index2++);
if (c1 == c2) {
continue;
}
if (!ignoreCase) {
return false;
}
// The same check as in String.regionMatches():
if (Character.toUpperCase(c1) != Character.toUpperCase(c2) && Character.toLowerCase(c1) != Character
.toLowerCase(c2)) {
return false;
}
}
return true;
}
}
// end
}
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