com.alibaba.antx.util.StringUtil Maven / Gradle / Ivy
The newest version!
/*
* Copyright (c) 2002-2012 Alibaba Group Holding Limited.
* All rights reserved.
*
* 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.antx.util;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
/**
* 和字符串有关的小工具.
*
* @author Michael Zhou
*/
public class StringUtil {
/**
* 检查字符串是否为null或空字符串.
*
* @param str 要检查的字符串
* @return 如果为空, 则返回true
*/
public static boolean isEmpty(String str) {
return str == null || str.length() == 0;
}
public static boolean isEmpty(Object str) {
return isEmpty(toString(str));
}
/**
* 检查字符串是否为null或空字符串.
*
* @param str 要检查的字符串
* @return 如果为空, 则返回true
*/
public static boolean isBlank(String str) {
return str == null || str.trim().length() == 0;
}
public static boolean isBlank(Object str) {
return isBlank(toString(str));
}
/**
* 取得类名，不包括package名。
*
* @param clazz 要查看的类
* @return 短类名
*/
public static String getShortClassName(Class clazz) {
return getShortClassName(clazz.getName());
}
/**
* 取得类名，不包括package名。
*
* @param className 要查看的类名
* @return 短类名
*/
public static String getShortClassName(String className) {
int index = className.lastIndexOf('.');
return className.substring(index + 1);
}
/**
* 将字符串按空格和逗号分解.
*
* @param str 要分解的字符串
* @return 字符串数组
*/
public static String[] split(String str) {
return split(str, ",");
}
public static String join(Object[] array) {
return join(array, ",");
}
/**
* 将数组中的元素连接成一个字符串。
*
*
* StringUtil.join(null, *) = null
* StringUtil.join([], *) = ""StringUtil.join([null], *) = ""
* StringUtil.join(["a", "b", "c"], "--") = "a--b--c"
* StringUtil.join(["a", "b", "c"], null) = "abc"
* StringUtil.join(["a", "b", "c"], "") = "abc"
* StringUtil.join([null, "", "a"], ',') = ",,a"
*
*
* @param array 要连接的数组
* @param separator 分隔符
* @return 连接后的字符串，如果原数组为null，则返回null
*/
public static String join(Object[] array, String separator) {
if (array == null) {
return null;
}
if (separator == null) {
separator = "";
}
int arraySize = array.length;
// ArraySize == 0: Len = 0
// ArraySize > 0: Len = NofStrings *(len(firstString) + len(separator))
// (估计大约所有的字符串都一样长)
int bufSize = arraySize == 0 ? 0
: arraySize
* ((array[0] == null ? 16 : array[0].toString().length()) + (separator != null ? separator
.length() : 0));
StringBuffer buf = new StringBuffer(bufSize);
for (int i = 0; i < arraySize; i++) {
if (separator != null && i > 0) {
buf.append(separator);
}
if (array[i] != null) {
buf.append(array[i]);
}
}
return buf.toString();
}
/**
* 将字符串按空格和逗号分解.
*
* @param str 要分解的字符串
* @return 字符串数组
*/
public static String[] splitPath(String str) {
return split(str, "," + File.pathSeparator);
}
/**
* 将字符串按指定分隔符分解.
*
* @param str 要分解的字符串
* @param delimiters 分隔符
* @return 字符串数组
*/
public static String[] split(String str, String delimiters) {
if (str == null || str.trim().length() == 0) {
return new String[0];
}
List tokens = new ArrayList();
StringTokenizer tokenizer = new StringTokenizer(str, delimiters);
while (tokenizer.hasMoreTokens()) {
String token = tokenizer.nextToken().trim();
if (token.length() > 0) {
tokens.add(token);
}
}
return (String[]) tokens.toArray(new String[tokens.size()]);
}
/**
* 删除两端空白。
*
* @param str 要处理的字符串
* @return 除去两端空白的字符串，如果字符串为null，则返回空字符串
*/
public static String trimWhitespace(String str) {
if (str == null) {
return "";
}
return str.trim();
}
/**
* 删除所有空白。
*
* @param str 要处理的字符串
* @return 除去空白的字符串，如果字符串为null，则返回空字符串
*/
public static String deleteWhitespace(String str) {
if (str == null) {
return "";
}
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < str.length(); i++) {
char ch = str.charAt(i);
if (!Character.isWhitespace(ch)) {
buffer.append(ch);
}
}
return buffer.toString();
}
/**
* 通过将不合法的字符替换成"_", 将不合法的Java Identifier字符转换成合法的ID.
*
* @param id 要转换的字符串
* @return 合法的ID
*/
public static String getValidIdentifier(String id) {
return getValidIdentifier(id, null);
}
/**
* 通过替换不合法的字符, 将不合法的Java Identifier字符转换成合法的ID.
*
* @param id 要转换的字符串
* @param replaceInvalid 用来替换不合法字符的字符串, 如果不指定, 则使用默认字符串"_"
* @return 合法的ID
*/
public static String getValidIdentifier(String id, String replaceInvalid) {
if (replaceInvalid == null) {
replaceInvalid = "_";
}
if (id == null || id.length() == 0) {
return replaceInvalid;
}
boolean replaced = false;
StringBuffer buffer = new StringBuffer(id.length());
char c = id.charAt(0);
if (Character.isJavaIdentifierStart(c)) {
buffer.append(c);
} else {
buffer.append(replaceInvalid);
replaced = true;
}
for (int i = 1; i < id.length(); i++) {
c = id.charAt(i);
if (Character.isJavaIdentifierPart(c)) {
buffer.append(c);
replaced = false;
} else {
if (!replaced) {
replaced = true;
buffer.append(replaceInvalid);
}
}
}
return buffer.toString();
}
/**
* 扩展并左对齐字符串，用空格' '填充右边。
*
*
* StringUtil.alignLeft(null, *) = null
* StringUtil.alignLeft("", 3) = " "StringUtil.alignLeft("bat", 3) = "bat"
* StringUtil.alignLeft("bat", 5) = "bat "StringUtil.alignLeft("bat", 1) = "bat"
* StringUtil.alignLeft("bat", -1) = "bat"
*
*
* @param str 要对齐的字符串
* @param size 扩展字符串到指定宽度
* @return 扩展后的字符串，如果字符串为null，则返回null
*/
public static String alignLeft(String str, int size) {
return alignLeft(str, size, ' ');
}
/**
* 扩展并左对齐字符串，用指定字符填充右边。
*
*
* StringUtil.alignLeft(null, *, *) = null
* StringUtil.alignLeft("", 3, 'z') = "zzz"StringUtil.alignLeft("bat", 3, 'z') = "bat"
* StringUtil.alignLeft("bat", 5, 'z') = "batzz"StringUtil.alignLeft("bat", 1, 'z') = "bat"
* StringUtil.alignLeft("bat", -1, 'z') = "bat"
*
*
* @param str 要对齐的字符串
* @param size 扩展字符串到指定宽度
* @param padChar 填充字符
* @return 扩展后的字符串，如果字符串为null，则返回null
*/
public static String alignLeft(String str, int size, char padChar) {
if (str == null) {
return null;
}
int pads = size - str.length();
if (pads <= 0) {
return str;
}
return alignLeft(str, size, String.valueOf(padChar));
}
/**
* 扩展并左对齐字符串，用指定字符串填充右边。
*
*
* StringUtil.alignLeft(null, *, *) = null
* StringUtil.alignLeft("", 3, "z") = "zzz"StringUtil.alignLeft("bat", 3, "yz") = "bat"
* StringUtil.alignLeft("bat", 5, "yz") = "batyz"
* StringUtil.alignLeft("bat", 8, "yz") = "batyzyzy"
* StringUtil.alignLeft("bat", 1, "yz") = "bat"StringUtil.alignLeft("bat", -1, "yz") = "bat"
* StringUtil.alignLeft("bat", 5, null) = "bat "
* StringUtil.alignLeft("bat", 5, "") = "bat "
*
*
* @param str 要对齐的字符串
* @param size 扩展字符串到指定宽度
* @param padStr 填充字符串
* @return 扩展后的字符串，如果字符串为null，则返回null
*/
public static String alignLeft(String str, int size, String padStr) {
if (str == null) {
return null;
}
if (padStr == null || padStr.length() == 0) {
padStr = " ";
}
int padLen = padStr.length();
int strLen = str.length();
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 {
char[] padding = new char[pads];
char[] padChars = padStr.toCharArray();
for (int i = 0; i < pads; i++) {
padding[i] = padChars[i % padLen];
}
return str.concat(new String(padding));
}
}
/**
* 扩展并右对齐字符串，用空格' '填充左边。
*
*
* StringUtil.alignRight(null, *) = null
* StringUtil.alignRight("", 3) = " "StringUtil.alignRight("bat", 3) = "bat"
* StringUtil.alignRight("bat", 5) = " bat"StringUtil.alignRight("bat", 1) = "bat"
* StringUtil.alignRight("bat", -1) = "bat"
*
*
* @param str 要对齐的字符串
* @param size 扩展字符串到指定宽度
* @return 扩展后的字符串，如果字符串为null，则返回null
*/
public static String alignRight(String str, int size) {
return alignRight(str, size, ' ');
}
/**
* 扩展并右对齐字符串，用指定字符填充左边。
*
*
* StringUtil.alignRight(null, *, *) = null
* StringUtil.alignRight("", 3, 'z') = "zzz"StringUtil.alignRight("bat", 3, 'z') = "bat"
* StringUtil.alignRight("bat", 5, 'z') = "zzbat"StringUtil.alignRight("bat", 1, 'z') = "bat"
* StringUtil.alignRight("bat", -1, 'z') = "bat"
*
*
* @param str 要对齐的字符串
* @param size 扩展字符串到指定宽度
* @param padChar 填充字符
* @return 扩展后的字符串，如果字符串为null，则返回null
*/
public static String alignRight(String str, int size, char padChar) {
if (str == null) {
return null;
}
int pads = size - str.length();
if (pads <= 0) {
return str;
}
return alignRight(str, size, String.valueOf(padChar));
}
/**
* 扩展并右对齐字符串，用指定字符串填充左边。
*
*
* StringUtil.alignRight(null, *, *) = null
* StringUtil.alignRight("", 3, "z") = "zzz"StringUtil.alignRight("bat", 3, "yz") = "bat"
* StringUtil.alignRight("bat", 5, "yz") = "yzbat"
* StringUtil.alignRight("bat", 8, "yz") = "yzyzybat"
* StringUtil.alignRight("bat", 1, "yz") = "bat"StringUtil.alignRight("bat", -1, "yz") = "bat"
* StringUtil.alignRight("bat", 5, null) = " bat"
* StringUtil.alignRight("bat", 5, "") = " bat"
*
*
* @param str 要对齐的字符串
* @param size 扩展字符串到指定宽度
* @param padStr 填充字符串
* @return 扩展后的字符串，如果字符串为null，则返回null
*/
public static String alignRight(String str, int size, String padStr) {
if (str == null) {
return null;
}
if (padStr == null || padStr.length() == 0) {
padStr = " ";
}
int padLen = padStr.length();
int strLen = str.length();
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 {
char[] padding = new char[pads];
char[] padChars = padStr.toCharArray();
for (int i = 0; i < pads; i++) {
padding[i] = padChars[i % padLen];
}
return new String(padding).concat(str);
}
}
/**
* 扩展并居中字符串，用空格' '填充两边。
*
*
* StringUtil.center(null, *) = null
* StringUtil.center("", 4) = " "StringUtil.center("ab", -1) = "ab"
* StringUtil.center("ab", 4) = " ab "StringUtil.center("abcd", 2) = "abcd"
* StringUtil.center("a", 4) = " a "
*
*
* @param str 要对齐的字符串
* @param size 扩展字符串到指定宽度
* @return 扩展后的字符串，如果字符串为null，则返回null
*/
public static String center(String str, int size) {
return center(str, size, ' ');
}
/**
* 扩展并居中字符串，用指定字符填充两边。
*
*
* StringUtil.center(null, *, *) = null
* StringUtil.center("", 4, ' ') = " "StringUtil.center("ab", -1, ' ') = "ab"
* StringUtil.center("ab", 4, ' ') = " ab "StringUtil.center("abcd", 2, ' ') = "abcd"
* StringUtil.center("a", 4, ' ') = " a "StringUtil.center("a", 4, 'y') = "yayy"
*
*
* @param str 要对齐的字符串
* @param size 扩展字符串到指定宽度
* @param padChar 填充字符
* @return 扩展后的字符串，如果字符串为null，则返回null
*/
public static String center(String str, int size, char padChar) {
if (str == null || size <= 0) {
return str;
}
int strLen = str.length();
int pads = size - strLen;
if (pads <= 0) {
return str;
}
str = alignRight(str, strLen + pads / 2, padChar);
str = alignLeft(str, size, padChar);
return str;
}
/**
* 扩展并居中字符串，用指定字符串填充两边。
*
*
* StringUtil.center(null, *, *) = null
* StringUtil.center("", 4, " ") = " "StringUtil.center("ab", -1, " ") = "ab"
* StringUtil.center("ab", 4, " ") = " ab "StringUtil.center("abcd", 2, " ") = "abcd"
* StringUtil.center("a", 4, " ") = " a "StringUtil.center("a", 4, "yz") = "yayz"
* StringUtil.center("abc", 7, null) = " abc "StringUtil.center("abc", 7, "") = " abc "
*
*
* @param str 要对齐的字符串
* @param size 扩展字符串到指定宽度
* @param padStr 填充字符串
* @return 扩展后的字符串，如果字符串为null，则返回null
*/
public static String center(String str, int size, String padStr) {
if (str == null || size <= 0) {
return str;
}
if (padStr == null || padStr.length() == 0) {
padStr = " ";
}
int strLen = str.length();
int pads = size - strLen;
if (pads <= 0) {
return str;
}
str = alignRight(str, strLen + pads / 2, padStr);
str = alignLeft(str, size, padStr);
return str;
}
/**
* 去除数据中的空值。
*
* @param strs 字符串数组
* @return 整理后的数组
*/
public static String[] trimStringArray(String[] strs) {
if (strs == null) {
return new String[0];
}
List strList = new ArrayList(strs.length);
for (String str2 : strs) {
String str = StringUtil.trimWhitespace(str2);
if (str.length() > 0) {
strList.add(str);
}
}
return (String[]) strList.toArray(new String[strList.size()]);
}
public static String toString(Object obj) {
return obj == null ? "" : obj.toString();
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy