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/*
* Copyright 2002-2019 the original author or authors.
*
* 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
*
* https://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.feilong.lib.springframework.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
/**
* Miscellaneous {@link String} utility methods.
*
*
* Mainly for internal use within the framework; consider
* Apache's Commons Lang
* for a more comprehensive suite of {@code String} utilities.
*
*
* This class delivers some simple functionality that should really be
* provided by the core Java {@link String} and {@link StringBuilder}
* classes. It also provides easy-to-use methods to convert between
* delimited strings, such as CSV strings, and collections and arrays.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @author Keith Donald
* @author Rob Harrop
* @author Rick Evans
* @author Arjen Poutsma
* @author Sam Brannen
* @author Brian Clozel
* @since 16 April 2001
*/
public abstract class StringUtils{
private static final String FOLDER_SEPARATOR = "/";
private static final String WINDOWS_FOLDER_SEPARATOR = "\\";
private static final String TOP_PATH = "..";
private static final String CURRENT_PATH = ".";
//---------------------------------------------------------------------
// General convenience methods for working with Strings
//---------------------------------------------------------------------
/**
* Check that the given {@code String} is neither {@code null} nor of length 0.
*
* Note: this method returns {@code true} for a {@code String} that
* purely consists of whitespace.
*
* @param str
* the {@code String} to check (may be {@code null})
* @return {@code true} if the {@code String} is not {@code null} and has length
* @see #hasLength(CharSequence)
* @see #hasText(String)
*/
public static boolean hasLength(String str){
return (str != null && !str.isEmpty());
}
/**
* Check whether the given {@code String} contains actual text.
*
* More specifically, this method returns {@code true} if the
* {@code String} is not {@code null}, its length is greater than 0,
* and it contains at least one non-whitespace character.
*
* @param str
* the {@code String} to check (may be {@code null})
* @return {@code true} if the {@code String} is not {@code null}, its
* length is greater than 0, and it does not contain whitespace only
* @see #hasText(CharSequence)
*/
public static boolean hasText(String str){
return (hasLength(str) && containsText(str));
}
private static boolean containsText(CharSequence str){
int strLen = str.length();
for (int i = 0; i < strLen; i++){
if (!Character.isWhitespace(str.charAt(i))){
return true;
}
}
return false;
}
/**
* Replace all occurrences of a substring within a string with another string.
*
* @param inString
* {@code String} to examine
* @param oldPattern
* {@code String} to replace
* @param newPattern
* {@code String} to insert
* @return a {@code String} with the replacements
*/
public static String replace(String inString,String oldPattern,String newPattern){
if (!hasLength(inString) || !hasLength(oldPattern) || newPattern == null){
return inString;
}
int index = inString.indexOf(oldPattern);
if (index == -1){
// no occurrence -> can return input as-is
return inString;
}
int capacity = inString.length();
if (newPattern.length() > oldPattern.length()){
capacity += 16;
}
StringBuilder sb = new StringBuilder(capacity);
int pos = 0; // our position in the old string
int patLen = oldPattern.length();
while (index >= 0){
sb.append(inString, pos, index);
sb.append(newPattern);
pos = index + patLen;
index = inString.indexOf(oldPattern, pos);
}
// append any characters to the right of a match
sb.append(inString, pos, inString.length());
return sb.toString();
}
/**
* Delete any character in a given {@code String}.
*
* @param inString
* the original {@code String}
* @param charsToDelete
* a set of characters to delete.
* E.g. "az\n" will delete 'a's, 'z's and new lines.
* @return the resulting {@code String}
*/
public static String deleteAny(String inString,String charsToDelete){
if (!hasLength(inString) || !hasLength(charsToDelete)){
return inString;
}
StringBuilder sb = new StringBuilder(inString.length());
for (int i = 0; i < inString.length(); i++){
char c = inString.charAt(i);
if (charsToDelete.indexOf(c) == -1){
sb.append(c);
}
}
return sb.toString();
}
//---------------------------------------------------------------------
// Convenience methods for working with formatted Strings
//---------------------------------------------------------------------
/**
* Extract the filename from the given Java resource path,
* e.g. {@code "mypath/myfile.txt" -> "myfile.txt"}.
*
* @param path
* the file path (may be {@code null})
* @return the extracted filename, or {@code null} if none
*/
public static String getFilename(String path){
if (path == null){
return null;
}
int separatorIndex = path.lastIndexOf(FOLDER_SEPARATOR);
return (separatorIndex != -1 ? path.substring(separatorIndex + 1) : path);
}
/**
* Apply the given relative path to the given Java resource path,
* assuming standard Java folder separation (i.e. "/" separators).
*
* @param path
* the path to start from (usually a full file path)
* @param relativePath
* the relative path to apply
* (relative to the full file path above)
* @return the full file path that results from applying the relative path
*/
public static String applyRelativePath(String path,String relativePath){
int separatorIndex = path.lastIndexOf(FOLDER_SEPARATOR);
if (separatorIndex != -1){
String newPath = path.substring(0, separatorIndex);
if (!relativePath.startsWith(FOLDER_SEPARATOR)){
newPath += FOLDER_SEPARATOR;
}
return newPath + relativePath;
}
return relativePath;
}
/**
* Normalize the path by suppressing sequences like "path/.." and
* inner simple dots.
*
* The result is convenient for path comparison. For other uses,
* notice that Windows separators ("\") are replaced by simple slashes.
*
* @param path
* the original path
* @return the normalized path
*/
public static String cleanPath(String path){
if (path == null){
return null;
}
String pathToUse = replace(path, WINDOWS_FOLDER_SEPARATOR, FOLDER_SEPARATOR);
// Strip prefix from path to analyze, to not treat it as part of the
// first path element. This is necessary to correctly parse paths like
// "file:core/../core/io/Resource.class", where the ".." should just
// strip the first "core" directory while keeping the "file:" prefix.
int prefixIndex = pathToUse.indexOf(':');
String prefix = "";
if (prefixIndex != -1){
prefix = pathToUse.substring(0, prefixIndex + 1);
if (prefix.contains(FOLDER_SEPARATOR)){
prefix = "";
}else{
pathToUse = pathToUse.substring(prefixIndex + 1);
}
}
if (pathToUse.startsWith(FOLDER_SEPARATOR)){
prefix = prefix + FOLDER_SEPARATOR;
pathToUse = pathToUse.substring(1);
}
String[] pathArray = delimitedListToStringArray(pathToUse, FOLDER_SEPARATOR);
List pathElements = new LinkedList<>();
int tops = 0;
for (int i = pathArray.length - 1; i >= 0; i--){
String element = pathArray[i];
if (CURRENT_PATH.equals(element)){
// Points to current directory - drop it.
}else if (TOP_PATH.equals(element)){
// Registering top path found.
tops++;
}else{
if (tops > 0){
// Merging path element with element corresponding to top path.
tops--;
}else{
// Normal path element found.
pathElements.add(0, element);
}
}
}
// Remaining top paths need to be retained.
for (int i = 0; i < tops; i++){
pathElements.add(0, TOP_PATH);
}
return prefix + collectionToDelimitedString(pathElements, FOLDER_SEPARATOR);
}
//---------------------------------------------------------------------
// Convenience methods for working with String arrays
//---------------------------------------------------------------------
/**
* Copy the given {@link Collection} into a {@code String} array.
*
* The {@code Collection} must contain {@code String} elements only.
*
* @param collection
* the {@code Collection} to copy
* @return the resulting {@code String} array
*/
public static String[] toStringArray(Collection collection){
if (collection == null){
return null;
}
return collection.toArray(new String[collection.size()]);
}
/**
* Take a {@code String} that is a delimited list and convert it into a
* {@code String} array.
*
* A single {@code delimiter} may consist of more than one character,
* but it will still be considered as a single delimiter string, rather
* than as bunch of potential delimiter characters, in contrast to
* {@link #tokenizeToStringArray}.
*
* @param str
* the input {@code String}
* @param delimiter
* the delimiter between elements (this is a single delimiter,
* rather than a bunch individual delimiter characters)
* @return an array of the tokens in the list
* @see #tokenizeToStringArray
*/
public static String[] delimitedListToStringArray(String str,String delimiter){
return delimitedListToStringArray(str, delimiter, null);
}
/**
* Take a {@code String} that is a delimited list and convert it into
* a {@code String} array.
*
* A single {@code delimiter} may consist of more than one character,
* but it will still be considered as a single delimiter string, rather
* than as bunch of potential delimiter characters, in contrast to
* {@link #tokenizeToStringArray}.
*
* @param str
* the input {@code String}
* @param delimiter
* the delimiter between elements (this is a single delimiter,
* rather than a bunch individual delimiter characters)
* @param charsToDelete
* a set of characters to delete; useful for deleting unwanted
* line breaks: e.g. "\r\n\f" will delete all new lines and line feeds in a {@code String}
* @return an array of the tokens in the list
* @see #tokenizeToStringArray
*/
public static String[] delimitedListToStringArray(String str,String delimiter,String charsToDelete){
if (str == null){
return new String[0];
}
if (delimiter == null){
return new String[] { str };
}
List result = new ArrayList<>();
if ("".equals(delimiter)){
for (int i = 0; i < str.length(); i++){
result.add(deleteAny(str.substring(i, i + 1), charsToDelete));
}
}else{
int pos = 0;
int delPos;
while ((delPos = str.indexOf(delimiter, pos)) != -1){
result.add(deleteAny(str.substring(pos, delPos), charsToDelete));
pos = delPos + delimiter.length();
}
if (str.length() > 0 && pos <= str.length()){
// Add rest of String, but not in case of empty input.
result.add(deleteAny(str.substring(pos), charsToDelete));
}
}
return toStringArray(result);
}
/**
* Convert a {@link Collection} to a delimited {@code String} (e.g. CSV).
*
* Useful for {@code toString()} implementations.
*
* @param coll
* the {@code Collection} to convert
* @param delim
* the delimiter to use (typically a ",")
* @param prefix
* the {@code String} to start each element with
* @param suffix
* the {@code String} to end each element with
* @return the delimited {@code String}
*/
public static String collectionToDelimitedString(Collection coll,String delim,String prefix,String suffix){
if (ObjectUtils.isEmpty(coll)){
return "";
}
StringBuilder sb = new StringBuilder();
Iterator it = coll.iterator();
while (it.hasNext()){
sb.append(prefix).append(it.next()).append(suffix);
if (it.hasNext()){
sb.append(delim);
}
}
return sb.toString();
}
/**
* Convert a {@code Collection} into a delimited {@code String} (e.g. CSV).
*
* Useful for {@code toString()} implementations.
*
* @param coll
* the {@code Collection} to convert
* @param delim
* the delimiter to use (typically a ",")
* @return the delimited {@code String}
*/
public static String collectionToDelimitedString(Collection coll,String delim){
return collectionToDelimitedString(coll, delim, "", "");
}
}