Spring Utils工具类常用方法实例

Spring Utils工具类常用方法实例

Spring提供的工具类，主要用于框架内部使用，这个类提供了一些简单的方法，并且提供了易于使用的方法在分割字符串，如CSV字符串，以及集合和数组。

StringUtils提供常用的方法如下：

判断对象对象是否为null或者空字符串

public static boolean isEmpty(@Nullable Object str) {

return (str == null || "".equals(str));

}

判断给的序列是否为空或者length为0

public static boolean hasLength(@Nullable CharSequence str) {

return (str != null && str.length() > 0);

}

public static boolean hasLength(@Nullable String str) {

return (str != null && !str.isEmpty());

}

判断字符串是否以某个字符串开头

public static boolean startsWithIgnoreCase(@Nullable String str, @Nullable String prefix) {

return (str != null && prefix != null && str.length() >= prefix.length() &&

str.regionMatches(true, 0, prefix, 0, prefix.length()));

}

判断字符串是否以某个字符串结尾

public static boolean endsWithIgnoreCase(@Nullable String str, @Nullable String suffix) {

return (str != null && suffix != null && str.length() >= suffix.length() &&

str.regionMatches(true, str.length() - suffix.length(), suffix, 0, suffix.length()));

}

用另一个字符串替换字符串中出现的所有子字符串

public static String replace(String inString, String oldPattern, @Nullable String newPattern) {

if (!hasLength(inString) || !hasLength(oldPattern) || newPattern == null) {

return inString;

}

//oldPattern字符串第一次出现的位置

int index = inString.indexOf(oldPattern);

if (index == -1) {

// no occurrence -> can return input as-is

return inString;

}

//字符串长度

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();

}

根据给定的路径规范化路径

public static String cRCEKYmIleanPath(String path) {

if (!hasLength(path)) {

return path;

}

//用新字符串替换旧字符串

String pathToUse = replace(path, WINDOWS_FOLDER_SEPARATOR, FOLDER_SEPARATOR);

// Shortcut if there is no work to do

if (pathToUse.indexOf('.') == -1) {

return pathToUse;

}

// Strip prefix from path to analyze, to not treat it as part of the

// first path element. This is necessary to corrRCEKYmIectly 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);

LinkedList 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);

}

// If nothing else left, at least explicitly point to current path.

if (pathElements.size() == 1 && "".equals(pathElements.getLast()) && !prefix.endsWith(FOLDER_SEPARATOR)) {

pathElements.add(0, CURRENT_PATH);

}

return prefix + collectionToDelimitedString(pathElements, FOLDER_SEPARATOR);

}

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