JavaCodeAcc/src/util/StringUtil.java at master · kylez7/JavaCodeAcc · GitHub

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package util;

import java.util.Random;

/**

* Util for String

* @author liu yuning

public class StringUtil {

private static final int DEFAULT_STRING_LENGTH = 10;

private static final String LETTERS = "abcdefghijkllmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

private static Random random = new Random();

/**

* Don't let anyone instantiate this class.

private StringUtil() {

}

/**

* @param str

* @return {@code true} if the input {@code String} is null or ""

public static boolean empty(final String str) {

return str == null || str.trim().isEmpty();

}

/**

* generate random string

* @return a random string

public static String generateRandomString() {

return generateRandomString(DEFAULT_STRING_LENGTH);

}

/**

* generate random string using all letters and the given length

* @param stringLength

* @return a random string

public static String generateRandomString(int stringLength) {

if (stringLength <= 0) {

stringLength = DEFAULT_STRING_LENGTH;

}

StringBuilder stringBuilder = new StringBuilder();

for (int i = 0; i < stringLength; i++) {

stringBuilder

.append(LETTERS.charAt(random.nextInt(LETTERS.length())));

}

return stringBuilder.toString();

}

/**

* repeat a {@code String} called repeatStr for repeatNum times

* @param repeatStr

* @param repeatNum

* @return {@code String} repeatedString

public static String repeatableString(String repeatStr, int repeatNum) {

StringBuilder stringBuilder = new StringBuilder();

while (repeatNum-- > 0) {

stringBuilder.append(repeatStr);

}

return stringBuilder.toString();

}

JavaCodeAcc/src/util/StringUtil.java at master · kylez7/JavaCodeAcc · GitHub

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