随机数小工具类
package com.*.*.utils;
import java.util.Random;
import org.apache.commons.lang3.StringUtils;
public class RandomUtils {
public static final String NUMBERS_AND_LETTERS = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
public static final String NUMBERS = "0123456789";
public static final String LETTERS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
public static final String CAPITAL_LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
public static final String LOWER_CASE_LETTERS = "abcdefghijklmnopqrstuvwxyz";
public static final String CAPITAL_HEX_NUMBERS = "0123456789ABCDEF";
public static final String LOWER_HEX_NUMBERS = "0123456789abcdef";
public static final String UPPER_CASE = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
public static final String SPECIAL_CHARACTER = "~!@#$%^&*<>/";
private RandomUtils() {
throw new AssertionError();
}
/**
* get a fixed-length random string, its a mixture of uppercase, lowercase
* letters and numbers
*
* @param length
* length
* @return RandomUtils
*/
public static String getRandomNumbersAndLetters(int length) {
return getRandom(NUMBERS_AND_LETTERS, length);
}
/**
* get a fixed-length random string, its a mixture of numbers
*
* @param length
* length
* @return RandomUtils
*/
public static String getRandomNumbers(int length) {
return getRandom(NUMBERS, length);
}
/**
* get a fixed-length random string, its a mixture of uppercase and
* lowercase letters
*
* @param length
* length
* @return RandomUtils
*/
public static String getRandomLetters(int length) {
return getRandom(LETTERS, length);
}
/**
* get a fixed-length random string, its a mixture of uppercase letters
*
* @param length
* length
* @return CapitalLetters
*/
public static String getRandomCapitalLetters(int length) {
return getRandom(CAPITAL_LETTERS, length);
}
/**
* get a fixed-length random string, its a mixture of lowercase letters
*
* @param length
* length
* @return get a fixed-length random string, its a mixture of lowercase
* letters
*/
public static String getRandomLowerCaseLetters(int length) {
return getRandom(LOWER_CASE_LETTERS, length);
}
/**
* 获取随机小写十六进制数
*
* @param length
* @return
*/
public static String getRandomLowerHexNumbers(int length) {
return getRandom(LOWER_HEX_NUMBERS, length);
}
/**
* 获取随机大写十六进制数
*
* @param length
* @return
*/
public static String getRandomCapitalHexNumbers(int length) {
return getRandom(CAPITAL_HEX_NUMBERS, length);
}
/**
* get a fixed-length random string, its a mixture of chars in source
*
* @param source
* source
* @param length
* length
* @return get a fixed-length random string, its a mixture of chars in
* source
*/
public static String getRandom(String source, int length) {
return StringUtils.isEmpty(source) ? null : getRandom(
source.toCharArray(), length);
}
/**
* get a fixed-length random string, its a mixture of chars in sourceChar
*
* @param sourceChar
* sourceChar
* @param length
* length
* @return get a fixed-length random string, its a mixture of chars in
* sourceChar
*/
public static String getRandom(char[] sourceChar, int length) {
if (sourceChar == null || sourceChar.length == 0 || length < 0) {
return null;
}
StringBuilder str = new StringBuilder(length);
Random random = new Random();
for (int i = 0; i < length; i++) {
str.append(sourceChar[random.nextInt(sourceChar.length)]);
}
return str.toString();
}
/**
*
* @param max
* 接受的数值
* @return 返回一个随机的数值
*/
public static int getRandom(int max) {
return getRandom(0, max);
}
/**
*
* @param min
* 最小
* @param max
* 最大
* @return 返回一个范围的数值
*/
public static int getRandom(int min, int max) {
if (min > max) {
return 0;
}
if (min == max) {
return min;
}
return min + new Random().nextInt(max - min);
}
/**
* Shuffling algorithm, Randomly permutes the specified array using a
* default source of randomness
*
* @param objArray
* 数组
* @return 从新的数组
*/
public static boolean shuffle(Object[] objArray) {
if (objArray == null) {
return false;
}
return shuffle(objArray, getRandom(objArray.length));
}
/**
* Shuffling algorithm, Randomly permutes the specified array
*
* @param objArray
* 数组
* @param shuffleCount
* 洗的个数
* @return 是否成功
*/
public static boolean shuffle(Object[] objArray, int shuffleCount) {
int length;
if (objArray == null || shuffleCount < 0
|| (length = objArray.length) < shuffleCount) {
return false;
}
for (int i = 1; i <= shuffleCount; i++) {
int random = getRandom(length - i);
Object temp = objArray[length - i];
objArray[length - i] = objArray[random];
objArray[random] = temp;
}
return true;
}
/**
* Shuffling algorithm, Randomly permutes the specified int array using a
* default source of randomness
*
* @param intArray
* 数组
* @return 洗牌之后
*/
public static int[] shuffle(int[] intArray) {
if (intArray == null) {
return null;
}
return shuffle(intArray, getRandom(intArray.length));
}
/**
* Shuffling algorithm, Randomly permutes the specified int array
*
* @param intArray
* 数组
* @param shuffleCount
* 范围
* @return 新的数组
*/
public static int[] shuffle(int[] intArray, int shuffleCount) {
int length;
if (intArray == null || shuffleCount < 0
|| (length = intArray.length) < shuffleCount) {
return null;
}
int[] out = new int[shuffleCount];
for (int i = 1; i <= shuffleCount; i++) {
int random = getRandom(length - i);
out[i - 1] = intArray[random];
int temp = intArray[length - i];
intArray[length - i] = intArray[random];
intArray[random] = temp;
}
return out;
}
public static String getRandPwd(){
StringBuffer pwd=new StringBuffer();
Random rand = new Random();
//随机取4个大写字母
for (int i = 0; i < 4; i++)
{
pwd.append(UPPER_CASE.charAt(rand.nextInt(26)) + "");
}
//随机取一个特殊字符
for(int j=0;j<1;j++){
pwd.append(SPECIAL_CHARACTER.charAt(rand.nextInt(12)));
}
//随机取三个数字
for(int k=0;k<3;k++){
pwd.append(NUMBERS.charAt(rand.nextInt(10)));
}
return pwd.toString();
}
}