原文:Java随机取字符串的工具类
源代码下载地址:http://www.zuidaima.com/share/1550463479532544.htm
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Java 随机取字符串的工具类 可以全部是数字,字符,也可以字符和数字组合的工具类,希望能给大家带来帮助
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package com.zuidaima.test; import java.util.Random; public class RandomUtils { public static final String ALLCHAR = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"; public static final String LETTERCHAR = "abcdefghijkllmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"; public static final String NUMBERCHAR = "0123456789"; /** * 返回一个定长的随机字符串(只包含大小写字母、数字) * @param length 随机字符串长度 * @author www.zuidaima.com * @return 随机字符串 */ public static String generateString(int length) { StringBuffer sb = new StringBuffer(); Random random = new Random(); for (int i = 0; i < length; i++) { sb.append(ALLCHAR.charAt(random.nextInt(ALLCHAR.length()))); } return sb.toString(); } /** * 返回一个定长的随机纯字母字符串(只包含大小写字母) * @param length 随机字符串长度 * @author www.zuidaima.com * @return 随机字符串 */ public static String generateMixString(int length) { StringBuffer sb = new StringBuffer(); Random random = new Random(); for (int i = 0; i < length; i++) { sb.append(ALLCHAR.charAt(random.nextInt(LETTERCHAR.length()))); } return sb.toString(); } /** * 返回一个定长的随机纯大写字母字符串(只包含大小写字母) * * @param length 随机字符串长度 * @return 随机字符串 */ public static String generateLowerString(int length) { return generateMixString(length).toLowerCase(); } /** * 返回一个定长的随机纯小写字母字符串(只包含大小写字母) * * @param length 随机字符串长度 * @author www.zuidaima.com * @return 随机字符串 */ public static String generateUpperString(int length) { return generateMixString(length).toUpperCase(); } /** * 生成一个定长的纯0字符串 * * @param length 字符串长度 * @return 纯0字符串 */ public static String generateZeroString(int length) { StringBuffer sb = new StringBuffer(); for (int i = 0; i < length; i++) { sb.append('0'); } return sb.toString(); } /** * 根据数字生成一个定长的字符串,长度不够前面补0 * * @param num 数字 * @param fixdlenth 字符串长度 * @author www.zuidaima.com * @return 定长的字符串 */ public static String toFixdLengthString(long num, int fixdlenth) { StringBuffer sb = new StringBuffer(); String strNum = String.valueOf(num); if (fixdlenth - strNum.length() >= 0) { sb.append(generateZeroString(fixdlenth - strNum.length())); } else { throw new RuntimeException("将数字" + num + "转化为长度为" + fixdlenth + "的字符串发生异常!"); } sb.append(strNum); return sb.toString(); } /** * 根据数字生成一个定长的字符串,长度不够前面补0 * * @param num 数字 * @param fixdlenth 字符串长度 * @author www.zuidaima.com * @return 定长的字符串 */ public static String toFixdLengthString(int num, int fixdlenth) { StringBuffer sb = new StringBuffer(); String strNum = String.valueOf(num); if (fixdlenth - strNum.length() >= 0) { sb.append(generateZeroString(fixdlenth - strNum.length())); } else { throw new RuntimeException("将数字" + num + "转化为长度为" + fixdlenth + "的字符串发生异常!"); } sb.append(strNum); return sb.toString(); } /** * 每次生成的len位数都不相同 * @param param * @return 定长的数字 */ public static int getNotSimple(int[] param,int len) { Random rand = new Random(); for (int i = param.length; i > 1; i--) { int index = rand.nextInt(i); int tmp = param[index]; param[index] = param[i - 1]; param[i - 1] = tmp; } int result = 0; for(int i = 0; i < len; i++) { result = result * 10 + param[i]; } return result; } public static void main(String[] args) { System.out.println(generateString(10)); System.out.println(generateMixString(10)); System.out.println(generateLowerString(10)); System.out.println(generateUpperString(10)); System.out.println(generateZeroString(10)); System.out.println(toFixdLengthString(123, 10)); System.out.println(toFixdLengthString(123L, 10)); int[] in = {1,2,3,4,5,6,7}; System.out.println(getNotSimple(in,3)); } }
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