学步园

package cn.junit.util;</p> <p>import java.util.Random;</p> <p>public class RandomUtil {<br /> private static final String allChar = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";<br /> private static final String letterChar = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";<br /> private static final String digitChar = "0123456789";</p> <p> /**<br /> * 返回一个定长的随机字符串 (只包含数字)<br /> * @param length<br /> * 随机字符串长度<br /> * @return 随机字符串<br /> */<br /> public static String generateDigitString(int length){<br /> StringBuilder sb = new StringBuilder();<br /> Random random = new Random();<br /> for(int i=0;i<length;i++){<br /> sb.append(digitChar.charAt(random.nextInt(digitChar.length())));<br /> }<br /> return sb.toString();<br /> }<br /> /**<br /> * 生成一个位于最小值与最大值之间的整数<br /> * @param min<br /> * 最小值<br /> * @param max<br /> * 最大值<br /> * @return<br /> * 数<br /> */<br /> public static int generateIntBetweenMinMax(int min,int max){<br /> Random random = new Random();<br /> if(min > max){<br /> int tmp = 0;<br /> tmp = min;<br /> min = max;<br /> max = tmp;<br /> }<br /> return random.nextInt(max - min) + min;<br /> }<br /> /**<br /> * 返回一个定长的随机字符串(只包含大小写字母、数字)<br /> *<br /> * @param length<br /> * 随机字符串长度<br /> * @return 随机字符串<br /> */<br /> public static String generateString(int length) {<br /> StringBuilder sb = new StringBuilder();<br /> Random random = new Random();<br /> for (int i = 0; i < length; i++) {<br /> sb.append(allChar.charAt(random.nextInt(allChar.length())));<br /> }<br /> return sb.toString();<br /> }</p> <p> /**<br /> * 生成一个位于两数值之间的随机长度字符串<br /> * @param minLen 最小长度值<br /> * @param maxLen 最大长度值<br /> * @return 字符串<br /> */<br /> public static String generateString(int minLen,int maxLen){<br /> Random random = new Random();<br /> if(minLen > maxLen){<br /> int tmp = 0;<br /> tmp = minLen;<br /> minLen = maxLen;<br /> maxLen = tmp;<br /> }<br /> return generateString(random.nextInt(maxLen - minLen) + minLen);<br /> }</p> <p> /**<br /> * 返回一个定长的随机纯字母字符串(只包含大小写字母)<br /> *<br /> * @param length<br /> * 随机字符串长度<br /> * @return 随机字符串<br /> */<br /> public static String generateMixString(int length) {<br /> StringBuilder sb = new StringBuilder();<br /> Random random = new Random();<br /> for (int i = 0; i < length; i++) {<br /> sb.append(allChar.charAt(random.nextInt(letterChar.length())));<br /> }<br /> return sb.toString();<br /> }</p> <p> /**<br /> * 返回一个定长的随机纯小写字母字符串(只包含小写字母)<br /> *<br /> * @param length<br /> * 随机字符串长度<br /> * @return 随机字符串<br /> */<br /> public static String generateLowerString(int length) {<br /> return generateMixString(length).toLowerCase();<br /> }</p> <p> /**<br /> * 返回一个定长的随机纯大写字母字符串(只包含大写字母)<br /> *<br /> * @param length<br /> * 随机字符串长度<br /> * @return 随机字符串<br /> */<br /> public static String generateUpperString(int length) {<br /> return generateMixString(length).toUpperCase();<br /> }</p> <p> /**<br /> * 生成一个定长的纯0字符串<br /> *<br /> * @param length<br /> * 字符串长度<br /> * @return 纯0字符串<br /> */<br /> public static String generateZeroString(int length) {<br /> StringBuilder sb = new StringBuilder();<br /> for (int i = 0; i < length; i++) {<br /> sb.append('0');<br /> }<br /> return sb.toString();<br /> }</p> <p> /**<br /> * 根据数字生成一个定长的字符串，长度不够前面补0<br /> *<br /> * @param num<br /> * 数字<br /> * @param fixdlenth<br /> * 字符串长度<br /> * @return 定长的字符串<br /> */<br /> public static String toFixdLengthString(long num, int fixdlenth) {<br /> StringBuilder sb = new StringBuilder();<br /> String strNum = String.valueOf(num);<br /> if (fixdlenth - strNum.length() >= 0) {<br /> sb.append(generateZeroString(fixdlenth - strNum.length()));<br /> } else {<br /> throw new RuntimeException("将数字" + num + "转化为长度为" + fixdlenth<br /> + "的字符串发生异常！");<br /> }<br /> sb.append(strNum);<br /> return sb.toString();<br /> }</p> <p> /**<br /> * 根据数字生成一个定长的字符串，长度不够前面补0<br /> *<br /> * @param num<br /> * 数字<br /> * @param fixdlenth<br /> * 字符串长度<br /> * @return 定长的字符串<br /> */<br /> public static String toFixdLengthString(int num, int fixdlenth) {<br /> StringBuilder sb = new StringBuilder();<br /> String strNum = String.valueOf(num);<br /> if (fixdlenth - strNum.length() >= 0) {<br /> sb.append(generateZeroString(fixdlenth - strNum.length()));<br /> } else {<br /> throw new RuntimeException("将数字" + num + "转化为长度为" + fixdlenth<br /> + "的字符串发生异常！");<br /> }<br /> sb.append(strNum);<br /> return sb.toString();<br /> }</p> <p> public static void main(String[] args) {<br /> System.out.println(generateString(15));<br /> System.out.println(generateMixString(15));<br /> System.out.println(generateLowerString(15));<br /> System.out.println(generateUpperString(15));<br /> System.out.println(generateZeroString(15));<br /> System.out.println(toFixdLengthString(123, 15));<br /> System.out.println(toFixdLengthString(123L, 15));<br /> }<br /> }