1. import java.util.Random;
  2. import java.util.UUID;
  4. /**
  5. * 生产指定长度随机字符串a-z,A-Z,0-9
  6. * @author happyqing
  7. * @since 2016.5.30
  8. */
  9. public class RandomString {
  11. /**
  12. * 获取随机字符串 a-z,A-Z,0-9
  13. * @param length 长度
  14. * @return
  15. */
  16. public static String getRandomString(int length) {
  17. String str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  18. Random random = new Random();
  19. StringBuffer sb = new StringBuffer();
  21. for (int i = 0; i < length; ++i) {
  22. //int number = random.nextInt(62);// [0,62)
  23. sb.append(str.charAt(random.nextInt(62)));
  24. }
  25. return sb.toString();
  26. }
  28. /**
  29. * JAVA获得0-9,a-z,A-Z范围的随机数
  30. *
  31. * @param length
  32. * 随机数长度
  33. * @return String
  34. */
  35. public static String getRandomChar(int length) {
  36. char[] chr = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
  37. 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
  38. 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
  39. Random random = new Random();
  40. StringBuffer buffer = new StringBuffer();
  41. for (int i = 0; i < length; i++) {
  42. buffer.append(chr[random.nextInt(62)]);
  43. }
  44. return buffer.toString();
  45. }
  47. /**
  48. * 获取随机字符串 a-z
  49. * @param length 长度
  50. * @return
  51. */
  52. public static String getLowerLetter(int length) {
  53. String str = "abcdefghijklmnopqrstuvwxyz";
  54. Random random = new Random();
  55. StringBuffer sb = new StringBuffer();
  56. for (int i = 0; i < length; ++i) {
  57. sb.append(str.charAt(random.nextInt(26)));
  58. }
  59. return sb.toString();
  60. }
  62. /**
  63. * 获取随机字符串 0-9
  64. * @param length 长度
  65. * @return
  66. */
  67. public static String getNumber(int length) {
  68. String str = "0123456789";
  69. Random random = new Random();
  70. StringBuffer sb = new StringBuffer();
  71. for (int i = 0; i < length; ++i) {
  72. sb.append(str.charAt(random.nextInt(10)));
  73. }
  74. return sb.toString();
  75. }
  77. /**
  78. * 获取随机字符串 0-9,a-z,0-9
  79. * 有两遍0-9，增加数字概率
  80. * @param length 长度
  81. * @return
  82. */
  83. public static String getLowerLetterNumber(int length) {
  84. String str = "0123456789abcdefghijklmnopqrstuvwxyz0123456789";
  85. Random random = new Random();
  86. StringBuffer sb = new StringBuffer();
  87. for (int i = 0; i < length; ++i) {
  88. sb.append(str.charAt(random.nextInt(46)));
  89. }
  90. return sb.toString();
  91. }
  93. /**
  94. * 获取随机密码，lLength位小写英文+nLength位数字
  95. * @param lLength 字母长度
  96. * @param nLength 数字长度
  97. * @return
  98. */
  99. public static String getPasswordSimple(int lLength, int nLength) {
  100. return getLowerLetter(lLength)+getNumber(nLength);
  101. }
  103. /**
  104. * 获取随机密码，包含英文和数字
  105. * @param length 密码长度
  106. * @return
  107. */
  108. public static String getPasswordComplex(int length) {
  109. String password;
  110. while(true){
  111. password = getLowerLetterNumber(6);
  112. //必须包含字母和数字
  113. if (password.matches("(?![0-9]+$)(?![a-zA-Z]+$)[0-9A-Za-z]{6,20}")) {
  114. return password;
  115. }
  116. }
  117. }
  119. public static void main(String[] args) {
  120. // System.out.println(getRandomString(32));
  121. // System.out.println(getRandomChar(32));
  122. // //UUID
  123. // String uuid = UUID.randomUUID().toString().replaceAll("-", "");
  124. // System.out.println(uuid);
  126. System.out.println(getPasswordSimple(1,5));
  127. System.out.println(getPasswordComplex(6));
  128. }
  129. }
  130. 转自：https://www.dandelioncloud.cn/article/details/1513449489842126850