add Text.randomPassword

src/main/java/com/imyeyu/utils/Text.java

@@ -165,11 +165,31 @@ public class Text {
 		SecureRandom r = new SecureRandom();
 		StringBuilder sb = new StringBuilder();
 		for (int i = 0; i < length; i++) {
-			sb.append(pool.charAt(r.nextInt(pool.length() - 1)));
+			sb.append(pool.charAt(r.nextInt(pool.length())));
 		}
 		return sb.toString();
 	}
 
+	public static String randomPassword(int length) {
+		if (length < 6 || 32 < length) {
+			throw new IllegalArgumentException("Password length must be between 6 and 32");
+		}
+		SecureRandom r = new SecureRandom();
+		char[] chars = new char[length];
+		chars[0] = LETTER_POOL.charAt(r.nextInt(LETTER_POOL.length()));
+		chars[1] = NUMBER_POOL.charAt(r.nextInt(NUMBER_POOL.length()));
+		for (int i = 2; i < length; i++) {
+			chars[i] = PASSWORD_CHAR_POOL.charAt(r.nextInt(PASSWORD_CHAR_POOL.length()));
+		}
+		for (int i = chars.length - 1; 0 < i; i--) {
+			int j = r.nextInt(i + 1);
+			char temp = chars[i];
+			chars[i] = chars[j];
+			chars[j] = temp;
+		}
+		return new String(chars);
+	}
+
 	/**
 	 * 较短的临时 UUID，如果使用在庞大的数据里，很可能会发生重复
 	 *