diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java b/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java
index ad2a745..fba46f3 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java
@@ -1,17 +1,16 @@
 package xyz.zhouxy.plusone.commons.util;
 
+import java.security.SecureRandom;
 import java.util.Random;
 import java.util.concurrent.ThreadLocalRandom;
 
 public final class RandomTools {
 
-    private RandomTools() {
-        throw new IllegalStateException("Utility class");
-    }
+    public static final SecureRandom DEFAULT_SECURE_RANDOM = new SecureRandom();
 
-    public static String randomStr(char[] sourceCharacters, int length) {
-        return randomStr(ThreadLocalRandom.current(), sourceCharacters, length);
-    }
+    public static final String CAPITAL_LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+    public static final String LOWERCASE_LETTERS = "abcdefghijklmnopqrstuvwxyz";
+    public static final String NUMBERS = "0123456789";
 
     /**
      * 使用传入的随机数生成器，生成指定长度的字符串
@@ -24,10 +23,48 @@ public final class RandomTools {
      * @return 随机字符串
      */
     public static String randomStr(Random random, char[] sourceCharacters, int length) {
-        char[] result = new char[length];
+        final char[] result = new char[length];
         for (int i = 0; i < length; i++) {
             result[i] = sourceCharacters[random.nextInt(sourceCharacters.length)];
         }
         return String.valueOf(result);
     }
+
+    public static String randomStr(char[] sourceCharacters, int length) {
+        return randomStr(ThreadLocalRandom.current(), sourceCharacters, length);
+    }
+
+    public static String secureRandomStr(char[] sourceCharacters, int length) {
+        return randomStr(DEFAULT_SECURE_RANDOM, sourceCharacters, length);
+    }
+
+    /**
+     * 使用传入的随机数生成器，生成指定长度的字符串
+     * 
+     * @param random           随机数生成器。根据需要可以传入
+     *                         {@link java.util.concurrent.ThreadLocalRandom}、{@link java.security.SecureRandom}
+     *                         等，不为空
+     * @param sourceCharacters 字符池。字符串的字符将在数组中选，不为空
+     * @param length           字符串长度
+     * @return 随机字符串
+     */
+    public static String randomStr(Random random, String sourceCharacters, int length) {
+        final char[] result = new char[length];
+        for (int i = 0; i < length; i++) {
+            result[i] = sourceCharacters.charAt(random.nextInt(sourceCharacters.length()));
+        }
+        return String.valueOf(result);
+    }
+
+    public static String randomStr(String sourceCharacters, int length) {
+        return randomStr(ThreadLocalRandom.current(), sourceCharacters, length);
+    }
+
+    public static String secureRandomStr(String sourceCharacters, int length) {
+        return randomStr(DEFAULT_SECURE_RANDOM, sourceCharacters, length);
+    }
+
+    private RandomTools() {
+        throw new IllegalStateException("Utility class");
+    }
 }
diff --git a/src/test/java/xyz/zhouxy/plusone/commons/util/DateTimeToolsTests.java b/src/test/java/xyz/zhouxy/plusone/commons/util/DateTimeToolsTests.java
index 27db9fb..912dda6 100644
--- a/src/test/java/xyz/zhouxy/plusone/commons/util/DateTimeToolsTests.java
+++ b/src/test/java/xyz/zhouxy/plusone/commons/util/DateTimeToolsTests.java
@@ -3,10 +3,7 @@ package xyz.zhouxy.plusone.commons.util;
 import java.time.Instant;
 import java.time.LocalDateTime;
 import java.time.ZoneId;
-import org.joda.time.DateTime;
-import org.joda.time.DateTimeZone;
-import org.joda.time.format.DateTimeFormat;
-import org.joda.time.format.DateTimeFormatter;
+
 import org.junit.jupiter.api.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -37,15 +34,18 @@ class DateTimeToolsTests {
 
     @Test
     void testToJodaDateTime() {
-        DateTime jodaDateTime = DateTimeTools.toJodaDateTime(Instant.now(), ZoneId.of("+08:00"));
+        Instant now = Instant.now();
+        org.joda.time.DateTime jodaDateTime = DateTimeTools.toJodaDateTime(now, ZoneId.of("+08:00"));
+        log.info("jodaDateTime: {}", jodaDateTime);
+        jodaDateTime = DateTimeTools.toJodaDateTime(now, ZoneId.of("+02:00"));
         log.info("jodaDateTime: {}", jodaDateTime);
     }
 
     @Test
     void test() {
-        Instant now = Instant.now();
-        DateTime jodaDateTime = DateTimeTools.toJodaDateTime(now, ZoneId.of("America/New_York"));
-        DateTimeFormatter formatter = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss.SSS");
+        java.time.Instant now = java.time.Instant.now();
+        org.joda.time.DateTime jodaDateTime = DateTimeTools.toJodaDateTime(now, ZoneId.of("America/New_York"));
+        org.joda.time.format.DateTimeFormatter formatter = org.joda.time.format.DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss.SSS");
         log.info(formatter.print(jodaDateTime));
         log.info(jodaDateTime.getZone().toString());
         log.info(jodaDateTime.toString());
@@ -53,6 +53,6 @@ class DateTimeToolsTests {
         org.joda.time.Instant instant = new org.joda.time.Instant(System.currentTimeMillis() - 500000);
         log.info(instant.toString());
         log.info(DateTimeTools.toJavaInstant(instant).toString());
-        log.info(DateTimeTools.toZonedDateTime(instant, DateTimeZone.forID("America/New_York")).toString());
+        log.info(DateTimeTools.toZonedDateTime(instant, org.joda.time.DateTimeZone.forID("America/New_York")).toString());
     }
 }