自己实现随机字符串的生成。

plusone-basic/plusone-basic-common/src/main/java/xyz/zhouxy/plusone/util/RandomUtil.java

@@ -0,0 +1,18 @@
+package xyz.zhouxy.plusone.util;
+
+import java.util.concurrent.ThreadLocalRandom;
+
+public final class RandomUtil {
+    private RandomUtil() {
+        throw new IllegalStateException("Utility class");
+    }
+
+    public static String randomStr(char[] sourceCharacters, int length) {
+        ThreadLocalRandom random = ThreadLocalRandom.current();
+        char[] result = new char[length];
+        for (int i = 0; i < length; i++) {
+            result[i] = sourceCharacters[random.nextInt(sourceCharacters.length)];
+        }
+        return String.valueOf(result);
+    }
+}