优化MD5性能

hutool-crypto/src/test/java/cn/hutool/crypto/digest/Md5Test.java

@@ -1,5 +1,7 @@
 package cn.hutool.crypto.digest;
 
+import cn.hutool.core.io.IoUtil;
+import cn.hutool.core.thread.ConcurrencyTester;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -17,4 +19,15 @@ public class Md5Test {
 		Assert.assertEquals(16, hex16.length());
 		Assert.assertEquals("cb143acd6c929826", hex16);
 	}
+
+	@Test
+	public void md5ThreadSafeTest() {
+		final String text = "Hutool md5 test str";
+		final ConcurrencyTester tester = new ConcurrencyTester(1000);
+		tester.test(()->{
+			final String digest = new MD5().digestHex(text);
+			Assert.assertEquals("8060075dd8df47bac3247438e940a728", digest);
+		});
+		IoUtil.close(tester);
+	}
 }