修复URLUtil.decode无法解码UTF-16问题

hutool-core/src/test/java/cn/hutool/core/net/UrlDecoderTest.java

@@ -1,12 +1,42 @@
 package cn.hutool.core.net;
 
 import cn.hutool.core.util.CharsetUtil;
+import cn.hutool.core.util.URLUtil;
 import org.junit.Assert;
 import org.junit.Test;
 
+import java.io.UnsupportedEncodingException;
+import java.nio.charset.StandardCharsets;
+
 public class UrlDecoderTest {
 	@Test
 	public void decodeForPathTest(){
 		Assert.assertEquals("+", URLDecoder.decodeForPath("+", CharsetUtil.CHARSET_UTF_8));
 	}
+
+	@Test
+	public void issue3063Test() throws UnsupportedEncodingException {
+		// https://github.com/dromara/hutool/issues/3063
+
+		final String s = "测试";
+		final String expectedDecode = "%FE%FF%6D%4B%8B%D5";
+
+		final String s1 = URLUtil.encode(s, StandardCharsets.UTF_16);
+		Assert.assertEquals(expectedDecode, s1);
+		final String s2 = java.net.URLEncoder.encode(s, "UTF-16");
+		Assert.assertEquals(expectedDecode, s2);
+
+		final String decode = URLDecoder.decode(s1, StandardCharsets.UTF_16);
+		Assert.assertEquals(s, decode);
+
+		// 测试编码字符串和非编码字符串混合
+		final String mixDecoded = expectedDecode + "你好";
+		final String decode2 = URLDecoder.decode(mixDecoded, StandardCharsets.UTF_16);
+		Assert.assertEquals("测试你好", decode2);
+
+		Assert.assertEquals(
+			java.net.URLDecoder.decode(mixDecoded, "UTF-16"),
+			URLDecoder.decode(mixDecoded, StandardCharsets.UTF_16)
+		);
+	}
 }