diff --git a/unknow-server-servlet/src/main/java/unknow/server/servlet/http2/Http2Headers.java b/unknow-server-servlet/src/main/java/unknow/server/servlet/http2/Http2Headers.java
index 1a9e2d7..6ad6919 100644
--- a/unknow-server-servlet/src/main/java/unknow/server/servlet/http2/Http2Headers.java
+++ b/unknow-server-servlet/src/main/java/unknow/server/servlet/http2/Http2Headers.java
@@ -247,10 +247,16 @@ private static String readData(InputStream in) throws IOException {
 
 	private static void writeData(Buffers out, String value) throws InterruptedException {
 		byte[] bytes = value.getBytes(StandardCharsets.US_ASCII);
-		// TODO huffman
 
-		writeInt(out, 0, 7, bytes.length);
-		out.write(bytes);
+		Buffers b = new Buffers();
+		Http2Huffman.encode(b, bytes);
+		if (b.length() < bytes.length) {
+			writeInt(out, 0x80, 7, b.length());
+			b.read(out, -1, false);
+		} else {
+			writeInt(out, 0, 7, bytes.length);
+			out.write(bytes);
+		}
 	}
 
 	protected Entry get(int i) {
diff --git a/unknow-server-servlet/src/main/java/unknow/server/servlet/http2/Http2Huffman.java b/unknow-server-servlet/src/main/java/unknow/server/servlet/http2/Http2Huffman.java
index 7c6e144..fd8441e 100644
--- a/unknow-server-servlet/src/main/java/unknow/server/servlet/http2/Http2Huffman.java
+++ b/unknow-server-servlet/src/main/java/unknow/server/servlet/http2/Http2Huffman.java
@@ -4,6 +4,8 @@
 import java.io.IOException;
 import java.io.InputStream;
 
+import unknow.server.util.io.Buffers;
+
 /**
  * HPACK static huffman table
  * https://httpwg.org/specs/rfc7541.html#huffman.code
@@ -37,6 +39,29 @@ public class Http2Huffman {
 			10, 13, 22, 256 // 29, 30
 	};
 
+	private static final int[] codes = { 0x1ff8, 0x7fffd8, 0xfffffe2, 0xfffffe3, 0xfffffe4, 0xfffffe5, 0xfffffe6, 0xfffffe7, 0xfffffe8, 0xffffea, 0x3ffffffc, 0xfffffe9,
+			0xfffffea, 0x3ffffffd, 0xfffffeb, 0xfffffec, 0xfffffed, 0xfffffee, 0xfffffef, 0xffffff0, 0xffffff1, 0xffffff2, 0x3ffffffe, 0xffffff3, 0xffffff4, 0xffffff5,
+			0xffffff6, 0xffffff7, 0xffffff8, 0xffffff9, 0xffffffa, 0xffffffb, 0x14, 0x3f8, 0x3f9, 0xffa, 0x1ff9, 0x15, 0xf8, 0x7fa, 0x3fa, 0x3fb, 0xf9, 0x7fb, 0xfa, 0x16,
+			0x17, 0x18, 0x0, 0x1, 0x2, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x5c, 0xfb, 0x7ffc, 0x20, 0xffb, 0x3fc, 0x1ffa, 0x21, 0x5d, 0x5e, 0x5f, 0x60, 0x61, 0x62,
+			0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0xfc, 0x73, 0xfd, 0x1ffb, 0x7fff0, 0x1ffc, 0x3ffc, 0x22, 0x7ffd,
+			0x3, 0x23, 0x4, 0x24, 0x5, 0x25, 0x26, 0x27, 0x6, 0x74, 0x75, 0x28, 0x29, 0x2a, 0x7, 0x2b, 0x76, 0x2c, 0x8, 0x9, 0x2d, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7ffe, 0x7fc,
+			0x3ffd, 0x1ffd, 0xffffffc, 0xfffe6, 0x3fffd2, 0xfffe7, 0xfffe8, 0x3fffd3, 0x3fffd4, 0x3fffd5, 0x7fffd9, 0x3fffd6, 0x7fffda, 0x7fffdb, 0x7fffdc, 0x7fffdd, 0x7fffde,
+			0xffffeb, 0x7fffdf, 0xffffec, 0xffffed, 0x3fffd7, 0x7fffe0, 0xffffee, 0x7fffe1, 0x7fffe2, 0x7fffe3, 0x7fffe4, 0x1fffdc, 0x3fffd8, 0x7fffe5, 0x3fffd9, 0x7fffe6,
+			0x7fffe7, 0xffffef, 0x3fffda, 0x1fffdd, 0xfffe9, 0x3fffdb, 0x3fffdc, 0x7fffe8, 0x7fffe9, 0x1fffde, 0x7fffea, 0x3fffdd, 0x3fffde, 0xfffff0, 0x1fffdf, 0x3fffdf,
+			0x7fffeb, 0x7fffec, 0x1fffe0, 0x1fffe1, 0x3fffe0, 0x1fffe2, 0x7fffed, 0x3fffe1, 0x7fffee, 0x7fffef, 0xfffea, 0x3fffe2, 0x3fffe3, 0x3fffe4, 0x7ffff0, 0x3fffe5,
+			0x3fffe6, 0x7ffff1, 0x3ffffe0, 0x3ffffe1, 0xfffeb, 0x7fff1, 0x3fffe7, 0x7ffff2, 0x3fffe8, 0x1ffffec, 0x3ffffe2, 0x3ffffe3, 0x3ffffe4, 0x7ffffde, 0x7ffffdf,
+			0x3ffffe5, 0xfffff1, 0x1ffffed, 0x7fff2, 0x1fffe3, 0x3ffffe6, 0x7ffffe0, 0x7ffffe1, 0x3ffffe7, 0x7ffffe2, 0xfffff2, 0x1fffe4, 0x1fffe5, 0x3ffffe8, 0x3ffffe9,
+			0xffffffd, 0x7ffffe3, 0x7ffffe4, 0x7ffffe5, 0xfffec, 0xfffff3, 0xfffed, 0x1fffe6, 0x3fffe9, 0x1fffe7, 0x1fffe8, 0x7ffff3, 0x3fffea, 0x3fffeb, 0x1ffffee, 0x1ffffef,
+			0xfffff4, 0xfffff5, 0x3ffffea, 0x7ffff4, 0x3ffffeb, 0x7ffffe6, 0x3ffffec, 0x3ffffed, 0x7ffffe7, 0x7ffffe8, 0x7ffffe9, 0x7ffffea, 0x7ffffeb, 0xffffffe, 0x7ffffec,
+			0x7ffffed, 0x7ffffee, 0x7ffffef, 0x7fffff0, 0x3ffffee };
+
+	private static final int[] sizes = { 13, 23, 28, 28, 28, 28, 28, 28, 28, 24, 30, 28, 28, 30, 28, 28, 28, 28, 28, 28, 28, 28, 30, 28, 28, 28, 28, 28, 28, 28, 28, 28, 6, 10,
+			10, 12, 13, 6, 8, 11, 10, 10, 8, 11, 8, 6, 6, 6, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 8, 15, 6, 12, 10, 13, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+			7, 7, 7, 8, 7, 8, 13, 19, 13, 14, 6, 15, 5, 6, 5, 6, 5, 6, 6, 6, 5, 7, 7, 6, 6, 6, 5, 6, 7, 6, 5, 5, 6, 7, 7, 7, 7, 7, 15, 11, 14, 13, 28, 20, 22, 20, 20, 22, 22,
+			22, 23, 22, 23, 23, 23, 23, 23, 24, 23, 24, 24, 22, 23, 24, 23, 23, 23, 23, 21, 22, 23, 22, 23, 23, 24, 22, 21, 20, 22, 22, 23, 23, 21, 23, 22, 22, 24, 21, 22, 23,
+			23, 21, 21, 22, 21, 23, 22, 23, 23, 20, 22, 22, 22, 23, 22, 22, 23, 26, 26, 20, 19, 22, 23, 22, 25, 26, 26, 26, 27, 27, 26, 24, 25, 19, 21, 26, 27, 27, 26, 27, 24,
+			21, 21, 26, 26, 28, 27, 27, 27, 20, 24, 20, 21, 22, 21, 21, 23, 22, 22, 25, 25, 24, 24, 26, 23, 26, 27, 26, 26, 27, 27, 27, 27, 27, 28, 27, 27, 27, 27, 27, 26 };
+
 	private Http2Huffman() {
 	}
 
@@ -71,6 +96,33 @@ public static String decode(InputStream b, int max, StringBuilder sb) throws IOE
 		return sb.toString();
 	}
 
+	public static void encode(Buffers b, byte[] data) throws InterruptedException {
+		C c = new C();
+		for (int i = 0; i < data.length; i++)
+			encode(c, b, data[i]);
+		if (c.cnt != 0)
+			b.write(c.bit | (0xff >> c.cnt));
+	}
+
+	private static void encode(C c, Buffers buf, byte b) throws InterruptedException {
+		int code = codes[b];
+		int size = sizes[b];
+
+		while (size > 0) {
+			int r = 8 - c.cnt;
+			if (size <= r) {
+				c.cnt += size;
+				c.bit |= (code << (r - size)) & 0xFF;
+				return;
+			}
+
+			size -= r;
+			buf.write(c.bit | (code >> size) & 0xFF);
+			c.bit = 0;
+			c.cnt = 0;
+		}
+	}
+
 	private static final char read(S s) throws IOException {
 		int first = 0; /* first code of length len */
 		int index = 0; /* index of first code of length len in symbol table */
@@ -97,12 +149,14 @@ private static final char read(S s) throws IOException {
 		}
 	}
 
-	static final class S {
-		final InputStream b;
-		int max;
-
+	static class C {
 		int bit;
 		int cnt;
+	}
+
+	static class S extends C {
+		final InputStream b;
+		int max;
 
 		public S(InputStream b, int max) {
 			this.b = b;
diff --git a/unknow-server-servlet/src/test/java/unknow/server/servlet/http2/Http2HuffmanTest.java b/unknow-server-servlet/src/test/java/unknow/server/servlet/http2/Http2HuffmanTest.java
new file mode 100644
index 0000000..060f942
--- /dev/null
+++ b/unknow-server-servlet/src/test/java/unknow/server/servlet/http2/Http2HuffmanTest.java
@@ -0,0 +1,53 @@
+package unknow.server.servlet.http2;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import unknow.server.util.io.Buffers;
+import unknow.server.util.io.BuffersUtils;
+
+public class Http2HuffmanTest {
+	public static Stream<Arguments> input() {
+		//@formatter:off
+		return Stream.of(
+				Arguments.of("www.example.com", new byte[] { b(0xf1), b(0xe3), b(0xc2), b(0xe5), b(0xf2), b(0x3a), b(0x6b), b(0xa0), b(0xab), b(0x90), b(0xf4), b(0xff) }),
+				Arguments.of("no-cache", new byte[]{b(0xa8),b(0xeb),b(0x10),b(0x64),b(0x9c),b(0xbf)}),
+				Arguments.of("custom-key", new byte[]{b(0x25),b(0xa8),b(0x49),b(0xe9),b(0x5b),b(0xa9),b(0x7d),b(0x7f)}),
+				Arguments.of("custom-value", new byte[]{b(0x25),b(0xa8),b(0x49),b(0xe9),b(0x5b),b(0xb8),b(0xe8),b(0xb4),b(0xbf)})
+				); //@formatter:on
+	}
+
+	@ParameterizedTest
+	@MethodSource("input")
+	public void decode(String decoded, byte[] encoded) throws IOException {
+		StringBuilder sb = new StringBuilder();
+		try (InputStream b = new ByteArrayInputStream(encoded)) {
+			Http2Huffman.decode(b, encoded.length, sb);
+		}
+		assertEquals(decoded, sb.toString());
+	}
+
+	@ParameterizedTest
+	@MethodSource("input")
+	public void encode(String decoded, byte[] encoded) throws InterruptedException {
+		byte[] bytes = decoded.getBytes(StandardCharsets.US_ASCII);
+		Buffers b = new Buffers();
+		Http2Huffman.encode(b, bytes);
+		byte[] array = BuffersUtils.toArray(b, 0, -1);
+		assertArrayEquals(encoded, array);
+	}
+
+	public static final byte b(int i) {
+		return (byte) (i & 0xFF);
+	}
+}