diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2d4daaa64..1036cdbbe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,3 +23,4 @@
 - [fix: shutdown thread pool before the container closes](https://github.com/Tencent/spring-cloud-tencent/pull/354)
 - [rm code: Condition 'null != interceptors' is always 'true' ](https://github.com/Tencent/spring-cloud-tencent/pull/356)
 - [docs:update logo in README.](https://github.com/Tencent/spring-cloud-tencent/pull/359)
+- [Use jdk constants instead of magic variables](https://github.com/Tencent/spring-cloud-tencent/pull/362)
diff --git a/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/DecodeTransferMetadataReactiveFilter.java b/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/DecodeTransferMetadataReactiveFilter.java
index 225e3cc5d..a81b75e7f 100644
--- a/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/DecodeTransferMetadataReactiveFilter.java
+++ b/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/DecodeTransferMetadataReactiveFilter.java
@@ -20,6 +20,7 @@ package com.tencent.cloud.metadata.core;
 
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -84,7 +85,7 @@ public class DecodeTransferMetadataReactiveFilter implements WebFilter, Ordered
 				.getFirst(MetadataConstant.HeaderName.CUSTOM_METADATA);
 		try {
 			if (StringUtils.hasText(customMetadataStr)) {
-				customMetadataStr = URLDecoder.decode(customMetadataStr, "UTF-8");
+				customMetadataStr = URLDecoder.decode(customMetadataStr, StandardCharsets.UTF_8.name());
 			}
 		}
 		catch (UnsupportedEncodingException e) {
diff --git a/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/DecodeTransferMetadataServletFilter.java b/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/DecodeTransferMetadataServletFilter.java
index 8ca9e2bc2..5f7692bc7 100644
--- a/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/DecodeTransferMetadataServletFilter.java
+++ b/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/DecodeTransferMetadataServletFilter.java
@@ -21,6 +21,7 @@ package com.tencent.cloud.metadata.core;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -76,7 +77,7 @@ public class DecodeTransferMetadataServletFilter extends OncePerRequestFilter {
 		String customMetadataStr = httpServletRequest.getHeader(MetadataConstant.HeaderName.CUSTOM_METADATA);
 		try {
 			if (StringUtils.hasText(customMetadataStr)) {
-				customMetadataStr = URLDecoder.decode(customMetadataStr, "UTF-8");
+				customMetadataStr = URLDecoder.decode(customMetadataStr, StandardCharsets.UTF_8.name());
 			}
 		}
 		catch (UnsupportedEncodingException e) {
diff --git a/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataFeignInterceptor.java b/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataFeignInterceptor.java
index 0bf97bf0f..b361ee81b 100644
--- a/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataFeignInterceptor.java
+++ b/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataFeignInterceptor.java
@@ -20,6 +20,7 @@ package com.tencent.cloud.metadata.core;
 
 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
 import java.util.Map;
 
 import com.tencent.cloud.common.constant.MetadataConstant;
@@ -61,7 +62,8 @@ public class EncodeTransferMedataFeignInterceptor implements RequestInterceptor,
 			String encodedTransitiveMetadata = JacksonUtils.serialize2Json(customMetadata);
 			requestTemplate.removeHeader(CUSTOM_METADATA);
 			try {
-				requestTemplate.header(CUSTOM_METADATA, URLEncoder.encode(encodedTransitiveMetadata, "UTF-8"));
+				requestTemplate.header(CUSTOM_METADATA,
+						URLEncoder.encode(encodedTransitiveMetadata, StandardCharsets.UTF_8.name()));
 			}
 			catch (UnsupportedEncodingException e) {
 				LOG.error("Set header failed.", e);
diff --git a/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataRestTemplateInterceptor.java b/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataRestTemplateInterceptor.java
index 37f94eb2c..ce263754b 100644
--- a/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataRestTemplateInterceptor.java
+++ b/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataRestTemplateInterceptor.java
@@ -21,6 +21,7 @@ package com.tencent.cloud.metadata.core;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
 import java.util.Map;
 
 import com.tencent.cloud.common.constant.MetadataConstant;
@@ -59,7 +60,7 @@ public class EncodeTransferMedataRestTemplateInterceptor implements ClientHttpRe
 			String encodedTransitiveMetadata = JacksonUtils.serialize2Json(customMetadata);
 			try {
 				httpRequest.getHeaders().set(MetadataConstant.HeaderName.CUSTOM_METADATA,
-						URLEncoder.encode(encodedTransitiveMetadata, "UTF-8"));
+						URLEncoder.encode(encodedTransitiveMetadata, StandardCharsets.UTF_8.name()));
 			}
 			catch (UnsupportedEncodingException e) {
 				httpRequest.getHeaders().set(MetadataConstant.HeaderName.CUSTOM_METADATA, encodedTransitiveMetadata);
diff --git a/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataScgFilter.java b/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataScgFilter.java
index 81b4fba4b..b08a1072d 100644
--- a/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataScgFilter.java
+++ b/spring-cloud-starter-tencent-metadata-transfer/src/main/java/com/tencent/cloud/metadata/core/EncodeTransferMedataScgFilter.java
@@ -20,6 +20,7 @@ package com.tencent.cloud.metadata.core;
 
 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
 import java.util.Map;
 
 import com.tencent.cloud.common.constant.MetadataConstant;
@@ -67,7 +68,8 @@ public class EncodeTransferMedataScgFilter implements GlobalFilter, Ordered {
 		if (!CollectionUtils.isEmpty(customMetadata)) {
 			String metadataStr = JacksonUtils.serialize2Json(customMetadata);
 			try {
-				builder.header(MetadataConstant.HeaderName.CUSTOM_METADATA, URLEncoder.encode(metadataStr, "UTF-8"));
+				builder.header(MetadataConstant.HeaderName.CUSTOM_METADATA,
+						URLEncoder.encode(metadataStr, StandardCharsets.UTF_8.name()));
 			}
 			catch (UnsupportedEncodingException e) {
 				builder.header(MetadataConstant.HeaderName.CUSTOM_METADATA, metadataStr);
diff --git a/spring-cloud-tencent-examples/polaris-gateway-example/gateway-callee-service/src/main/java/com/tencent/cloud/polaris/gateway/example/callee/GatewayCalleeController.java b/spring-cloud-tencent-examples/polaris-gateway-example/gateway-callee-service/src/main/java/com/tencent/cloud/polaris/gateway/example/callee/GatewayCalleeController.java
index e270cdae0..eae571921 100644
--- a/spring-cloud-tencent-examples/polaris-gateway-example/gateway-callee-service/src/main/java/com/tencent/cloud/polaris/gateway/example/callee/GatewayCalleeController.java
+++ b/spring-cloud-tencent-examples/polaris-gateway-example/gateway-callee-service/src/main/java/com/tencent/cloud/polaris/gateway/example/callee/GatewayCalleeController.java
@@ -19,6 +19,7 @@ package com.tencent.cloud.polaris.gateway.example.callee;
 
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
 
 import com.tencent.cloud.common.constant.MetadataConstant;
 import org.slf4j.Logger;
@@ -63,8 +64,8 @@ public class GatewayCalleeController {
 	@RequestMapping("/echo")
 	public String echoHeader(@RequestHeader(MetadataConstant.HeaderName.CUSTOM_METADATA) String metadataStr)
 			throws UnsupportedEncodingException {
-		LOG.info(URLDecoder.decode(metadataStr, "UTF-8"));
-		return URLDecoder.decode(metadataStr, "UTF-8");
+		LOG.info(URLDecoder.decode(metadataStr, StandardCharsets.UTF_8.name()));
+		return URLDecoder.decode(metadataStr, StandardCharsets.UTF_8.name());
 	}
 
 }