Fix AccessTokenUtil does not url encode its parameters (#40697)

* Fix bug: clientSecret not url encoded.

Author: rujche

sdk/keyvault/azure-security-keyvault-jca/src/main/java/com/azure/security/keyvault/jca/implementation/utils/AccessTokenUtil.java

@@ -6,6 +6,9 @@
 import static java.util.logging.Level.INFO;
 
 import com.azure.security.keyvault.jca.implementation.model.AccessToken;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URLEncoder;
 import java.util.HashMap;
 import java.util.logging.Logger;
 
@@ -98,10 +101,14 @@ public static AccessToken getAccessToken(String resource, String aadAuthenticati
                  .append(OAUTH2_TOKEN_POSTFIX);
 
         StringBuilder requestBody = new StringBuilder();
-        requestBody.append(GRANT_TYPE_FRAGMENT)
-                   .append(CLIENT_ID_FRAGMENT).append(clientId)
-                   .append(CLIENT_SECRET_FRAGMENT).append(clientSecret)
-                   .append(RESOURCE_FRAGMENT).append(resource);
+        try {
+            requestBody.append(GRANT_TYPE_FRAGMENT)
+                .append(CLIENT_ID_FRAGMENT).append(clientId)
+                .append(CLIENT_SECRET_FRAGMENT).append(URLEncoder.encode(clientSecret, "UTF-8"))
+                .append(RESOURCE_FRAGMENT).append(resource);
+        } catch (UnsupportedEncodingException e) {
+            LOGGER.warning("Failed to construct requestBody");
+        }
 
         String body = HttpUtil
             .post(oauth2Url.toString(), requestBody.toString(), "application/x-www-form-urlencoded");

sdk/keyvault/azure-security-keyvault-jca/src/test/java/com/azure/security/keyvault/jca/AccessTokenUtilTest.java

@@ -8,8 +8,6 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.EnabledIfEnvironmentVariable;
 
-import java.net.URLEncoder;
-
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 /**
@@ -20,11 +18,9 @@ public class AccessTokenUtilTest {
 
     /**
      * Test getAuthorizationToken method.
-     *
-     * @throws Exception when a serious error occurs.
      */
     @Test
-    public void testGetAuthorizationToken() throws Exception {
+    public void testGetAuthorizationToken() {
         String tenantId = PropertyConvertorUtils.getPropertyValue("AZURE_KEYVAULT_TENANT_ID");
         String clientId = PropertyConvertorUtils.getPropertyValue("AZURE_KEYVAULT_CLIENT_ID");
         String clientSecret = PropertyConvertorUtils.getPropertyValue("AZURE_KEYVAULT_CLIENT_SECRET");
@@ -37,7 +33,7 @@ public void testGetAuthorizationToken() throws Exception {
             aadAuthenticationUrl,
             tenantId,
             clientId,
-            URLEncoder.encode(clientSecret, "UTF-8")
+            clientSecret
         );
         assertNotNull(result);
     }