无法从反序列化还原动态创建的类

Question

我有一个动态创建的字符串格式的类：

private String demoClassString = "import java.io.Serializable;\n" +
                    "public class DemoClass implements Serializable{\n" +
                    "\tpublic String getResult(Integer a){\n" +
                    "\t\treturn \"Result is \"+a;\n" +
                    "\t}\n" +
                    "\n" +
                    "}";

我只想编译一次，然后将其编译后的类对象保存在持久性存储中（我用文件对其进行了测试，但最终将存储在DB中）

我使用Janino Compiler

测试方案如下：

@Test
public void testSaveFormulaWithJanino() throws Exception {
   final String className = "DemoClass";

   SimpleCompiler sc = new SimpleCompiler();
   sc.cook(demoClassString);

   Class<?> demoClass = sc.getClassLoader().loadClass(className);
   testDemoClass(demoClass, "getResult");

   byte[] serialized = SerializationUtils.serialize(demoClass);
   logger.info("Serialized with SerializationUtils  size = "+serialized.length);

   Object deserializedClass = SerializationUtils.deserialize(serialized);
   testDemoClass((Class<?>)deserializedClass, "getResult");
   saveObject(demoClass);
}

testdemoClass方法以反射方式调用动态创建的对象的getResult方法：

   private void testDemoClass(Class<?> demoClass, String methodName) {
        try {
            Object deSerializedObject = demoClass.newInstance();
            Method doWork = deSerializedObject.getClass().getDeclaredMethod(methodName, Integer.class);
            Integer param = 15;
            Object result = doWork.invoke(deSerializedObject, param);
            logger.info("Database object method invocation with reflection, result is = " + result);
            assertTrue(true);
        } catch (Exception e) {
            fail();
        }
    }

此测试的结果如下：

Database object method invocation with reflection, result is = Result is 15
Serialized with SerializationUtils  byte[] size = 30



org.apache.commons.lang3.SerializationException: java.lang.ClassNotFoundException: DemoClass

    at org.apache.commons.lang3.SerializationUtils.deserialize(SerializationUtils.java:229)
    at org.apache.commons.lang3.SerializationUtils.deserialize(SerializationUtils.java:267)
    at com.intrasoft.ssp.testing.formulas.FormulaCompilationFileTest.testSaveFormulaWithJanino(FormulaCompilationFileTest.java:115)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.lang.ClassNotFoundException: DemoClass
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:686)
    at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1866)
    at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1749)
    at java.io.ObjectInputStream.readClass(ObjectInputStream.java:1714)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1554)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:431)
    at org.apache.commons.lang3.SerializationUtils.deserialize(SerializationUtils.java:223)
    ... 24 more

为什么classLoader找不到之前已成功加载2条语句的类？