java-重写方法后无法序列化的类
作者:互联网
我在测试用例中将createSocket()方法覆盖为模拟套接字中的pas.完成此操作后,对象将不再可序列化.
这是不起作用的示例.
Foo.java
import java.io.Serializable;
public class Foo implements Serializable {
private static final long serialVersionUID = 3109852436898487119L;
public void bar() {
System.out.println("Foo");
}
}
FooTest.java
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import junit.framework.TestCase;
import org.junit.Test;
public class FooTest extends TestCase {
// this passes
@Test
public void testFooIsSerializable() throws IOException {
Foo foo = new Foo();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(baos);
out.writeObject(foo);
}
// this throws a java.io.NotSerializableException
@Test
public void testFooIsStillSerializableAfterBarIsOverridden()
throws IOException {
// Eclipse gives me the warning "The serializable class does not declare a static final serialVersionUID field of type long"
// Adding it doesn't help
Foo foo = new Foo() {
@Override
public void bar() {
System.out.println("Bar");
}
};
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(baos);
out.writeObject(foo);
}
}
使用JUnit运行FooTest时的堆栈跟踪:
java.io.NotSerializableException: FooTest
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1164)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:330)
at FooTest.testFooIsStillSerializableAfterBarIsOverridden(FooTest.java:33)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at junit.framework.TestCase.runTest(TestCase.java:168)
at junit.framework.TestCase.runBare(TestCase.java:134)
at junit.framework.TestResult$1.protect(TestResult.java:110)
at junit.framework.TestResult.runProtected(TestResult.java:128)
at junit.framework.TestResult.run(TestResult.java:113)
at junit.framework.TestCase.run(TestCase.java:124)
at junit.framework.TestSuite.runTest(TestSuite.java:232)
at junit.framework.TestSuite.run(TestSuite.java:227)
at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:83)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
这是什么问题?我必须承认,我并没有深入研究Java的Serializable接口,或多或少只是遵循Eclipse的快速修复方法.
更具体地讲我的实现:
我有一个应该通过ObjectOutputStream发送自身实例的类.
这是根本错误的方法吗?
解决方法:
问题是您有一个匿名内部类,根据定义,该内部类包含(由编译器生成的)对创建它的外部类(FooTest)的实例的引用.由于默认情况下序列化包括该对象的所有成员,因此运行时也尝试序列化FooTest对象-并且该对象不可序列化(因为它本来就不是).错误消息证明了这一点:
java.io.NotSerializableException: FooTest
因此,如果您将匿名类转换为显式的静态内部类,则该问题将消失.
标签:java,serialization,overriding 来源: https://codeday.me/bug/20191012/1896667.html