写入可序列化对象时，ObjectOutputStream.writeObject()（在 socket.getOutputStream() 之上）抛出损坏的管道（IO 异常）

Question

更新： 完整代码示例： 服务器：

ServerSocket serverSocket = new ServerSocket(8888);
Socket client = serverSocket.accept();
writer_ = new ObjectOutputStream(client.getOutputStream());
writer_.writeObject("This should be a solstice message normally.");
writer_.flush();

客户：

Socket clientSocket = new Socket(InetAddress.getLocalHost(), 8888);
ObjectInputStream reader = new ObjectInputStream(clientSocket.getInputStream());
Object obj = reader.readObject();
if (obj instanceof SolsticeMessage)
{
    SolsticeMessage message = (SolsticeMessage) obj;
    processMessage(message);
}
else
    System.out.println("Received a message of unknown type: " + obj.getClass());

当我运行代码时，客户端连接到服务器，但是它从不打印“else”分支中的 System.out.println()。此外，如果我将服务器更改如下：

ServerSocket serverSocket = new ServerSocket(8888);
Socket client = serverSocket.accept();
writer_ = new ObjectOutputStream(client.getOutputStream());
writer_.writeObject(message); // of type SolsticeMessage
writer_.flush();

写一个正确的消息，然后服务器立即抛出损坏的管道异常。

原来的问题： 我正在尝试编写一个等待客户端连接的简单服务器，如下所示：

ServerSocket serverSocket = new ServerSocket(8888);
Socket client = serverSocket.accept();
writer_ = new ObjectOutputStream(client.getOutputStream());

然后，确保 writer_ 不为空，我尝试将以下两条消息写入客户端：

writer_.writeObject("This is a string.");
writer_.writeObject(message); // where message implements Serializable
writer_.flush();

这是客户端代码：

Socket clientSocket = new Socket(InetAddress.getLocalHost(), 8888);
ObjectInputStream reader = new ObjectInputStream(clientSocket.getInputStream());
Object obj = null;
while ((obj = reader.readObject()) != null)
{
    SolsticeMessage message = (SolsticeMessage) obj;
    processMessage(message);
}

与我的预期相反（应该写入两个对象），第一个对象（字符串）发送成功，但是第二个对象（消息）抛出以下异常：

java.net.SocketException: Broken pipe
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
at java.io.ObjectOutputStream$BlockDataOutputStream.drain(ObjectOutputStream.java:1847)
at java.io.ObjectOutputStream$BlockDataOutputStream.setBlockDataMode(ObjectOutputStream.java:1756)
at java.io.ObjectOutputStream.writeNonProxyDesc(ObjectOutputStream.java:1257)
at java.io.ObjectOutputStream.writeClassDesc(ObjectOutputStream.java:1211)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1395)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
at java.io.ObjectOutputStream.writeFatalException(ObjectOutputStream.java:1547)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:333)
at com.kivancmuslu.www.solstice.server.SolsticeServer.sendMessage(SolsticeServer.java:146)
at com.kivancmuslu.www.solstice.server.listeners.ResourceChangeListener.processResourceChange(ResourceChangeListener.java:94)
at com.kivancmuslu.www.solstice.server.listeners.ResourceChangeListener.processResourceDelta(ResourceChangeListener.java:65)
at com.kivancmuslu.www.solstice.server.listeners.ResourceChangeListener.processResourceDelta(ResourceChangeListener.java:86)
at com.kivancmuslu.www.solstice.server.listeners.ResourceChangeListener.processResourceDelta(ResourceChangeListener.java:86)
at com.kivancmuslu.www.solstice.server.listeners.ResourceChangeListener.processResourceDelta(ResourceChangeListener.java:86)
at com.kivancmuslu.www.solstice.server.listeners.ResourceChangeListener.resourceChanged(ResourceChangeListener.java:31)
at org.eclipse.core.internal.events.NotificationManager$1.run(NotificationManager.java:291)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.NotificationManager.notify(NotificationManager.java:285)
at org.eclipse.core.internal.events.NotificationManager.broadcastChanges(NotificationManager.java:149)
at org.eclipse.core.internal.resources.Workspace.broadcastPostChange(Workspace.java:395)
at org.eclipse.core.internal.resources.Workspace.endOperation(Workspace.java:1530)
at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:156)
at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:241)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)

任何想法为什么字符串对象被写入并通过网络发送而没有问题，但是我的其他序列化对象导致此异常？我还在下面附上了我的序列化类，以防万一：

package com.kivancmuslu.www.solstice.logic;

public class ResourceChangedMessage extends SolsticeMessage
{
    /**
     * 
     */
    private static final long serialVersionUID = -2877650023886033398L;

    public static enum ResourceChangeType
    {
        ADDED, REMOVED
    }

    private final String projectName_;
    private final String relativeResourcePath_;
    private final ResourceChangeType resourceChangeType_;

    public ResourceChangedMessage(String projectName, String relativeResourcePath,
                                  ResourceChangeType resourceChangeType)
    {
        projectName_ = projectName;
        relativeResourcePath_ = relativeResourcePath;
        resourceChangeType_ = resourceChangeType;
    }

    public String getProjectName()
    {
        return projectName_;
    }

    public String getRelativeResourcePath()
    {
        return relativeResourcePath_;
    }

    public ResourceChangeType getResourceChangeType()
    {
        return resourceChangeType_;
    }
}

其中 SolsticeMessage 定义为：

package com.kivancmuslu.www.solstice.logic;

import java.io.Serializable;

public abstract class SolsticeMessage implements Serializable
{
    private static final long serialVersionUID = 4048501241385740686L;

    public abstract String toString();
}

谢谢你，

Answer 1

我强烈怀疑连接的另一端正在关闭它。例如，如果它是另一个具有以下代码的 Java 程序：

Socket client = serverSocket.accept();
reader_ = new ObjectInputStream(client.getInputStream());
reader_.readObject();
reader_.close();

...那么您的发送代码将无处可发送第二个对象。不幸的是，你没有给我们正在监听的代码。以上是我最好的猜测。

编辑：现在您已经发布了服务器代码，我们可以看到真正的问题。这是它试图阅读的内容：

while ((obj = reader.readObject()) != null)
{
    SolsticeMessage message = (SolsticeMessage) obj;
    processMessage(message);
}

...但您首先要发送String。所以它试图将String 转换为SolsticeMessage，这将引发异常 - 并且可能 会导致整个过程停止，或者至少以关闭的连接结束。