Java 套接字 ClassCastException

Question

我一直在开发一种软件，使用 Java 套接字通过 TCP/IP 连接发送文件。程序编译，但是 'Server Application' 抛出 Class Cast Exception 并且文件没有发送到服务器。谁能帮助我，我将不胜感激。以上是以下代码：

服务器class：

package filesender;

import java.io.*;
import java.net.*;

public class ServidorTCP {

public static void main(String[] args) 
        throws IOException, UnknownHostException {

    try (ServerSocket socketServer = new ServerSocket(6789)) {
        Socket socket = socketServer.accept();
        System.out.println("Conexão realizada com o cliente na porta 6789");

        byte[] objectAsByte = new byte[socket.getReceiveBufferSize()];
        BufferedInputStream bf = 
                new BufferedInputStream(socket.getInputStream());
        bf.read(objectAsByte);

        Arquivo arquivo = (Arquivo) getObjectFromByte(objectAsByte);

        String dir = arquivo.getDiretorio() + "\" + arquivo.getNome();
        System.out.println("Criando o arquivo: " + dir);

        try (FileOutputStream fos = new FileOutputStream(dir)) {
            fos.write(arquivo.getConteudo());
        }
    }
}

private static Object getObjectFromByte(byte[] objectAsByte) {
    Object obj = null;
    ByteArrayInputStream bis = null;
    ObjectInputStream ois = null;

    try {
        bis = new ByteArrayInputStream(objectAsByte);
        ois = new ObjectInputStream(bis);
        obj = ois.read();

        bis.close();
        ois.close();
    } catch (IOException e) {

    }
    return obj;
   }
  }

客户class

package filesender;

import java.io.*;
import java.net.*;

public class ClienteTCP {

public static Arquivo arquivo;
private static final long serialVersionUID = 1L;


public static void main(String[] args) 
        throws IOException, UnknownHostException {

    selectFile();

    try (Socket clientSocket = new Socket("127.0.0.1", 6789)) {

        try (BufferedOutputStream bf = 
                new BufferedOutputStream(clientSocket.getOutputStream())) {
            byte[] bytea = serializeFile();
            bf.write(bytea);
            bf.flush();
        }
    }       
}

private static void selectFile() {      
    try {
        File file = new File("C:\Users\DeveloperEng\Documents\"
                + "teste\arquivo.txt");
        byte[] bFile = new byte[(int) file.length()];
        try (FileInputStream fis = new FileInputStream(file)) {
            fis.read(bFile);
        }


        arquivo = new Arquivo();
        arquivo.setConteudo(bFile);
        arquivo.setNome("teste.txt");
        arquivo.setDiretorio("C:\Users\DeveloperEng\Documents");
    } catch (IOException e) {

    }       
}

private static byte[] serializeFile() {
    ByteArrayOutputStream bao = null;
    ObjectOutputStream ous = null;
    try {
        bao = new ByteArrayOutputStream();
        ous = new ObjectOutputStream(bao);
        ous.writeObject(arquivo);
        //return bao.toByteArray();
    } catch (IOException e) {

    }
    return bao.toByteArray();
  }
}

文件class

package filesender;

import java.io.*;

public class Arquivo implements Serializable {
   private String nome;
   private byte[] conteudo;
   private String diretorio;

   private static final long serialVersionUID = 1L;

   public String getNome() {
      return nome;
   }

   public void setNome(String nome) {
      this.nome = nome;
   }

   public byte[] getConteudo() {
      return conteudo;
   }

   public void setConteudo(byte[] conteudo) {
      this.conteudo = conteudo;
   }

   public String getDiretorio() {
      return diretorio;
   }

   public void setDiretorio(String diretorio) {
      this.diretorio = diretorio;
   }   
}

IDE 引发的异常：

Exception in thread "main" java.lang.ClassCastException: java.lang.Integer cannot be cast to filesender.Arquivo
at filesender.ServidorTCP.main(ServidorTCP.java:20)
C:\Users\DeveloperEng\AppData\Local\NetBeans\Cache.2\executor-snippets\run.xml:53: Java returned: 1
FALHA NA CONSTRUÇÃO (tempo total: 5 segundos)

Answer 1

请参阅 ServidorTCP class 的第 20 行。您不能将 "getObjectFromByte" 方法返回的值转换为 "Archivio"，因为它不是兼容类型。特别是，它是一个整数。发生这种情况是因为 ObjectInputStream 的读取方法 returns 一个 int (See Javadoc).

Java 套接字 ClassCastException

Java Socket ClassCast Exception

java

sockets

serializable