广州面试题------百胜软件

桃扇骨 2022-05-21 23:34 174阅读 0赞

![70][]![70 1][]![70 2][]![70 3][]

部分面试题答案：

1、  
ArrayList和LinkedList都间接的实现了List接口，都不是线程安全的(Vector是线程安全的)。  
ArrayList和Vector底层是基于数组结构，而LinkedList底层是基于链表(双链表)结构。  
ArrayList的查询修改快，LinkedList的增删速度快。  
ArrayList扩容是增长原来的一半(Vector是增长原来的2倍)，LinkedList是基于节点来扩容的。  
ArrayList初始化容量大小是10，vector初始化容量也是10。  
  
  
2、  
  
public class ManyThreads \{  
  
    private int j;  
  
    public static void main(String\[\] args) \{  
        // TODO Auto-generated method stub  
        ManyThreads many = new ManyThreads();  
        Inc inc = many.new Inc();  
        Dec dec = many.new Dec();  
        for (int i = 0; i < 2; i++) \{  
            Thread t = new Thread(inc);  
            t.start();  
            t = new Thread(dec);  
            t.start();  
        \}  
    \}  
  
    private synchronized void inc() \{  
        j++;  
        System.out.println(Thread.currentThread().getName() + "inc" + j);  
    \}  
  
    private synchronized void dec() \{  
        j--;  
        System.out.println(Thread.currentThread().getName() + "dec" + j);  
    \}  
  
    class Inc implements Runnable \{  
  
        @Override  
        public void run() \{  
            // TODO Auto-generated method stub  
            for (int i = 0; i < 20; i++) \{  
                inc();  
            \}  
        \}  
  
    \}  
  
    class Dec implements Runnable \{  
  
        @Override  
        public void run() \{  
            // TODO Auto-generated method stub  
            for (int i = 0; i < 20; i++) \{  
                dec();  
            \}  
        \}  
  
    \}  
      
      
  
4. 服务端：  
public class Server \{  
public static void main(String\[\] args) \{  
    BufferedReader bReader=null;  
    PrintWriter pWriter=null;  
    try \{  
        ServerSocket server = new ServerSocket(2000);  
        Socket socket = server.accept();  
        //获取输入流  
        bReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));  
        //获取输出流  
        pWriter = new PrintWriter(socket.getOutputStream(),true);  
        //获取接收的数据  
        String string= bReader.readLine();  
        //发送相同的数据给客户端  
        pWriter.println(string);  
    \} catch (Exception e) \{  
        // TODO: handle exception  
        e.printStackTrace();  
    \}finally \{  
        try \{  
            bReader.close();  
            pWriter.close();  
        \} catch (Exception e2) \{  
            // TODO: handle exception  
        \}  
    \}  
\}  
\}  
      
    客户端：public class Client \{  
    public static void main(String\[\] args) \{  
        BufferedReader brc = null;  
        PrintWriter pwc = null;  
        try \{  
            Socket socket = new Socket("127.0.0.1",2000);  
            brc = new BufferedReader(new InputStreamReader(socket.getInputStream()));  
            pwc = new PrintWriter(socket.getOutputStream(),true);  
            pwc.println("Hello");  
            String sc = null;  
            while (true) \{  
                sc = brc.readLine();  
                if (sc!=null) \{  
                    break;  
                \}  
            \}  
            System.out.println(sc);  
        \} catch (Exception e) \{  
            // TODO: handle exception  
            e.printStackTrace();  
        \}finally \{  
            try \{  
                brc.close();  
                pwc.close();  
            \} catch (IOException e) \{  
                // TODO Auto-generated catch block  
                e.printStackTrace();  
            \}  
  
        \}  
    \}  
  
\}  
      
      
5、  
servlet的生命周期分为三个阶段：初始化阶段，调用init()方法，响应客户请求阶段 调用service()方法，销毁阶段 调用destroy()方法  
  
6、  
有状态会话session Bean实例有三种状态，不存在，就绪，和钝化。Entitybean有三种状态，不存在，在pool中，就绪

[70]: https://img-blog.csdn.net/20180611093722390?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyOTM5Njc5/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 1]: https://img-blog.csdn.net/20180611093748888?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyOTM5Njc5/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 2]: https://img-blog.csdn.net/20180611093805615?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyOTM5Njc5/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 3]: /images/20220522/88498a79805646a5874b8f7f77ec63cd.png