Question

/** traversing elements */
import java.util.*;  
class Traversor extends Thread
{
Enumeration e;
public Traversor(Enumeration e) 
{
this.e=e;
}
public void run()
{
System.out.println("new thread started, traversing vector  elements.....");
while(e.hasMoreElements())
{
System.out.println(e.nextElement());
try
{
Thread.sleep(4000);
}
catch(Exception ex)
{}
}

System.out.println("new thread completed");
}
}


class vectortest{  
public static void main(String args[])
{
System.out.println("main thread started, creating vector...");
Vector v=new Vector();
v.addElement("one");
v.add("three"); 
v.add(1,"two");

Enumeration e=v.elements();
System.out.println("vector created ,enumeration obtained");
Traversor th=new Traversor(e);
th.start();
System.out.println(" new thread launched , suspending main thread");

try{
Thread.sleep(1000);
 }
catch(Exception ex)
{}
System.out.println("main thread resumed,modifying vector");
v.add("four");
v.add("five");
System.out.println("vector modified, main thread completed");
}
}

Answer 1

Java引入（相当晚）将Vector Object的{{1}}集合项列为Vector<T>，其中T是给定的类型参数，如{{1} }。（它被称为泛型类型。）

现在编译器可以＆＃34;检查＆＃34;项目类型是否正常。

Vector<String>

顺便说一句，Vector和Enumeration相当古老。实际上现在很少见到Vector。

class Traversor<T> extends Thread {

    Enumeration<T> e;

    public Traversor(Enumeration<T> e) {
        this.e = e;
    }

    public void run() {
        System.out.println("new thread started, traversing vector  elements.....");
        while (e.hasMoreElements()) {
            System.out.println(e.nextElement());
            try {
                Thread.sleep(4000);
            } catch (Exception ex) {
            }
        }

        System.out.println("new thread completed");
    }
}

class VectorTest {

    public static void main(String args[]) {
        System.out.println("main thread started, creating vector...");
        Vector<String> v = new Vector<>();
        v.addElement("one");
        v.add("three");
        v.add(1, "two");

        Enumeration<String> e = v.elements();
        System.out.println("vector created ,enumeration obtained");
        Traversor<String> th = new Traversor<>(e);
        th.start();
        System.out.println(" new thread launched , suspending main thread");

        try {
            Thread.sleep(1000);
        } catch (Exception ex) {
        }
        System.out.println("main thread resumed,modifying vector");
        v.add("four");
        v.add("five");
        System.out.println("vector modified, main thread completed");
    }
}

使用-Xlint重新编译我的代码：unchecked。使用-Xlint重新编译后，将显示未选中的调用警告。我现在如何运行我的程序？

1 个答案: