helloworld.java

来自「一个java的ETL工具」· Java 代码 · 共 66 行

import java.util.Hashtable;
import java.util.StringTokenizer;

public class HelloWorld
{
	public HelloWorld()
	{
		
		System.out.println("hello world");

	//	Integer I = new Integer(null);
		
		Hashtable ht = new Hashtable();

String q = null;

System.out.println("1");
		StringTokenizer st = new StringTokenizer(q, ",");
System.out.println("2");

//		System.out.println(st.countTokens());

String s = "hello" + q;
System.out.println(s);
		
		
		Object o = new Object();
		
		if (o == null) System.out.println("is null");
		
		ht.put("a", o);
System.out.println("1");		
		Object obj = ht.get("a");
System.out.println("2");		
		
		Object b = new Object();
System.out.println("3");		
		
		if (obj.equals(b)) System.out.println("obj is null");
System.out.println("4");		
		
		
//		String s = (String)ht.get("a");
		
		System.out.println("It Worked");


//		ht.put(null,"a");
//		ht.put("a",new Integer(null));
		
//		ht.put("a",new Object());
/*		
		Object a_ = ht.get("a");
		if ( a_.equals(new Object()) )
			System.out.println("is null");
		else	
			System.out.println("is NOT null");
*/

	}
	
	public static void main(String args[])
	{
		HelloWorld hw = new HelloWorld();
	}	
}