import java.util.*;
public class TestSort
{
public class void main(String [] args)
{
ArrayList al=new ArrayList();
al.add(new Integer(1));
al.add(new Integer(3));
al.add(new Integer(2));
System.out.println(al.toString());
Collection.Sort(al);
System.out.println(al.toString());
}
}
public class TestSort
{
public class void main(String [] args)
{
ArrayList al=new ArrayList();
al.add(new Integer(1));
al.add(new Integer(3));
al.add(new Integer(2));
System.out.println(al.toString());
Collection.Sort(al);
System.out.println(al.toString());
}
}
解决方案 »
- 我是新手 求解Exception in thread "main" java.lang.NoSuchMethodError: main
- 调用鼠标和键盘操作需要用到哪些类?
- 随便给一个整数,怎么找出几个素数相乘等于这个整数
- 请问java里哪个数据结构类有能让元素交换的方法?
- 如何利用java编程对oracle的数据进行导出导入?
- java程序的美观问题……
- 问一下,JTextArea框里面空白的话getText()会返回啥?
- 诸位大虾,紧急求救,一经解决马上加分(30)!
- 如何手动添加jre的注册表信息?
- 关于ArrayList扩容时的效率问题。
- java下这个函数出错了该怎么写
- static高级问题
public class TestSort
{
public static void main(String [] args) //static
{
ArrayList al=new ArrayList();
al.add(new Integer(1));
al.add(new Integer(3));
al.add(new Integer(2));
System.out.println(al.toString());
Collections.sort(al); //Collections.sort
System.out.println(al.toString());
}
}
public class TestSort
{
public class void main(String [] args) //这是什么,主函数名都写错!太晕
{
ArrayList al=new ArrayList();
al.add(new Integer(1));
al.add(new Integer(3));
al.add(new Integer(2));
System.out.println(al.toString());
Collection.Sort(al); //这是什么函数你告诉我呗!应该是Collections.sort(al)
System.out.println(al.toString());
}
}
楼主要是这么学习程序的话,那可能建议把基础打好,因为理论强,那他的实践就一定很强。
import java.util.*;
public class HashtableTest
{
public static void main(String [] args)
{
Hashtable numbers=new Hashtable();
numbers.put(new MyKey("zhang",18),new Integer(1));
numbers.put(new MyKey("lisi",16),new Integer(2));
numbers.put(new MyKey("wangwu",14),new Integer(3));
Enumeration e=numbers.keys();
while(e.hasMoreElements())
{
MyKey Key=(MyKey)e.nextElement();
System.out.println(numbers.get(Key).toString());
}
}
}
class MyKey
{
private String name;
private int age;
public MyKey(String name,int age)
{
this.name=name;
this.age=age;
}
public String toString()
{
return new String(name+","+age);
}
public boolean equals(Object obj)
{
if(name.equals(obj.name) && age==obj.age)
return true;
else
return false;
}
public int hasCode()
{
return name.hashCode()+age;
}
}