小编bha*_*shi的帖子

我正在System.in使用一个用户输入java.util.Scanner.我需要验证以下内容的输入:

• 它必须是非负数
• 它必须是按字母顺序排列的字母
• ......等

最好的方法是什么？

你如何搜索一个关键HashMap？在此程序中,当用户输入密钥时,代码应安排在哈希映射中搜索相应的值,然后将其打印出来.

请告诉我为什么它不起作用.

import java.util.HashMap;

import java.util.; import java.lang.;

public class Hashmapdemo  
{
    public static void main(String args[]) 
    { 
        String value; 
        HashMap hashMap = new HashMap(); 
        hashMap.put( new Integer(1),"January" ); 
        hashMap.put( new Integer(2) ,"February" ); 
        hashMap.put( new Integer(3) ,"March" ); 
        hashMap.put( new Integer(4) ,"April" ); 
        hashMap.put( new Integer(5) ,"May" ); 
        hashMap.put( new Integer(6) ,"June" ); 
        hashMap.put( new Integer(7) ,"July" );  
        hashMap.put( new Integer(8),"August" );  
        hashMap.put( new Integer(9) ,"September");  
        hashMap.put( new Integer(10),"October" );  
        hashMap.put( new Integer(11),"November" );  
        hashMap.put( new Integer(12),"December" …

我需要使用它来合并两个有序的对象列表.

public  class ListMerge
{
   public static void main( String[] args) 
   {

      Scanner input = new Scanner(System.in);

      System.out.println ("Input length of arraylist 1:");
      int n = input.nextInt();
      ArrayList x = new ArrayList();
      ArrayList y = new ArrayList();
      for (int i = 0; i < n; i++)
      {
        System.out.println ("Input x[ " + i +"] :" );
         x.add(new Integer(i));

      }


      System.out.println ("Input length of arraylist 2:");
      int m = input.nextInt();


      for (int i = 0; i < m; i++)
      {
        System.out.println ("Input …

这是我的代码:

function validate_form(thisform)
{
with (thisform)
  {
      if (validate_required(name,"Name must be filled out!")==false)
  {name.focus();return false;}
  if (validate_required(country," Country must be filled out!")==false)
  {country.focus();return false;}
  if (validate_required(state,"State must be filled out!")==false)
  {state.focus();return false;}
  if (validate_required(city,"City must be filled out!")==false)
  {city.focus();return false;}
  if (validate_required(contact,"Contact must be filled out!")==false)
  {contact.focus();return false;}
  if (validate_required(emailid,"Email must be filled out!")==false)
  {emailid.focus();return false;}
  if (validate_email(userid,"Email is not valid")==false)
  {userid.focus();return false;}
  if (validate_required(password,"pasword must be filed out")==false)
  {password.focus();return false;}
  if (validate_required(cpassword,"Password must be confirmed")==false)
  {cpassword.focus();return false;}

if(validate_required((password.value != …

我需要应用检查,以便用户无法使用数据库中已存在的电子邮件ID进行注册.