回文数-时间变换-判断邮箱

class huiwenshu

public class huiwenshu {
    public static void main(String[] args) {
    	System.out.println("输入...");
    	  Scanner in = new Scanner(System.in);
    	  String number = in.next();
    	  boolean flag = true;
    	  for(int i=0;i<number.trim().length()/2;i++){

    	    if(!String.valueOf(number.charAt(i)).equals(String.valueOf(number.charAt(number.trim().length()-i-1)))){
    	    flag = false;
    	    break;
    	   }
    	  }
    	  if(flag){
    	   System.out.println("是滴");
    	  }else{
    	   System.out.println("no go away");
    	  }
    	  in.close();

	}
}

　　/class ChangeTime

package 时间变换;

import java.util.Date;
import java.util.TimeZone;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;

public class ChangeTime {
    public static void main(String[] args) throws ParseException {
    	Date date=new Date();
    	SimpleDateFormat sdf3=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		sdf3.setTimeZone(TimeZone.getTimeZone("GMT+8"));
		System.out.println("beijig"+sdf3.format(date));

		SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		sdf.setTimeZone(TimeZone.getTimeZone("GMT+1"));
		System.out.println("bali"+sdf.format(date));
		SimpleDateFormat sdf1=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		sdf1.setTimeZone(TimeZone.getTimeZone("GMT-4"));
		System.out.println("niuyue"+sdf1.format(date));
	}
    public void getTime(int year,int month,int date,int h,int m){
		Calendar c = Calendar.getInstance();
		//设置巴黎的时间
		c.set(year, month, date, h-7, m);
		System.out.println("巴黎时间："+c.get(Calendar.YEAR)+"年"+c.get(Calendar.MONTH)
		+"月"+c.get(Calendar.DAY_OF_MONTH)+"日"+c.get(Calendar.HOUR_OF_DAY)+"点"+
				c.get(Calendar.MINUTE)+"分");
		//设置纽约时间
		c.set(year, month, date, h-12, m);
		System.out.println("纽约时间："+c.get(Calendar.YEAR)+"年"+c.get(Calendar.MONTH)
				+"月"+c.get(Calendar.DAY_OF_MONTH)+"日"+c.get(Calendar.HOUR_OF_DAY)+"点"+
						c.get(Calendar.MINUTE)+"分");
	}

}

　　/class Demo

package 解析邮箱;

import java.util.Scanner;

public class Demo {
	public boolean testEmail(){
		System.out.println("请输入一个邮箱~~~");
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		if(s.indexOf("@")==-1||s.indexOf(".")==-1){
			System.out.println("邮箱没有@或.");
			return false;
		}
		if(s.indexOf("@")!=s.lastIndexOf("@")||s.indexOf(".")!=s.lastIndexOf(".")){
			System.out.println("邮箱中含有多个@或.");
			return false;
		}
		if(s.indexOf("@")>s.indexOf(".")){
			System.out.println("邮箱中的.出现在@前面");

		}
		for (int i = 0; i < s.indexOf("@"); i++) {
			if((s.charAt(i)>=‘a‘&&s.charAt(i)<=‘z‘)||(s.charAt(i)>=‘A‘&&s.charAt(i)<=‘Z‘)){

			}else{
				System.out.println("用户名含有其他字符");
				return false;
			}
		}
		return true;

	}

	public static void main(String[] args) {
		Demo d = new Demo();
		if(d.testEmail()){
			System.out.println("用户名合法");

		}else {
			System.out.println("用户名不合法");
		}

	}

}