Java:1.正则表达式验证电子邮箱的合法性；2.将字符串里的数字排序后再以字符串形式输出；3.按格式输出时间。

1.正则表达式验证电子邮箱的合法性

import java.util.Scanner;

public class EmailTest {
    
    
    public static void main(String[] args) {
    
    
        String EmailRegex = "^\\w+((-\\w+)|(\\.\\w+))*\\@[A-Za-z0-9]+((\\.|-)[A-Za-z0-9]+)*\\.[A-Za-z0-9]+$";
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入邮箱号：");
        String s = scanner.next();
        boolean b = s.matches(EmailRegex);
        if (b == false) {
    
    
            System.out.println("邮箱名不符合规则！");
        } else {
    
    
            System.out.println("邮箱名符合规则！");
        }
    }
}

2.将字符串里的数字排序后再以字符串形式输出

import java.util.Arrays;

public class NumberSort {
    
    
    public static void main(String[] args) {
    
    
        String s1 = "91 27 -45 46 38 50";
        String regex = " ";
        String[] split = s1.split(regex);
        int[] arr = new int[split.length];
        for (int i = 0; i < split.length; i++) {
    
    
            arr[i] = Integer.parseInt(split[i]);
        }
        Arrays.sort(arr);
        String s2 = "";
        for (int i = 0; i < arr.length; i++) {
    
    
            s2 = s2 + arr[i] + " ";
        }
        String s3 = s2.trim();
        System.out.println(s3);
    }
}

运行结果为：

3.按格式输出时间。

import java.text.SimpleDateFormat;
import java.util.Date;

public class DataTest {
    
    
    public static void main(String[] args) {
    
    
        Date date = new Date();
        SimpleDateFormat s1 = new SimpleDateFormat("yyyy-MM-dd HH-mm-ss E");
        String s2 = s1.format(date);
        System.out.println(s2);
    }
}

运行结果为：