正则表达式、字符串生成器、随机数

package test;

import java.util.Random;

public class test {	
   
   public static void main(String[] args) {
		/*1.正则表达式
		 * String regex = "\\w+@\\w+(\\.\\w{2,3})*\\.\\w{2,3}"; String regex1 =
		 * "[^0]{1}\\d{10}"; String s ="[email protected]"; String s1 = "18535869370";
		 * if(s.matches(regex)) { System.out.println(s+"这是一个合法的邮箱号码"); }else {
		 * System.out.println(s+"这是一个非法邮箱"); } if(s1.matches(regex1)) {
		 * System.out.println(s1+"这是一个合法手机号"); }else {
		 * System.out.println(s1+"这是一个非法手机号"); }
		 */
		/*2.字符串生成器
		 * String str=""; StringBuilder builder= new StringBuilder("");//创建字符串生成器 long
		 * starTime = System.currentTimeMillis(); for(int i=0;i<100000;i++) {
		 * builder.append(i); //循环追加字符 } long endTime =System.currentTimeMillis(); long
		 * time = endTime-starTime; System.out.println("消耗了多少"+time); StringBuilder bu=
		 * new StringBuilder("hello"); bu.insert(5, "world");
		 * System.err.println(bu.toString()); StringBuilder bu1= new
		 * StringBuilder("helloworld"); bu1.delete(3, 4);
		 * System.out.println(bu1.toString());
		 */
		/*3.一维数组和二维数组的使用
		 * String year[] = new String[]{"春","夏","秋","冬"}; for(int i=0; i<4;i++) {
		 * System.out.println("第"+(i+1)+"季"+year[i]+"天"); }
		 * int arr[][] = new int[][] {{2},{3,3},{4,4,4}}; for(int i=0;iarray[j+1]) { int t=array[j]; array[j]=array[j+1]; array[j+1]=t;
		 * } } } showArray(array); } public void showArray(int[]array) { for (int
		 * i=0;i>"+array[i]); }
		 * System.out.println();
		 */
		/*5.对象的比较
		 * String c1 = new String("abc"); String c2 = new String("abc"); String c3 = c1;
		 * System.out.println("第一个结果"+(c2==c3));//==比较两个对象的引用地址是否相等
		 * System.out.println("第二个结果"+(c2.equals(c3)));//equal比较两个对象的引用内容是否相等
		 */		
	    /*6.随机数的生成
	     *  System.out.println("任意小写字符"+GetRandomChar('a', 'z'));
	        System.out.println("任意大写字符"+GetRandomChar('A', 'Z'));
	        System.out.println("0到9的任意字符"+GetRandomChar('0', '9'));}
            public static char  GetRandomChar(char char1,char char2) {
		    return (char)(char1+Math.random()*(char2-char1+1));	}	
	     */
	    }
}