java判断是否数字

和一些零碎的东西

package cn;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.HashMap;

import java.util.Map;

import java.util.Random;

public class Test {

public static void main(String[] args) {

/*String str = ",";

String strSub = str.substring(1, str.length());*/

//System.out.println(str.substring(1, str.length()));

/*Map map = new HashMap();

map.put("123hjy", "haahha");

System.out.println(map.get("123hjy"));*/

//System.out.println(isDouble("4523.552"));//isDouble isInteger

/*String strs = "abc";

String[] hao = strs.split(",");

for(int i=0;i<hao.length;i++){

System.out.println(hao[i] + "@");

}*/

/*double num = 25.;

//System.out.println(isDouble("25."));

SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMdd");

System.out.println(dateFormat.format(new Date()));

System.out.println(new Random().nextInt(99));

int n = 1;

for(int i=0;i<n;i++){

System.out.println("hao");

if(n==1){

n++;

}

}*/

/*Date now = new Date();

System.out.println(now.getDay());

now.setDate(now.getDate()+650);

SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");

System.out.println(format.format(now));*/

/*String str = "00474";

System.out.println(str.length());

System.out.println(Integer.parseInt(str));

SimpleDateFormat dateFormat = new SimpleDateFormat("yyMMdd");

System.out.println(dateFormat.format(new Date()));*/

/*String str = "100041208160159";

int hao = Integer.parseInt(str.substring(11, 15));

System.out.println(hao);

System.out.println(str.substring(11, 15));*/

String you = "";

System.out.println(you.trim());

}

/**

* 判断是否是数字类型

* @param str

* @return

*/

public static boolean isInteger(String str){

boolean flag = true;

for(int i=0;i<str.length();i++){

if (!Character.isDigit(str.charAt(i))){

flag = false;

break;

}

}

return flag;

}

/**

* 判断是否是数字类型

* @param str

* @return

*/

public static boolean isDouble(String str){

try

{

Double.parseDouble(str);

return true;

}catch(Exception ex){

return false;

}

}

}