java中判断字符串是否为纯数字

方法一：利用正则表达式

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public class Testone {

public static void main(String[] args){

String str="123456";

boolean result=str.matches("[0-9]+");

if (result == true) { 

System.out.println("该字符串是纯数字");

}else{

System.out.println("该字符串不是纯数字");

}

}

}

方法二：利用Pattern.

import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class Testone {

public static void main(String[] args){

String str="123456";

Pattern pattern = Pattern.compile("[0-9]{1,}");

Matcher matcher = pattern.matcher((CharSequence)str);

boolean result=matcher.matches();

if (result == true) {

System.out.println("该字符串是纯数字");

}else{

System.out.println("该字符串不是纯数字");

}

}

}