2023-03-03 java 判斷字元是否都是數字組成、或者數字和某個字元組成

一、判斷字元是否都是數字代碼

public static boolean isNumer(String str){ 
        Pattern pattern = Pattern.compile("[0-9]*"); 
        Matcher isNum = pattern.matcher(str);
        if( !isNum.matches() ){
           return false; 
         } 
        return true; 
    }
           

二、判斷字元是否都是數字或者某個字元（下面是.）組成代碼

public static boolean isNumer_char(String str){ 
        Pattern pattern = Pattern.compile("[0-9.]*"); 
        Matcher isNum = pattern.matcher(str);
        if( !isNum.matches() ){
           return false; 
         } 
        return true; 
    }
           

三、判斷字元是否都是數字或者某幾個字元（下面是.lt）組成代碼

public static boolean isNumer_nchar(String str){ 
        Pattern pattern = Pattern.compile("[0-9.lt]*"); 
        Matcher isNum = pattern.matcher(str);
        if( !isNum.matches() ){
           return false; 
         } 
        return true; 
    }
           

四、測試java代碼，運作結果

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    
    public static boolean isNumer(String str){ 
        Pattern pattern = Pattern.compile("[0-9]*"); 
        Matcher isNum = pattern.matcher(str);
        if( !isNum.matches() ){
           return false; 
         } 
        return true; 
    }
    public static boolean isNumer_char(String str){ 
        Pattern pattern = Pattern.compile("[0-9.]*"); 
        Matcher isNum = pattern.matcher(str);
        if( !isNum.matches() ){
           return false; 
         } 
        return true; 
    }
    
    public static boolean isNumer_nchar(String str){ 
        Pattern pattern = Pattern.compile("[0-9.lt]*"); 
        Matcher isNum = pattern.matcher(str);
        if( !isNum.matches() ){
           return false; 
         } 
        return true; 
    }

	public static void main(String[] args) {
	    String i = "01229";
	    String j = "12523";
	  	String m = "12j23";  
	  	String n = "12.23";  
	  	String r = "12..23"; 
	  	String p = "12n23"; 
	  	String t = "12lt23"; 
	  	
	  	System.out.println("************isNumer************");
	    System.out.println(i+" isNumer:"+isNumer(i));
	    System.out.println(j+" isNumer:"+isNumer(j));
        System.out.println(m+" isNumer:"+isNumer(m));
        System.out.println(n+" isNumer:"+isNumer(n));
        
  	  	System.out.println("************isNumer_char************");    
  	  	System.out.println(i+" isNumer_char:"+isNumer_char(i));
        System.out.println(n+" isNumer_char:"+isNumer_char(n));
        System.out.println(p+" isNumer_char:"+isNumer_char(p));
        System.out.println(r+" isNumer_char:"+isNumer_char(r));
        
  	  	System.out.println("************isNumer_nchar************");    
         System.out.println(t+" isNumer_char:"+isNumer_char(t));
         System.out.println(t+" isNumer_nchar:"+isNumer_nchar(t));
        
		System.out.println("Hello, World");
	}
}
           

************isNumer************
01229 isNumer:true
12523 isNumer:true
12j23 isNumer:false
12.23 isNumer:false
************isNumer_char************
01229 isNumer_char:true
12.23 isNumer_char:true
12n23 isNumer_char:false
12..23 isNumer_char:true
************isNumer_nchar************
12lt23 isNumer_char:false
12lt23 isNumer_nchar:true
Hello, World
           

五、參考文章

Android正規表達式及Pattern Matcher使用 #Android #Pattern - 簡書

android：java 判斷字元串是否全是數字_android 判斷純數字_龍騰騰的部落格-CSDN部落格