java：判断字符串是否为数字

java：判断字符串是否为数字

1 简单封装，兼容负数情况（不含小数点）

package com.xiaoxu.utils.str;

import org.springframework.util.StringUtils;

/**
 * @author xiaoxu
 * @date 2022-08-03
 * spring_boot:com.xiaoxu.utils.str.StrUtil
 */
public class StrUtil {
    /*
    * 判断字符串是否为数字(不能含小数点)
    * */
    public static boolean isNumeric(String str){
        if(!StringUtils.hasLength(str)){
            return false;
        }
        CharSequence cs = str;
        if(cs.charAt(0)=='-'&&StringUtils.countOccurrencesOf(str,"-")==1){
            cs = str.substring(1);
        }
        for(int var1 = 0;var1<cs.length();++var1){
            char c = cs.charAt(var1);
            if(!Character.isDigit(c)){
                return false;
            }
        }
        try {
            Long.parseLong(cs.toString());
        } catch (NumberFormatException e) {
            return false;
        }
        return true;
    }

    public static void main(String[] args) {
        System.out.println(isNumeric("-1 "));
        System.out.println(isNumeric(" -1"));
        System.out.println(isNumeric("-1"));
        System.out.println(isNumeric("a1212"));
        System.out.println(isNumeric("1213"));
        System.out.println(isNumeric("000071213"));
        System.out.println(isNumeric("-00007100213"));
        System.out.println(isNumeric("--00007100213"));
        System.out.println(isNumeric("-00007100213小徐"));
        System.out.println(isNumeric("-00007100213.0"));
        System.out.println(isNumeric("00"));
        System.out.println(isNumeric("-00"));
        System.out.println(isNumeric("0"));
        System.out.println(isNumeric("-0"));
        System.out.println(isNumeric("-"));
        System.out.println(isNumeric("- "));
    }
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54

2 执行结果

false
false
true
false
true
true
true
false
false
false
true
true
true
true
false
false
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16