正则表达式&自定义异常 典型案例
发布时间:2020-12-14 01:41:44 所属栏目:百科 来源:网络整理
导读:import java.util.regex.Matcher;import java.util.regex.Pattern;public class Test{public static void main(String[] args){System.out.println(oper(" 12.3+213.1"));}public static float oper(String s){Float res = null;Pattern p = Pattern.compile
import java.util.regex.Matcher; import java.util.regex.Pattern; public class Test { public static void main(String[] args) { System.out.println(oper(" 12.3+213.1")); } public static float oper(String s) { Float res = null; Pattern p = Pattern .compile("s*(d+)(.*)(d+)s*(+|-|*/)s*(d+)(.*)(d+)s*"); Matcher m = p.matcher(s); boolean b = m.matches(); if (!b) { throw new couldNotCaculateException("匹配错误"); } String s1 = m.group(1) + m.group(2) + m.group(3); String s2 = m.group(5) + m.group(6) + m.group(7); Float f1 = Float.parseFloat(s1); Float f2 = Float.parseFloat(s2); if ("+".equals(m.group(4))) { res = f1 + f2; } else if ("-".equals(m.group(4))) { res = f1 - f2; } else if ("*".equals(m.group(4))) { res = f1 * f2; } else if ("/".equals(m.group(4))) { if (f2 == 0) { throw new couldNotCaculateException("除数不能为o"); } res = f1 / f2; } return res; } } class couldNotCaculateException extends RuntimeException { private static final long serialVersionUID = -1127307315212919888L; public couldNotCaculateException(String msg) { super(msg); } } (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |