java正则匹配和替换非数字、非字母

Love The Way You Lie 2022-05-18 09:39 546阅读 0赞

使用java的正则匹配之前要记得导包

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

1.使用正则判断是否有数字、字母

public static void main(String[] args) {
            System.out.println(containsNum("111"));
            System.out.println(containsLetter("aaa"));
            System.out.println(containsNumOrLetter("aaa"));
        }
    //判断是否含有字母
        public static boolean containsLetter(String str) {
            String patt="[a-z|A-Z]";
            Pattern r = Pattern.compile(patt);
            Matcher matcher = r.matcher(str);
            return matcher.find();
        }
    //判断是否含有数字
        public static boolean containsNum(String str) {
            String patt="[0-9]";
            Pattern r = Pattern.compile(patt);
            Matcher matcher = r.matcher(str);
            return matcher.find();
        }
    //判断是否含有数字或字母
        public static boolean containsNumOrLetter(String str) {
            String patt="[0-9|a-z|A-Z]";
            Pattern r = Pattern.compile(patt);
            Matcher matcher = r.matcher(str);
            return matcher.find();
        }

2.那如果是判断是不含有字母或数字的正则怎么写呢？

public static void main(String[] args) {
            System.out.println(containsNoNum("111"));
            System.out.println(containsNoLetter("aaa"));
            System.out.println(containsNoNumOrLetter("aaa"));
        }
    
        public static boolean containsNoLetter(String str) {
            String patt="[^a-z]";
            Pattern r = Pattern.compile(patt);
            Matcher matcher = r.matcher(str);
            return matcher.find();
        }
    
        public static boolean containsNoNum(String str) {
            String patt="[^0-9]";
            Pattern r = Pattern.compile(patt);
            Matcher matcher = r.matcher(str);
            return matcher.find();
        }
    
        public static boolean containsNoNumOrLetter(String str) {
            String patt="[^0-9|a-z|A-Z]";
            Pattern r = Pattern.compile(patt);
            Matcher matcher = r.matcher(str);
            return matcher.find();
        }

3.根据上面的正则来写一个比较版本号的方法

public static void main(String[] args) {
            System.out.println(compareVersion("1.3_bc", "1.3_b"));
        }
    
    
        public static String compareVersion(String version1, String version2) {
    
            //忽略大小写，只保留数字和字母和点
            String v1 = version1.toLowerCase().replaceAll("[^0-9|a-z|.]", "");
            String v2 = version2.toLowerCase().replaceAll("[^0-9|a-z|.]", "");
            //按点来切割
            String[] arr1 = v1.split("\\.");
            String[] arr2 = v2.split("\\.");
            int len = arr1.length > arr2.length ? arr2.length : arr1.length;
    
            //正则判断是否含有字母
            String patt = "[a-z]";
            Pattern r = Pattern.compile(patt);
            int i = 0;
            do {
                Matcher m1 = r.matcher(arr1[i]);
                Matcher m2 = r.matcher(arr2[i]);
    
                boolean flag = false;
                //判断是否含有字母
                if (m1.find() && m2.find()) {//如果都含有字母
                    //先比较数字
                    String num1 = arr1[i].substring(0, m1.start());
                    String num2 = arr2[i].substring(0, m2.start());
                    if (Integer.parseInt(num1) > Integer.parseInt(num2)) {
                        return version1;
                    } else if (Integer.parseInt(num1) < Integer.parseInt(num2)) {
                        return version2;
                    }
                    //再比较含有字母的字符串
                    String str1 = arr1[i].substring(m1.start());
                    String str2 = arr2[i].substring(m2.start());
                    if (str1.compareTo(str2) > 0)
                        return version1;
                    else if (str1.compareTo(str2) < 0)
                        return version2;
                } else if ((flag = m1.find()) || m2.find()) {//如果只是其中一个含有字母
                    String vContains = flag ? arr1[i] : arr2[i];
                    String vOther = flag ? arr2[i] : arr1[i];
                    //先比较数字
                    String num1 = vContains.substring(0, flag ? m1.start() : m2.start());
                    String num2 = vOther;
                    if (Integer.parseInt(num1) > Integer.parseInt(num2)) {
                        return version1;
                    } else if (Integer.parseInt(num1) < Integer.parseInt(num2)) {
                        return version2;
                    }
                    return flag ? version1 : version2;
                } else {//如果都不含有字母，则直接比较数字
                    if (Integer.parseInt(arr1[i]) > Integer.parseInt(arr2[i])) {
                        return version1;
                    } else if (Integer.parseInt(arr1[i]) < Integer.parseInt(arr2[i])) {
                        return version2;
                    }
                }
            } while (++i < len);
    
            //以上判断都没有结果则返回数组 长度较长的那个版本
            return arr1.length > arr2.length ? version1 : version2;
        }

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