站長(zhǎng)資訊網(wǎng)正則表達(dá)式的查找;主要是用到String類中的split();
String str;
str.split();方法中傳入按照什么規(guī)則截取,返回一個(gè)String數(shù)組
常見(jiàn)的截取規(guī)則:
str.split(“\.”)按照.來(lái)截取
str.split(” “)按照空格截取
str.split(“cc+”)按照c字符來(lái)截取,2個(gè)c或以上
str.split((1)\.+)按照字符串中含有2個(gè)字符或以上的地方截取(1)表示分組為1
截取的例子;
按照分組截取;截取的位置在兩個(gè)或兩個(gè)以上的地方
String str = "publicstaticccvoidddmain"; //對(duì)表達(dá)式進(jìn)分組重用 String ragex1="(.)\1+"; String[] ss = str.split(ragex1); for(String st:ss){ System.out.println(st); } //按照兩個(gè)cc+來(lái)截取 String ragex = " "; //切割 String strs = "publicstaticccvoidddmain"; String ragexs = "cc+"; String[] s = strs.split(ragexs); for(String SSSS :s){ System.out.println(SSSS); } System.out.println("=-=========");
正則表達(dá)式中的替換;
語(yǔ)法定義規(guī)則;
String s =str.replaceAll(ragex, newstr);
字符串中的替換是replace();
將4個(gè)或4個(gè)以上的連續(xù)的數(shù)字替換成*
// 替換 String str="wei232123jin234"; String ragex = "\d{4,}"; String newstr = "*"; String s =str.replaceAll(ragex, newstr); System.out.println(s);
將重復(fù)的字符串換成一個(gè)*
String str ="wwweiei222222jjjiiinnn1232"; String ragex ="(.)\1+"; String newStr ="*"; String s = str.replaceAll(ragex, newStr); System.out.println(s);
將 我…我…要..要.吃…吃…飯 換成 我要吃飯
String str = "我...我...要..要.吃...吃...飯"; String regex = "\.+"; String newStr = ""; str=test(str, regex, newStr); regex = "(.)\1+"; newStr = "$1"; test(str, regex, newStr); public static String test(String str, String regex, String newStr) { String str2 = str.replaceAll(regex, newStr); System.out.println(str2); return str2; }
正則表達(dá)式的字符串的獲取
1,根據(jù)定義的正則表達(dá)式創(chuàng)建Pattern對(duì)象
2,使用Pattern對(duì)象類匹配
3,判斷是否為true
4,加入到組
例子;
String str = "public static void main(String[] args)" + " public static void main(String[] args)public static void main(String[] args)"; String ragex = "\b[a-zA-Z]{4,5}\b"; Pattern p =Pattern.compile(ragex); Matcher m = p.matcher(str); while(m.find()){ String s = m.group(); System.out.println(s); }
作業(yè):
1,獲取<html>user</user>中的user
String str ="<html>user</html>"; String regex = "<html>|</html>"; String newStr = ""; String str2 = str.replaceAll(regex, newStr); System.out.println(str2);
2,獲取dhfjksaduirfn 11@qq.com dsjhkfa wang@163.com wokaz中的郵箱號(hào)碼
String regex = " "; String[] strs=str.split(regex); for(String str2:strs){ String ragexDemo = "[a-zA-Z0-9]([a-zA-Z0-9]*[-_]?[a-zA-Z0-9]+)*" + "@([a-zA-Z0-9]+)\.[a-zA-Z]+\.?[a-zA-Z]{0,2}"; Pattern p = Pattern.compile(ragexDemo); Matcher m = p.matcher(str2); while(m.find()){ System.out.println(m.group()); } }
示例代碼：
import java.util.ArrayList; import java.util.regex.Matcher; import java.util.regex.Pattern; public class test { public static void main(String[] args) { getStrings(); //用正則表達(dá)式獲取指定字符串內(nèi)容中的指定內(nèi)容 System.out.println("********************"); replace(); //用正則表達(dá)式替換字符串內(nèi)容 System.out.println("********************"); strSplit(); //使用正則表達(dá)式切割字符串 System.out.println("********************"); strMatch(); //字符串匹配 } private static void strMatch() { String phone = "13539770000"; //檢查phone是否是合格的手機(jī)號(hào)(標(biāo)準(zhǔn):1開(kāi)頭，第二位為3,5,8，后9位為任意數(shù)字) System.out.println(phone + ":" + phone.matches("1[358][0-9]{9,9}")); //true String str = "abcd12345efghijklmn"; //檢查str中間是否包含12345 System.out.println(str + ":" + str.matches("\w+12345\w+")); //true System.out.println(str + ":" + str.matches("\w+123456\w+")); //false } private static void strSplit() { String str = "asfasf.sdfsaf.sdfsdfas.asdfasfdasfd.wrqwrwqer.asfsafasf.safgfdgdsg"; String[] strs = str.split("\."); for (String s : strs){ System.out.println(s); } } private static void getStrings() { String str = "rrwerqq84461376qqasfdasdfrrwerqq84461377qqasfdasdaa654645aafrrwerqq84461378qqasfdaa654646aaasdfrrwerqq84461379qqasfdasdfrrwerqq84461376qqasfdasdf"; Pattern p = Pattern.compile("qq(.*?)qq"); Matcher m = p.matcher(str); ArrayList<String> strs = new ArrayList<String>(); while (m.find()) { strs.add(m.group(1)); } for (String s : strs){ System.out.println(s); } } private static void replace() { String str = "asfas5fsaf5s4fs6af.sdaf.asf.wqre.qwr.fdsf.asf.asf.asf"; //將字符串中的.替換成_，因?yàn)?是特殊字符，所以要用.表達(dá)，又因?yàn)槭翘厥庾址砸肻.來(lái)表達(dá). str = str.replaceAll("\.", "_"); System.out.println(str); } }
