Regular expression matching, replacement, search, and cutting methods in JAVA
正则表达式的查找;主要是用到String类中的split();
String str;
str.split();方法中传入按照什么规则截取,返回一个String数组
常见的截取规则:
str.split("\\.")按照.来截取
str.split(" ")按照空格截取
str.split("cc+")按照c字符来截取,2个c或以上
str.split((1)\\.+)按照字符串中含有2个字符或以上的地方截取(1)表示分组为1
截取的例子;
按照分组截取;截取的位置在两个或两个以上的地方
String str = "publicstaticccvoidddmain";
//对表达式进分组重用
String ragex1="(.)\\1+";
String[] ss = str.split(ragex1);
for(String st:ss){
System.out.println(st);
}
//按照两个cc+来截取
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("=-=========");
正则表达式中的替换;
语法定义规则;
String s =str.replaceAll(ragex, newstr);
字符串中的替换是replace();
将4个或4个以上的连续的数字替换成*
// 替换
String str="wei232123jin234";
String ragex = "\\d{4,}";
String newstr = "*";
String s =str.replaceAll(ragex, newstr);
System.out.println(s);将重复的字符串换成一个*
String str ="wwweiei222222jjjiiinnn1232"; String ragex ="(.)\\1+"; String newStr ="*"; String s = str.replaceAll(ragex, newStr); System.out.println(s);
将 我...我...要..要.吃...吃...饭 换成 我要吃饭
String str = "我...我...要..要.吃...吃...饭";
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;
}
正则表达式的字符串的获取
1,根据定义的正则表达式创建Pattern对象
2,使用Pattern对象类匹配
3,判断是否为true
4,加入到组
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);
}
作业:
1,获取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,获取dhfjksaduirfn 11@qq.com dsjhkfa wang@163.com wokaz中的邮箱号码
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());
}
}
示例代码：
import java.util.ArrayList;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class test {
public static void main(String[] args) {
getStrings(); //用正则表达式获取指定字符串内容中的指定内容
System.out.println("********************");
replace(); //用正则表达式替换字符串内容
System.out.println("********************");
strSplit(); //使用正则表达式切割字符串
System.out.println("********************");
strMatch(); //字符串匹配
}
private static void strMatch() {
String phone = "13539770000";
//检查phone是否是合格的手机号(标准:1开头，第二位为3,5,8，后9位为任意数字)
System.out.println(phone + ":" + phone.matches("1[358][0-9]{9,9}")); //true
String str = "abcd12345efghijklmn";
//检查str中间是否包含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";
//将字符串中的.替换成_，因为.是特殊字符，所以要用\.表达，又因为\是特殊字符，所以要用\\.来表达.
str = str.replaceAll("\\.", "_");
System.out.println(str);
}
}更多JAVA中正则表达式匹配，替换，查找，切割的方法相关文章请关注PHP中文网！
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