public class KongGe {
public static void main(String[] args) {
//我们知道String有3个用于字符替换的方法,分别是:
//String replace(CharSequence target, CharSequence replacement):将字符串中出现的target替换成replacement;
//String replaceAll(String regex, String replacement):regex是一个正则表达式,将字符串中匹配的子字符串替换为replacement;
//String replaceFirst(String regex, String replacement):和replaceAll(..)类似,只不过只替换第一个出现的地方。
String input = "abcdefghijklmnopqrsta";
//正则表达式中任意字符出现两次
String regex = "(.{2})";
String tegex1 ="a";
System.out.println(input.replaceAll(regex, "$1 "));
System.out.println(input.replace(tegex1,"c"));
System.out.println(input.replaceFirst(tegex1, "8"));
}
}
打印结果:
ab cd ef gh ij kl mn op qr st a
cbcdefghijklmnopqrstc8bcdefghijklmnopqrsta