JAVA中正则表达式处理字符串的四个常用方法：匹配、分割、替换、截取。其跟字符串的常用函数相似，但是使用正则表达式会更简单、更加简洁。下面是具体的例子：
public class TestRegex {
public static void main(String[] args) {
String str = "";
String regex = "";
// 匹配
regex = "[1-9][a-z]";
getMatches(str, regex);
// 分割
str = "1a<a>:abc123:</a>";
regex = ":";
getSpilt(str, regex);
// 替换
str = "1223334444aaabbc";
String oldChar = "(.)\\1+";
regex = "$1";
getReplace(str, oldChar, regex);
// 截取
str = "<title>test string</title><a>url</a><content>abc123</content>";
regex = "<a>(.*)</a>";
getSubstring(str, regex);
}
public static void getMatches(String str, String regex) {
System.out.println(str.matches(regex));
}
public static void getSpilt(String str, String regex) {
String[] array = str.split(regex);
for (String t : array) {
System.out.println(t);
}
}
public static void getReplace(String str, String oldChar, String regex) {
System.out.println(str.replaceAll(oldChar, regex));
}
public static void getSubstring(String str, String regex) {
Pattern p = Pattern.compile(regex);
Matcher m = p.matcher(str);
if (m.find()) {
System.out.println(m.group(1));
}
}
}