反向引用
- 表示匹配连续两个相同的数字:(\d)\1
- 匹配五个连续的相同数字:(\d)\1{4}等价于\d\1\1\1\1
- 匹配个位与千位相同,十位与百位相同的数(\d)(\d)\2\1
public class RegExp13 {
public static void main(String[] args){
//String content = "hello22222 jack1991 tom179971 jack22 yyy xxx";
//匹配两个相同的数
//String regStr = "(\\d)\\1";
//匹配五个连续的相同数字
//String regStr = "(\\d)\\1{4}";
//匹配个位与千位相同,十位与百位相同
//String regStr = "(\\d)(\\d)\\2\\1";
/**
* 请在字符串中检索商品编号,形式如:12321-333999111 这样的号码
* 要求满足前面是一个五位数,然后一个“-”号,的9位数,连续的每三位要相同
*/
String content ="r12321-333999111r";
String regStr ="\\d{5}-(\\d)\\1{2}(\\d)\\2{2}(\\d)\\3{2}";
Pattern pattern = Pattern.compile(regStr);
Matcher matcher = pattern.matcher(content);
while(matcher.find()){
System.out.println("找到:"+matcher.group(0));
}
}
}
- 我…我要…学学学学…编程java! 替换成 我要学编程java!
public class RegExp14 {
public static void main(String[] args){
String content ="我...我要....学学学学....编程java!";
String regStr ="\\.";
Pattern pattern = Pattern.compile(regStr);
Matcher matcher = pattern.matcher(content);
//1.先替换.为空字符
content = matcher.replaceAll("");
System.out.println("替换后的值:"+content);
//2.反向引用将重复的值过滤掉
// (1)使用(.)\\1+
// (2) 使用反向引用$1来替换匹配到的内容
Pattern pattern1 = Pattern.compile("(.)\\1+");
Matcher matcher1 = pattern1.matcher(content);
while (matcher1.find()){
System.out.println("找到:"+matcher1.group(0));
}
//使用反向引用$1来替换匹配到的内容
content = matcher1.replaceAll("$1");
System.out.println("替换后:"+content);
content = Pattern.compile("(.)\\1+").matcher(content).replaceAll("$1");
System.out.println("链式替换后:"+content);
}
}