char temp[N];
int res=0, len=0;
for(int i=0;i<strlen;i++)
{
    char c=s.charAt;
    if(c>='0'&&c<='9')
         temp[len++]=c-'0';
}
temp[len]='\0';
//res=Integer.valueOf(temp);
   res=Integer.getInteger(temp);这两个函数都可以用的

import java.util.regex.*; 
public class Test{
  public static void main(String[] args){
    String s = "ad8fas9d12342d2s";
     Pattern p=Pattern.compile("\\d+"); 
     Matcher m=p.matcher;
     String sb=new String();
     while(m.find()) {sb=sb+m.group();}
      System.out.print(sb);
    }
}

import java.util.regex.*; 
public class Test{
  public static void main(String[] args){
    String s = "ad8fas9d12342d2s";
    Pattern p=Pattern.compile("\\d+"); 
    Matcher m=p.matcher;
    StringBuffer sb=new StringBuffer();
    while(m.find()) {
      sb.append(m.group());
    }
    System.out.print(sb);
  }
}

gongshi wrote:
To xunloveru
Your code is good, but my suggestion is using StringBuffer instead of String in this case.

ww1ww1 wrote:
Maybe StringBuilder is better.

why wrote:
StringBuilder is good, but it is only available in Java 5.0