求两字符串最大公共子串

//思路:遍历小字符串的每一个子串,然后跟大的字符串比较是否包含
public class TestDemo04 {

/**
* @param args
*/
public static void main(String[] args) {
String s1 = "aaaaaaitcaastbbb";
String s2 = "cccdddeeefffgggitcasthhhiiiaa";
String tmp = "";
for (int i = 0; i < s1.length(); i++) {
for (int j = s1.length()-i; j >i; j--) {
String tmp1 = s1.substring(i, j);
if (s2.contains(tmp1) && (tmp1.length() > tmp.length())) {
tmp = tmp1;
break;

}

}

}
System.out.println(tmp);
}

}