在一个字符串中查找是否包含某个字符串,并计算出包含的个数

public class ContainsTest {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.println("请输入一个字符串");
String str = in.next();
String s = str;
System.out.println("请输入要查找的字符串");
String tr = in.next();
int count = 0;
for(int i = 0; i<str.length(); i++){
int c = -1;
c = str.indexOf(tr);
if(c != -1){
str = str.substring(c+1);
count++;
}
}
System.out.println(s+"中包含"+count+"个"+tr);
}

}