引入包：import java.util.Scanner;

main函式：

public static void main(String[] args){
Scanner s = new Scanner(System.in);
System.out.println("請輸入字串");
String strIn= s.nextLine();
System.out.println("請輸入子串");
String strCh = s.nextLine();

boolean isCon=true; //判斷是否存在字串
if(!strIn.contains(strCh)){
isCon=false;
}
if(isCon){//如果存在
System.out.print("包含該字串,");
int preStrLength = 0;
System.out.print("且查詢到該子串的位置為：");
        while(true){
                        int pos = strIn.indexOf(strCh);
                if(pos==-1)break;
System.out.print((pos + preStrLength));//字串位置
System.out.print(' ');
strIn= strIn.substring(pos +strCh.length()  );//擷取
preStrLength +=(pos +strCh.length());
                }
}else{
System.out.println("不包含該字串");
}
}