Scanner sc=new Scanner(System.in);
System.out.println("请输入行数和列数");
int x=sc.nextInt();
int y=sc.nextInt();
for(int i=0;i<y;i++) {
for(int j=0;j<x;j++) {
if(i ==0) {
System.out.print("*");
}
else if(i == y -1) {
System.out.print("*");
}
else if(j == 0 || j == y-1) {
System.out.print("*");
}
else {
System.out.print("");
}
}
System.out.println();
}
}
}