如何获取ajax的返回值

Question

jsp页面

js
$.ajax({
type:"post",
url:"randonu",
data:"randonu",
async:false,//是否异步
success:function(data){
alert(data);
}
});
action
private String num;
private boolean check;
if(num.equals("123")){
check=true;
}else{
check=false;
}
请问如何才能够获取到check的在jsp页面上进行判断是true还是false

Answer 1

action
PrintWriter out=response.getWriter();
out.print(check);
return null;
jsp
直接alert(data)