Spring Boot如何解决has been blocked by CORS policy跨域问题呢?

我们的项目是前后端分离的项目
   今天前端访问后端时，竟然遇到了跨域问题
   返回的代码如下所示:
     ...... has been blocked by CORS policy: No ‘Access-Control-Allow-Origin‘ ......  

 我们只需在相应的Controller上面加上@CrossOrigin注解,即可处理CORS跨域问题
   
import com.cn.springboothelloworldinitializr.entity.User;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.Arraylist;
import java.util.List;
 
@RestController
@RequestMapping("/test")
// 解决跨域
@CrossOrigin
public class Controller {

    @RequestMapping("/test1")
    public void test1(){
        System.out.println("Hello java265.com");
    }
}