CORS Angular和SpringBoot-请求被阻止

Question

我有一个似乎无法解决的问题。我想从我的网站发送http请求

角客户端：

const url = 'http://localhost:8080/api';
console.log(this.http.get(url).subscribe(data => this.greeting = data));

到我使用CORS注释的SpringBoot后端：

@CrossOrigin(origins = "http://localhost:4200/", maxAge = 3600)
    @RequestMapping("/api/")
    public Map<String,Object> home() {
        Map<String,Object> model = new HashMap<String,Object>();
        model.put("id", UUID.randomUUID().toString());
        model.put("content", "Hello World");
        return model;
    }

但我收到一个错误，该错误已被阻止，并始终将我重定向到登录名。

Failed to load http://localhost:8080/api: Redirect from 'http://localhost:8080/api' to 'http://localhost:8080/login' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:4200' is therefore not allowed access. 

有办法改变吗？

我对此表示感谢或帮助。我想了解为什么会发生此问题。

Answer 1

RequestMapping如您所用@RequestMapping("/api/")，您的错误将被评估为http://your_url/api//。这样的映射在您的控制器中不存在，因此它给您带来CORS Origin错误。

只是删除尾随/从@RequestMapping("/api/")这样，这将是@RequestMapping("/api")。

您的课程应如下所示，

@RestController
@CrossOrigin(origins = "http://localhost:4200")
public class DemoController {

    @RequestMapping(value = "/api", method = RequestMethod.GET)
    public Map<String,Object> home() {
        Map<String,Object> model = new HashMap<String,Object>();
        model.put("id", UUID.randomUUID().toString());
        model.put("content", "Hello World");
        return model;
    }
}

Answer 2

这是你的服务器端的问题。您所要做的就是在服务器端执行一个组件，它将解决问题。或参考这里

请遵循以下代码：

@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class RequestFilter implements Filter {

    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) {
        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;

        response.setHeader("Access-Control-Allow-Origin", "http://localhost:4200");
        response.setHeader("Access-Control-Allow-Methods", "POST, PUT, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Credentials", "true");

        if (!(request.getMethod().equalsIgnoreCase("OPTIONS"))) {
            try {
                chain.doFilter(req, res);
            } catch(Exception e) {
                e.printStackTrace();
            }
        } else {
            System.out.println("Pre-flight");
            response.setHeader("Access-Control-Allow-Methods", "POST,GET,DELETE");
            response.setHeader("Access-Control-Max-Age", "3600");
            response.setHeader("Access-Control-Allow-Headers", "authorization, content-type," +
                    "access-control-request-headers,access-control-request-method,accept,origin,authorization,x-requested-with");
            response.setStatus(HttpServletResponse.SC_OK);
        }

    }
    }