这是一个返回所有区域对象的控制器
已从CORS策略阻止从原点[http://localhost:8080/'访问'http://localhost:3000处XMLHttpRequest:在所请求的资源上没有'Access-Control-Allow-Origin'标头。
package com.ministry.demo.controller;
import com.ministry.demo.model.District;
import com.ministry.demo.repository.DistrictRepository;
import com.ministry.demo.service.DistrictService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
@RequestMapping(path = "district")
public class DistrictController {
@Autowired
DistrictService service;
@GetMapping(path = "getAll")
List<District> getAllDistrict(){
return service.getAllDistricts();
}
}
如果后端和应用程序不在同一地址上运行,则浏览器通常不允许您调用后端。这旨在成为一项安全功能。
要允许浏览器调用api,请在后端响应中添加Access-Control-****标头(从Spring答复时)。
请参见https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Origin
允许所有来源的最基本的标头:
Access-Control-Allow-Origin: *
这里是在Spring中添加这些标题的教程:https://spring.io/guides/gs/rest-service-cors/
MyConfiguration.java
@Configuration
public class MyConfiguration implements WebMvcConfigurer {
@Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/**")
.allowedMethods("*");
}
}