has been blocked by CORS policy: Response to preflight request doesn't pass access control check: The value of the 'Access-Control-Allow-Credentials' header in the response is '' which must be 'true' when the request's credentials mode is 'include'. The credentials mode of requests initiated by the XMLHttpRequest is controlled by the withCredentials attribute.Java应该用代码怎么解决
时间: 2023-11-27 12:53:19 浏览: 285
这个问题是由于浏览器的跨域安全策略导致的,可以通过在服务端设置CORS头来解决。在Java中,可以通过使用Spring框架的CorsFilter来实现。
以下是一个示例代码:
```java
import org.springframework.web.filter.CorsFilter;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import javax.servlet.FilterRegistration;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
public class MyWebApplicationInitializer implements WebApplicationInitializer {
@Override
public void onStartup(ServletContext servletContext) throws ServletException {
// 创建CorsConfiguration对象
CorsConfiguration config = new CorsConfiguration();
// 设置允许跨域的源
config.addAllowedOrigin("*");
// 设置允许跨域的方法
config.addAllowedMethod("*");
// 设置允许跨域的Header
config.addAllowedHeader("*");
// 设置是否支持凭证(如cookie)
config.setAllowCredentials(true);
// 创建UrlBasedCorsConfigurationSource对象,并注册CorsConfiguration
UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
source.registerCorsConfiguration("/**", config);
// 创建CorsFilter对象,并将其添加到FilterRegistration中
CorsFilter corsFilter = new CorsFilter(source);
FilterRegistration.Dynamic registration = servletContext.addFilter("corsFilter", corsFilter);
registration.addMappingForUrlPatterns(null, false, "/*");
}
}
```
上面的代码使用了Spring框架的CorsFilter来处理跨域请求,将其添加到了过滤器链中。其中,设置了允许跨域的源、方法、Header以及是否支持凭证等相关配置,以解决CORS相关的问题。