跨域解决

对于 CORS的跨域请求，主要有以下几种方式可供选择：

1.自定web filter 实现全局跨域

import org.springframework.context.annotation.Configuration;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebFilter(filterName = "CorsFilter ")
@Configuration
public class GlobalCorsConfig implements Filter {
    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        response.setHeader("Access-Control-Allow-Origin","*");
        response.setHeader("Access-Control-Allow-Credentials", "true");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, PATCH, DELETE, PUT");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
        chain.doFilter(req, res);
    }
}

　　

2.返回新的CorsFilter

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;

@Configuration
public class CrosConfig{
    @Bean
    public CorsFilter corsFilter() {
        //1. 创建CorsConfiguration对象
        CorsConfiguration corsConfiguration = new CorsConfiguration();
        corsConfiguration.addAllowedOrigin("*");//设置允许那些域来访问，*是通配符，允许所有域
        corsConfiguration.addAllowedHeader("*");//请求头字段
        corsConfiguration.addAllowedMethod("*");//请求方式(GET,POST,DELETE,PUT)
        //设置source
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", corsConfiguration);//1.映射路径 2.传入CorsConfiguration对象
        return new CorsFilter(source);

    }
}

3.重写 WebMvcConfigurer（待验证）

@Configuration
public class GlobalCorsConfig implements WebMvcConfigurer {
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                //是否发送Cookie
                .allowCredentials(true)
                //放行哪些原始域
                .allowedOrigins("*")
                .allowedMethods(new String[]{"GET", "POST", "PUT", "DELETE"})
                .allowedHeaders("*")
                .exposedHeaders("*");
    }
}

　　

4.使用注解 @CrossOrigin 局部跨域

在控制器(类上)上使用注解 @CrossOrigin:，表示该类的所有方法允许跨域。

import org.springframework.web.bind.annotation.CrossOrigin;

@RestController
@CrossOrigin(origins = "*")
public class HelloController {
    @RequestMapping("/hello")
    public String hello() {
        return "hello world";
    }
}

在方法上使用注解 @CrossOrigin:

import org.springframework.web.bind.annotation.CrossOrigin;

@RequestMapping("/hello")
    @CrossOrigin(origins = "*")
     //@CrossOrigin(value = "http://localhost:8081") //指定具体ip允许跨域
    public String hello() {
        return "hello world";
    }

　　

5.手动设置响应头 (HttpServletResponse)  局部跨域

@RequestMapping("/index")
public String index(HttpServletResponse response) {
    response.addHeader("Access-Allow-Control-Origin","*");
    return "index";
}