SpringBoot 项目之前端跨域终结者

左手的ㄟ右手 2022-01-28 09:59 155阅读 0赞

### 文章目录 ###

*   *   *  1 摘要
         *  2 核心代码
         *  3 参考资料推荐
         *  4 Github 源码

### 1 摘要 ###

跨域一直是一个令人头疼的问题，对于初学者而言可能觉得本地测试接口都没有问题，为什么部署到线上就出现bug了，完全没有头脑。对于前端 VUE 开发者而言，后台不处理，基本就会出现跨域问题。而处理跨域问题的方案也是八仙过海，各显神通。本文将介绍在 Spring Boot 项目中一种相对传统的方法，通过拦截器的方式彻底解决跨域问题。

(PS: 在文末参考资料中也有使用 Spring 框架自带的跨域问题解决方案)

### 2 核心代码 ###

../demo-web/src/main/java/com/ljq/demo/springboot/web/acpect/SimpleCORSFilter.java

package com.ljq.demo.springboot.web.acpect;
    
    import javax.servlet.*;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    /** * @Description: 跨域请求拦截器(简易版) * @Author: junqiang.lu * @Date: 2019/5/21 */
    public class SimpleCORSFilter implements Filter { 
        @Override
        public void init(FilterConfig filterConfig) throws ServletException { 
    
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { 
            HttpServletRequest httpRequest = (HttpServletRequest) servletRequest;
            HttpServletResponse httpResponse = (HttpServletResponse) servletResponse;
            // *表示允许所有域名跨域
            httpResponse.addHeader("Access-Control-Allow-Origin", "*");
            httpResponse.addHeader("Access-Control-Allow-Headers",
                    "Origin, X-Requested-With, Content-Type, Accept");
            // 允许跨域的Http方法
            httpResponse.addHeader("Access-Control-Allow-Methods", "GET,HEAD,POST,PUT,PATCH,DELETE,OPTIONS,TRACE");
            // 应对探针模式请求(OPTIONS)
            String methodOptions = "OPTIONS";
            if (httpRequest.getMethod().equals(methodOptions)) { 
                httpResponse.setStatus(HttpServletResponse.SC_ACCEPTED);
                return;
            }
    
            filterChain.doFilter(httpRequest, servletResponse);
        }
    
        @Override
        public void destroy() { 
    
        }
    }

SpringBoot 启动类

../demo-web/src/main/java/com/ljq/demo/springboot/web/DemoWebApplication.java

package com.ljq.demo.springboot.web;
    
    import com.ljq.demo.springboot.web.acpect.SimpleCORSFilter;
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.builder.SpringApplicationBuilder;
    import org.springframework.boot.web.servlet.ServletComponentScan;
    import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
    import org.springframework.cache.annotation.EnableCaching;
    import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.ComponentScan;
    
    @SpringBootApplication
    @EnableEurekaServer
    @ComponentScan(basePackages = { "com.ljq.demo"})
    @MapperScan("com.ljq.demo.springboot.dao")
    @ServletComponentScan
    @EnableCaching
    public class DemoWebApplication extends SpringBootServletInitializer { 
    
        public static void main(String[] args) { 
            SpringApplication.run(DemoWebApplication.class, args);
        }
    
        @Override
        protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) { 
            return builder.sources(DemoWebApplication.class);
        }
    
        /** * 跨域处理 * * @return */
        @Bean
        public SimpleCORSFilter simpleCORSFilter(){ 
            return new SimpleCORSFilter();
        }
    }

### 3 参考资料推荐 ###

[Java CORS Filter Example][]

[Spring CORS – Spring @CrossOrigin example][Spring CORS _ Spring _CrossOrigin example]

[CORS with Spring][]

### 4 Github 源码 ###

**Gtihub 源码地址** : [https://github.com/Flying9001/springBootDemo][https_github.com_Flying9001_springBootDemo]

个人公众号:**404Code**,分享半个互联网人的技术与思考，感兴趣的可以关注.  
![404Code][]

[Java CORS Filter Example]: https://howtodoinjava.com/servlets/java-cors-filter-example/
[Spring CORS _ Spring _CrossOrigin example]: https://howtodoinjava.com/spring5/webmvc/spring-mvc-cors-configuration/
[CORS with Spring]: https://www.baeldung.com/spring-cors
[https_github.com_Flying9001_springBootDemo]: https://github.com/Flying9001/springBootDemo
[404Code]: /images/20220128/e3a59fb8f8ad4d09860ba2068214ecc1.png