spring boot 使用filter 實現跨域請求

spring boot 使用filter 實現跨域請求

1.請求處理流程

Filter->DispatcherServlet->Intercepter->Controller

2.配置掃描filter

在SpringBootApplication上使用@ServletComponentScan注解后，Servlet、Filter、Listener可以直接通過@WebServlet、@WebFilter、@WebListener注解自動注冊，無需其他代碼。

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;

@ServletComponentScan("com.itstudies.myservice.filters")
@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication app = new SpringApplication(Application.class);
        app.run(args);
    }
}

3.自定義CrossFilter

package com.itstudies.myservice.filters;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebFilter("/*")
public class MyCrossFilter implements Filter {

    private Logger logger = LoggerFactory.getLogger(MyCrossFilter.class);

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

        HttpServletResponse res = (HttpServletResponse) response;
        HttpServletRequest req = (HttpServletRequest) request;
        String origin = req.getHeader("Origin");

        if (!org.springframework.util.StringUtils.isEmpty(origin)) {
            //帶cookie的時候，origin必須是全匹配，不能使用*
            res.addHeader("Access-Control-Allow-Origin", origin);
        }
        res.addHeader("Access-Control-Allow-Methods", "*");
        String headers = req.getHeader("Access-Control-Request-Headers");
        // 支持所有自定義頭
        if (!org.springframework.util.StringUtils.isEmpty(headers)) {
            res.addHeader("Access-Control-Allow-Headers", headers);
        }
        res.addHeader("Access-Control-Max-Age", "3600");
        // enable cookie
        res.addHeader("Access-Control-Allow-Credentials", "true");

        //處理options請求
        if (req.getMethod().toUpperCase().equals("OPTIONS")) {
            return;
        }

        //獲取token
        //String auth = req.getHeader("Authorization");
        String auth = req.getHeader("token");

        chain.doFilter(request, response);
    }

    @Override
    public void destroy() {

    }
}