java跨域过滤器

环境描述

前端：angular
后台：springboot

问题

前端调用后台接口出现跨域的问题，具体内容笔者没有截图，如果出现问题在网站页面的console中可以看到

解决

后台新建一个类，添加过滤器

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebFilter(filterName = "cors", urlPatterns = "/*")
public class CORSFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;
        System.out.println(request.getHeaderNames());
        response.setHeader("Access-Control-Allow-Origin", request.getHeader("Origin"));
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.addHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept,token");
        response.setHeader("Access-Control-Allow-Credentials", "true");
        chain.doFilter(req, res);
    }

    @Override
    public void destroy() {

    }
}

再试试前台访问，看看是否还会出现跨域问题。

----------------------------------10.26更新---------------------------------------------

笔者在开发过程中碰到了灵异现象，用post方式调用，且接收参数为@RequestBody的时候，这个方法就会跨域，其他的调用方式不跨域，经过查阅资料，更新上面的代码如下

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebFilter(filterName = "cors", urlPatterns = "/*")
public class CORSFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;
        System.out.println(request.getHeaderNames());
        response.setHeader("Access-Control-Allow-Origin", request.getHeader("Origin"));
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.addHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept,token");
        response.setHeader("Access-Control-Allow-Credentials", "true");
        if ("OPTIONS".equals(request.getMethod())) {
            res.getWriter().println("ok");
            return;
        }
        chain.doFilter(req, res);
    }

    @Override
    public void destroy() {

    }
}