问题描述

在Springboot中添加过滤器来进行请求拦截配置

解决方案：

1、在启动类上加上@ServletComponentScan//扫描过滤器使用

2、创建filter包专业放过滤器

3、在该包中创建过滤器

@Slf4j
@WebFilter(filterName = "loginCheckFilter",urlPatterns = "/*")
public class LoginCheckFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;//向上转型
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        log.info("拦截请求: {}",request.getRequestURI());//这个是日志信息，直接输出拦截的请求
		//这里书写业务逻辑！！！
        filterChain.doFilter(request,response);//放行
    }
}

4、然后在该类中书写写逻辑业务,这里以登录拦截为例,配合前端vue的响应拦截器书写的！

/**
 * 检查用户是否完成登录
 * @author mrs
 * @create 2022-05-31 10:57
 */
@Slf4j
@WebFilter(filterName = "loginCheckFilter",urlPatterns = "/*")//先全部拦截
public class LoginCheckFilter implements Filter {
    //路径匹配器
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;//向上转型
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        //1、获取前端的本次请求的URI
        String requestURI = request.getRequestURI();
        String[] urls = new String[]{//列举放行资源
                "/employee/login",//放行登录请求
                "/employee/login",//放行注册请求
                "/backend/**",//放行静态资源和静态页面
                "/front/**"
        };
        //2、判断本次请求是否需要处理
        boolean check = check(requestURI, urls);
        //3、如果不需要处理,则直接放行
        if(check){
            filterChain.doFilter(request,response);//放行
            return;
        }
        //4、判断登录状态,如果已登录,则直接放行
        if(request.getSession().getAttribute("employee") != null){
            filterChain.doFilter(request,response);//放行
            return;
        }
        //5、如果未登录则返回未登录结果,通过输出流的方式向客户端页面响应数据
        // 这里响应的是backend/js/request.js中的响应拦截器
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
    }

    /**
     * 路径匹配,检查本次请求是否放行
     * @param requetURI 从前端传回的请求
     * @param urls 上面不用拦截的请求
     * @return 进行对比返回
     */
    public boolean check(String requetURI,String[] urls){
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requetURI);//使用上面定义的路径匹配器,进行比对
            if(match){
                return true;//匹配成功就返回true
            }
        }
        return false;//一个也没匹配上,返回false
    }
}