vue-admin-template 目录

说明

需要依赖 jackson 库，将 java 对象转成 json字符串

代码

登录过滤器

• 跨域时，非简单请求，会发送 OPTIONS 请求，需要判断该请求，并直接放行

• 从 session 中取出用户信息对象，并判断是否登录

package com.zrgj.epidemic.filter;


import com.zrgj.epidemic.pojo.Result;
import com.zrgj.epidemic.util.ResponseUtil;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

@WebFilter(urlPatterns = {"/*"})
public class LoginFilter implements Filter {

    private static List<String> notFilterList = new ArrayList();
    static {
        notFilterList.add("/login");
    }

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {

        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) resp;
        String method = request.getMethod();
        System.out.println("method:"+method);

        //跨域会发送 OPTIONS 请求，该请求header中没有auth，直接放行
        if("OPTIONS".equals(method)){
            chain.doFilter(req,resp);
            return;
        }

        boolean res = isNotFilter(request);
        if(res){
            chain.doFilter(req,resp);
            return;
        }

        HttpSession session = request.getSession();

        if(session.getAttribute("user") == null){

            Result result = new Result();
            result.setFlag(false);
            result.setMessage("您未登录或登录超时，请重新登录！");
            ResponseUtil.sendJSON(response,result);

        }else{
            chain.doFilter(req, resp);
        }

    }
    /**
     * 判断该路径是否需要过滤
     * @param request false，不需要过滤；true，需要过滤
     * @return
     */
    private boolean isNotFilter(HttpServletRequest request){
        String servletPath = request.getServletPath();

        // 问1：如何在过滤器中，知道访问的是 静态文件（内容不会变的文件：.html、.css、.jpg、.gif）
//        String uri = request.getRequestURI();
//        System.out.println("uri:"+servletPath);

        // 问2：如何刨除去这些请求，不经过过滤器

        for(String item : notFilterList){
            item = item.replaceAll("\\.","\\\\.");
            item = item.replaceAll("\\*","\\.\\*");
            boolean res = servletPath.matches(item);
            if(res){
                return true;
            }
        }

        return false;
    }
}

Result 类

package com.zrgj.epidemic.pojo;

import lombok.Data;

import java.util.List;

@Data
public class Result<E> {
    /**
     * 0表示成功
     */
    private int status;
    private String message;
    private String code;
    private E object;
    private boolean flag;
    private List<E> list;

}

ResponseUtil

将 java 对象转成 json 字符串，并发送到浏览器

public class ResponseUtil {

    public static void sendJSON(HttpServletResponse response,Object obj) throws IOException {

        // 调用 jackson，将javabean转换成json字符串
        ObjectMapper om=new ObjectMapper();
        String json=om.writeValueAsString(obj);
        response.getWriter().println(json);
    }
}