1. 会话技术

2. JWT令牌

3. 过滤器Filter

4. 拦截器 interceptor

cookise

package com.it.controller;

import com.it.pojo.Result;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Slf4j
@RestController
public class SessionController {
    //设置cookie
    @GetMapping("/c1")
    public Result cookie1(HttpServletResponse response){
        response.addCookie(new Cookie("login_username","it"));  //设置cookie /响应cookie
        return Result.success();
    }

    //获取cookie
    @GetMapping("/c2")
    public Result cookie2(HttpServletRequest request){

        Cookie[] cookies = request.getCookies();//获取所有的cookie
        for (Cookie cookie : cookies) {
            if (cookie.equals("login_username")){      //输出name为login_username 的cookie
                System.out.println("login_username:"+cookie.getValue());

            }

        }
            return Result.success();
    }

}

session

    //往httpSession中存储值
    @GetMapping("/s1")
    public Result sessio1(HttpSession session){
        log.info("HttpSession-s1 :{}",session.hashCode());
        session.setAttribute("loginUser","mamat");
        return  Result.success();
    }


    // 往HttpSession 中的取值
    @GetMapping("/s2")
    public Result session2(HttpServletRequest request){
        HttpSession session =request.getSession();
        log.info("HttpSession-s2:{}",session);

     Object loginUser=   session.getAttribute("loginUser") ;    //从session获取数据
    log.info("loginUser:{}",loginUser);
    return Result.success(loginUser);
    }

 jwt令牌 引入依赖

 <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt</artifactId>
            <version>0.9.1</version>
        </dependency>

package com.it.utils;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

import java.util.Date;
import java.util.Map;

public class JwtUtils {
    public static String signKey ="itWord";  //密钥
    public static Long expire = 43200000L;  //密钥   一分钟等于1000 毫秒     （43200000L 12小时）


    //生成JWT令牌y
    public static String generateJwt(Map<String,Object> claims){
       String jwt= Jwts.builder()
                .addClaims(claims)
               .signWith(SignatureAlgorithm.HS256,signKey)
               .setExpiration(new Date(System.currentTimeMillis()+expire))
               .compact();
       return jwt;
    }

    //解析JWT令牌
    public static Claims parseJWT(String jwt){
         Claims claims =Jwts.parser()
                .setSigningKey(signKey)
                .parseClaimsJwt(jwt)
                .getBody();
        return  claims;
    }
}

JWT令牌生成调用

    @PostMapping("/login")
    public Result login(@RequestBody Emp emp){
    log.info("员工登录，:{}",emp);
     Emp emp1 =empservice.login(emp);
     // 登录成功 生成令牌 下发令牌
        if (emp1!=null){
            Map<String, Object> claims =new HashMap<>();
            claims.put("id",emp1.getId());
            claims.put("name",emp1.getName());
            claims.put("username",emp1.getUsername());  // jwt令牌包含当前登录的员工信息

            String jwt = JwtUtils.generateJwt(claims);
            return Result.success(jwt);
        }
        return Result.error("用户名或者密码错误");

    }

过滤器拦截调用

package com.it.filter;

import com.alibaba.fastjson.JSONObject;

import com.it.pojo.Result;
import com.it.utils.JwtUtils;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.StringUtils;

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



@Slf4j
@WebFilter(urlPatterns = "/*")
public class LoginCheckFilter implements Filter {

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //强转
        HttpServletRequest rep=(HttpServletRequest) servletRequest;
        HttpServletResponse resp=(HttpServletResponse) servletResponse;

        // 1:获取请求url
        String url = rep.getRequestURI().toString();
        log.info("请求路径:{}",url);

        // 2:判断请求URl中是否包含login， 如果包含说明登录操作 可以放行
        if (url.contains("login")){
            log.info("登录操作 ,放行");
            filterChain.doFilter(servletRequest,servletResponse);
            return;
        }
        // 3: 获取请求头中的令牌（token）
        String jwt = rep.getHeader("token");
        log.info("Jwt,令牌数据:{}",jwt);

        // 4: 判断令牌是否存在 ，如果不存在，返回错误结果 （未登录）
        if (!StringUtils.hasLength(jwt)){
            log.info("请求头token为空 返回未登录信息");
            Result error  = Result.error("NOT_LOGIN");
            // 手动转换对象-- json ----->阿里巴巴fastJson
            String notLogin = JSONObject.toJSONString(error);
            resp.getWriter().write(notLogin);
            return;

        }
        // 5：解析token， 如果解析失败 。返回错误结果（未登录）
        try {
            JwtUtils.parseJWT(jwt);
        } catch (Exception e) {   //jwt 解析失败
            e.printStackTrace();
            log.info("解析令牌解析失败 返回未登录错误信息");
            Result error  = Result.error("NOT_LOGIN");
            // 手动转换对象-- json ----->阿里巴巴fastJson
            String notLogin = JSONObject.toJSONString(error);
            resp.getWriter().write(notLogin);
            return;
        }



        // 6：放行
        log.info("令牌合法 放行");
        filterChain.doFilter(servletRequest,servletResponse);

    }
}