JWT

JSON Web Token (JWT)是一个开放标准(RFC 7519)，它定义了一种紧凑的、自包含的方式，用于作为JSON对象在各方之间安全地传输信息。该信息可以被验证和信任，因为它是数字签名的

依赖

<!-- JWT token -->
<dependency>
    <groupId>com.auth0</groupId>
    <artifactId>java-jwt</artifactId>
    <version>3.2.0</version>
</dependency>

<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt</artifactId>
    <version>0.7.0</version>
</dependency>

生成JWT

public static String tokencreate(Object de){
    //当前时间
    Date now=new Date();
    //1小时
    long last=now.getTime()+120*1000;
    //过期时间2分钟
    Date expir=new Date(last);

    JwtBuilder builder= Jwts.builder()
            /*.setId("1")*/
            //存放的内容
            /*.setSubject(usde)*/
            //生成的时间
            .setIssuedAt(now)
            //过期时间
            .setExpiration(expir)
            //可以存对象
            .claim("login",de)
            //加密方式
            .signWith(SignatureAlgorithm.HS256,"xianxian");
    //生成token
    String token= builder.compact();
    return token;
}

解析JWT

主要解析JWT代码

Claims cl=Jwts.parser().setSigningKey("xianxian").parseClaimsJws(oldtoken).getBody();

当JWT错误或者过期时则会报错

@Test
public void decrypt() throws JsonProcessingException {
    //原来生成的token
    String oldtoken="eyJhbGciOiJIUzI1NiJ9.eyJqdGkiOiIxIiwic3ViIjoie1wiaWRcIjoxLFwibmFtZVwiOlwi5qCI5LiJXCIsXCJiaXJ0aGRhdGVcIjoxNjM4NDk1MzEzNzc0fSIsImlhdCI6MTYzODQ5NTMxMywiZXhwIjoxNjM4NDk4OTEzLCJsb2dpbiI6eyJpZCI6MSwibmFtZSI6IuagiOS4iSIsImJpcnRoZGF0ZSI6MTYzODQ5NTMxMzc3NH19.tQqtSVqgwLFcuuKn1kv_I4B0_ymBY-LUPHz8Z2nPP7U";
    //setSigningKey(加密方式的key )   parseClaimsJws(原来生成的token)
    Claims cl=Jwts.parser().setSigningKey("xianxian").parseClaimsJws(oldtoken).getBody();
    LinkedHashMap lmap= (LinkedHashMap) cl.get("login");
    System.out.println(cl.get("login"));
    System.out.println("id:"+lmap.get("id"));
    System.out.println("iat:"+cl.get("iat"));
    System.out.println(cl);
    //获取Subject
    System.out.println("sub:"+cl.getSubject());
    ObjectMapper obj=new ObjectMapper();
    //把subj里面的转换成对象
    Userdemo us=obj.readValue(cl.getSubject(),Userdemo.class);
    System.out.println(us);
    System.out.println(us.getBirthdate());
}

跨域和拦截器配置类

package com.it.seckill.config;
import com.it.seckill.Interceptor.LoginInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
/**
 * @Author: 羡羡
 * @Date: 2021/12/02/10:39
 */
@Configuration
public class WebConfig implements WebMvcConfigurer {
    @Autowired
    LoginInterceptor login;
    /**
     * 跨域
     * @param registry
     */
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        //所有
        registry.addMapping("/**")
                //支持的方法
                /*.allowedOrigins("*")*/
                .allowedOriginPatterns("*")
                //支持的方法
                .allowedMethods("GET","PUT","DELETE","POST","HEAD","OPTIONS")
                //证书
                .allowCredentials(true)
                //超时
                .maxAge(3600)
                //允许头
                .allowedHeaders("*");
    }
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //增加拦截器
        registry.addInterceptor(login)
                //拦截的路径
                .addPathPatterns("/**")
                //排除的路径
                .excludePathPatterns("/selogin");
    }
}

拦截器

拦截器不拦截登入 但是会解析请求头

package com.it.seckill.Interceptor;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

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

/**
 * @Author: 羡羡
 * @Date: 2021/12/03/10:03
 */
@Component
public class LoginInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String method=request.getMethod();
        if(!method.equalsIgnoreCase("GET") && !method.equalsIgnoreCase("POST")){
            return true;
        }
        System.out.println("login标志！");
        //会的前台的请求头token
        String token=request.getHeader("token");
        //解析JWT
        Claims cl= Jwts.parser().setSigningKey("xianxian").parseClaimsJws(token).getBody();
        System.out.println("检查Token:"+token);
        //判断拦截
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

控制器

登入成功时就会生成token令牌 发送到前台

package com.it.seckill.controller;
/**
 * @Author: 羡羡
 * @Date: 2021/12/02/19:39
 *
 * 连接了数据库
 */
@RestController
public class SeckillControllerSQL {

    @Autowired
    UserService use;

    @Autowired
    GoodsService gos;

    /**
     * 用户登入
     * @param us
     * @param pa
     * @return
     */
    @RequestMapping("/selogin")
    public JsonResult selogin(String us,String pa){
        JsonResult js;
        User user=new User();
        user.setUsname(us);
        user.setUspass(pa);
        User usevi=use.login(user);
        if(usevi!=null){
            //生成令牌
            String token=TokenTools.tokencreate(usevi);
            js=new JsonResult(200,"登入成功！",token);
        }else{
            js=new JsonResult(500,"登入失败！");
        }
        return js;
    }



    /**
     * 查询所有商品
     * @return
     */
    @RequestMapping("/seckillall")
    public JsonResult seall(){
        List lis=gos.seall();
        JsonResult js=new JsonResult(200,"成功！",lis);
        return js;
    }
}

前台登入

当登入成功后就会获取token 把token保存到 localStorage中

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <h1>登入页</h1>
    UserName：<input type="text" name="usname" id="na" required/><br /><br />
    Password：<input type="password" name="password" id="pwd" required/><br /><br />
    <button type="submit" name="">提交</button>
  </body>
  <script>
      $(function(){
          $("button").click(function(){
              var ac=$("#na").val();
              var pa=$("#pwd").val();
              var data ={
                  "us":ac,
                  "pa":pa
              }
              $.post("http://127.0.0.1:8090/selogin",data,function(da){
                  //登入成功
                  if(da.code == "200"){
                    localStorage.setItem("mstoken",da.data);
                    $("a").eq(0).text("退出登入");
                      //加载首页
                    $(".app").load("main.html");
                  }else{
                      alert("登入失败！");
                  }
              })
          })
      })
  </script>
</html>

前台显示内容

加载完界面后 取出存到浏览器的localStorage 发送请求到后台 带一个tonken

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <h1>主页面</h1>
    <div id="cd1">
      <table border="1px" style="text-align: center;">
      </table>
    </div>
  </body>
  <script>
    $(function () {
    //取出token
      var mstoken=localStorage.getItem("mstoken");
      $.ajax({
      //请求头
        headers:{
          token:mstoken
        },
        url: "http://127.0.0.1:8090/seckillall",
        type: "POST",
        success: function (da) {
          if(da.code=="500"){
            alert("服务器错误！");
          }else{
            var tr="<tr><td>商品名称</td><td>商品数量</td><td>开抢时间</td></tr>";
            for(var i=0;i<da.data.length;i++){
                tr+="<tr><td>"+da.data[i].name+"</td><td>"+da.data[i].number+"</td><td>"+da.data[i].startTime+"</td></tr>";
            }
            $("#cd1 table").html(tr);
          }
        },
      });
    });
  </script>
</html>