Day05-Java开发所需的前端技术

session原理（适用于单体的身份效验）

Http 无状态，有会话

• 无状态是指，请求之间相互独立，第一次请求的数据，第二次请求不能重用
• 有会话是指，客户端和服务端都有相应的技术，可以暂存数据，让数据在请求见共享

服务端使用了session技术来暂存数据

存

GET /s1?name=zhang HTTP/1.1
Host: localhost

取

GET /s2 HTTP/1.1
Host: localhost
Cookie: JSESSIONID=BF219FEFB6FF6960ODA2537CDDED6C393

    @RequestMapping("/s1")
    @ResponseBody
    public String s1(HttpSession session, String name) {
        session.setAttribute("name", name);
        return "数据已存储";
    }

    @RequestMapping("/s2")
    @ResponseBody
    public String s2(HttpSession session) {
        return "取出数据" + session.getAttribute("name");
    }

jwt原理（适用于分布式的登录校验）

生成token

GET /j1?name=zhang&pass=123 HTTP/1.1
Host: 1ocaThost

校验token

GET /j2 HTTP/1.1
Host: localhost
Authorization:
eyjhbGcioiJIuzIlNij9.eyJzdwIioijhzGlpbij9.G4Xp74sX4dEC-KIwhK2kRmj1w157nSAROOBMspQ-1o8

    @RequestMapping("/j1")
    @ResponseBody
    public String j1(String name, String pass) {
        Calendar instance = Calendar.getInstance();
        //令牌过期时间 20s
        instance.add(Calendar.SECOND,20);
        if ("zhang".equals(name) && "123".equals(pass)) {
            String token = JWT.create()
                    .withClaim("name", name)
                    .withClaim("pass", pass)
                    .withExpiresAt(instance.getTime())
                    .sign(Algorithm.HMAC256("BUTU"));
            return "验证身份通过"+token;
        }else {
            return "验证身份失败";
        }
    }

    @RequestMapping("/j1")
    @ResponseBody
    public String j2(@RequestHeader String authorization) {
        //通过签名生成验证对象
        JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256("BUTU")).build();
        DecodedJWT verify = jwtVerifier.verify(authorization);
        return "name:"+verify.getClaim("name")+"\n"+"pass:"+verify.getClaim("pass");

    }