{
	"username": "jinyong",
    "password": "123456"
}

{
  "code": 1,
  "msg": "success",
  "data": "eyJhbGciOiJIUzI1NiJ9.eyJuYW1lIjoi6YeR5bq4IiwiaWQiOjEsInVzZXJuYW1lIjoiamlueW9uZyIsImV4cCI6MTY2MjIwNzA0OH0.KkUc_CXJZJ8Dd063eImx4H9Ojfrr6XMJ-yVzaWCVZCo"
}

{
	"code": 0,
	"msg": "NOT_LOGIN",
	"data": null
}

@Slf4j
@WebFilter(urlPatterns = "/*") //攔截所有請(qǐng)求
public class LoginCheckFilter implements Filter {

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain) throws IOException, ServletException {
        //前置：強(qiáng)制轉(zhuǎn)換為http協(xié)議的請(qǐng)求對(duì)象、響應(yīng)對(duì)象 （轉(zhuǎn)換原因：要使用子類(lèi)中特有方法）
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        //1.獲取請(qǐng)求url
        String url = request.getRequestURL().toString();
        log.info("請(qǐng)求路徑：{}", url); //請(qǐng)求路徑：http://localhost:8080/login


        //2.判斷請(qǐng)求url中是否包含login，如果包含，說(shuō)明是登錄操作，放行
        if(url.contains("/login")){
            chain.doFilter(request, response);//放行請(qǐng)求
            return;//結(jié)束當(dāng)前方法的執(zhí)行
        }


        //3.獲取請(qǐng)求頭中的令牌（token）
        String token = request.getHeader("token");
        log.info("從請(qǐng)求頭中獲取的令牌：{}",token);


        //4.判斷令牌是否存在，如果不存在，返回錯(cuò)誤結(jié)果（未登錄）
        if(!StringUtils.hasLength(token)){
            log.info("Token不存在");

            Result responseResult = Result.error("NOT_LOGIN");
            //把Result對(duì)象轉(zhuǎn)換為JSON格式字符串 (fastjson是阿里巴巴提供的用于實(shí)現(xiàn)對(duì)象和json的轉(zhuǎn)換工具類(lèi))
            String json = JSONObject.toJSONString(responseResult);
            response.setContentType("application/json;charset=utf-8");
            //響應(yīng)
            response.getWriter().write(json);

            return;
        }

        //5.解析token，如果解析失敗，返回錯(cuò)誤結(jié)果（未登錄）
        try {
            JwtUtils.parseJWT(token);
        }catch (Exception e){
            log.info("令牌解析失敗!");

            Result responseResult = Result.error("NOT_LOGIN");
            //把Result對(duì)象轉(zhuǎn)換為JSON格式字符串 (fastjson是阿里巴巴提供的用于實(shí)現(xiàn)對(duì)象和json的轉(zhuǎn)換工具類(lèi))
            String json = JSONObject.toJSONString(responseResult);
            response.setContentType("application/json;charset=utf-8");
            //響應(yīng)
            response.getWriter().write(json);

            return;
        }


        //6.放行
        chain.doFilter(request, response);

    }
}

<!--JWT令牌-->
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt</artifactId>
            <version>0.9.1</version>
        </dependency>

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import java.util.Date;
import java.util.Map;

public class JwtUtils {

    private static String signKey = "shisan";
    private static Long expire = 43200000L;

    /**
     * 生成JWT令牌
     * @param claims JWT第二部分負(fù)載 payload 中存儲(chǔ)的內(nèi)容
     * @return
     */
    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
     * @param jwt JWT令牌
     * @return JWT第二部分負(fù)載 payload 中存儲(chǔ)的內(nèi)容
     */
    public static Claims parseJWT(String jwt){
        Claims claims = Jwts.parser()
                .setSigningKey(signKey)
                .parseClaimsJws(jwt)
                .getBody();
        return claims;
    }
}

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.76</version>
</dependency>