<!-- JWT依賴 -->
<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt</artifactId>
    <version>0.7.0</version>
</dependency>
<dependency>
    <groupId>com.auth0</groupId>
    <artifactId>java-jwt</artifactId>
    <version>3.4.0</version>
</dependency>

server:
  port: 8080
spring:
  application:
    name: springboot-jwt
config:
  jwt:
    # 加密密鑰
    secret: abcdefg1234567
    # token有效時(shí)長(zhǎng)
    expire: 3600
    # header 名稱
    header: token

package com.example.config;
 
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import java.util.Date;
 
/**
 * JWT的token，區(qū)分大小寫
 */
@ConfigurationProperties(prefix = "config.jwt")
@Component
public class JwtConfig {
 
    private String secret;
    private long expire;
    private String header;
 
    /**
     * 生成token
     * @param subject
     * @return
     */
    public String createToken (String subject){
        Date nowDate = new Date();
        Date expireDate = new Date(nowDate.getTime() + expire * 1000);//過期時(shí)間
 
        return Jwts.builder()
                .setHeaderParam("typ", "JWT")
                .setSubject(subject)
                .setIssuedAt(nowDate)
                .setExpiration(expireDate)
                .signWith(SignatureAlgorithm.HS512, secret)
                .compact();
    }
    /**
     * 獲取token中注冊(cè)信息
     * @param token
     * @return
     */
    public Claims getTokenClaim (String token) {
        try {
            return Jwts.parser().setSigningKey(secret).parseClaimsJws(token).getBody();
        }catch (Exception e){
//            e.printStackTrace();
            return null;
        }
    }
    /**
     * 驗(yàn)證token是否過期失效
     * @param expirationTime
     * @return
     */
    public boolean isTokenExpired (Date expirationTime) {
        return expirationTime.before(new Date());
    }
 
    /**
     * 獲取token失效時(shí)間
     * @param token
     * @return
     */
    public Date getExpirationDateFromToken(String token) {
        return getTokenClaim(token).getExpiration();
    }
    /**
     * 獲取用戶名從token中
     */
    public String getUsernameFromToken(String token) {
        return getTokenClaim(token).getSubject();
    }
 
    /**
     * 獲取jwt發(fā)布時(shí)間
     */
    public Date getIssuedAtDateFromToken(String token) {
        return getTokenClaim(token).getIssuedAt();
    }
 
    // --------------------- getter & setter ---------------------
 
    public String getSecret() {
        return secret;
    }
    public void setSecret(String secret) {
        this.secret = secret;
    }
    public long getExpire() {
        return expire;
    }
    public void setExpire(long expire) {
        this.expire = expire;
    }
    public String getHeader() {
        return header;
    }
    public void setHeader(String header) {
        this.header = header;
    }
}

package com.example.interceptor;
 
import com.example.config.JwtConfig;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.SignatureException;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
@Component
public class TokenInterceptor extends HandlerInterceptorAdapter {
 
    @Resource
    private JwtConfig jwtConfig ;
    @Override
    public boolean preHandle(HttpServletRequest request,
                             HttpServletResponse response,
                             Object handler) throws SignatureException {
        /** 地址過濾 */
        String uri = request.getRequestURI() ;
        if (uri.contains("/login")){
            return true ;
        }
        /** Token 驗(yàn)證 */
        String token = request.getHeader(jwtConfig.getHeader());
        if(StringUtils.isEmpty(token)){
            token = request.getParameter(jwtConfig.getHeader());
        }
        if(StringUtils.isEmpty(token)){
            throw new SignatureException(jwtConfig.getHeader()+ "不能為空");
        }
 
        Claims claims = null;
        try{
            claims = jwtConfig.getTokenClaim(token);
            if(claims == null || jwtConfig.isTokenExpired(claims.getExpiration())){
                throw new SignatureException(jwtConfig.getHeader() + "失效，請(qǐng)重新登錄。");
            }
        }catch (Exception e){
            throw new SignatureException(jwtConfig.getHeader() + "失效，請(qǐng)重新登錄。");
        }
 
        /** 設(shè)置 identityId 用戶身份ID */
        request.setAttribute("identityId", claims.getSubject());
        return true;
    }
}

package com.example.config;
 
import com.example.interceptor.TokenInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import javax.annotation.Resource;
 
@Configuration
public class WebConfig implements WebMvcConfigurer {
    @Resource
    private TokenInterceptor tokenInterceptor ;
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(tokenInterceptor).addPathPatterns("/**");
    }
}

package com.example.config;
import io.jsonwebtoken.SignatureException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.yuyi.full.handler.exception.ExceptionInfoBO;
import org.yuyi.full.handler.exception.ResultBO;
import org.yuyi.full.handler.exception.ResultTool;
 
@RestControllerAdvice
public class PermissionHandler {
    @ExceptionHandler(value = { SignatureException.class })
    @ResponseBody
    public ResultBO<?> authorizationException(SignatureException e){
        return ResultTool.error(new ExceptionInfoBO(1008,e.getMessage()));
    }
}

package com.example.controller;
 
import com.alibaba.fastjson.JSONObject;
import com.example.config.JwtConfig;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.yuyi.full.handler.exception.ResultBO;
import org.yuyi.full.handler.exception.ResultTool;
import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import java.util.HashMap;
import java.util.Map;
 
@RestController
public class TokenController {
 
    @Resource
    private JwtConfig jwtConfig ;
 
    /**
     * 用戶登錄接口
     * @param userName
     * @param passWord
     * @return
     */
    @PostMapping("/login")
    public ResultBO<?> login (@RequestParam("userName") String userName,
                           @RequestParam("passWord") String passWord){
        JSONObject json = new JSONObject();
 
        /** 驗(yàn)證userName，passWord和數(shù)據(jù)庫(kù)中是否一致，如不一致，直接return ResultTool.errer(); 【這里省略該步驟】*/
 
        // 這里模擬通過用戶名和密碼，從數(shù)據(jù)庫(kù)查詢userId
        // 這里把userId轉(zhuǎn)為String類型，實(shí)際開發(fā)中如果subject需要存userId，則可以JwtConfig的createToken方法的參數(shù)設(shè)置為L(zhǎng)ong類型
        String userId = 5 + "";
        String token = jwtConfig.createToken(userId) ;
        if (!StringUtils.isEmpty(token)) {
            json.put("token",token) ;
        }
        return ResultTool.success(json) ;
    }
 
    /**
     * 需要 Token 驗(yàn)證的接口
     */
    @PostMapping("/info")
    public ResultBO<?> info (){
        return ResultTool.success("info") ;
    }
 
    /**
     * 根據(jù)請(qǐng)求頭的token獲取userId
     * @param request
     * @return
     */
    @GetMapping("/getUserInfo")
    public ResultBO<?> getUserInfo(HttpServletRequest request){
        String usernameFromToken = jwtConfig.getUsernameFromToken(request.getHeader("token"));
        return ResultTool.success(usernameFromToken) ;
    }
 
    /*
        為什么項(xiàng)目重啟后，帶著之前的token還可以訪問到需要info等需要token驗(yàn)證的接口？
        答案：只要不過期，會(huì)一直存在，類似于redis
     */
 
}