使用JWT生成token

最新推荐文章于 2025-07-03 17:49:09 发布

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最新推荐文章于 2025-07-03 17:49:09 发布

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本文详细介绍了如何在Java应用中使用JWT（JSON Web Tokens）进行用户认证。首先，介绍了导入必要的JWT库，然后展示了如何编写生成token的工具类。接着，通过UserController来演示如何在用户登录后生成Token。最后，通过MeController进行测试，检查生成的Token的有效性和过期机制。

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1、导包（在idea中的应用）

<!-- jwt token的使用-->
    <dependency>
      <groupId>com.auth0</groupId>
      <artifactId>java-jwt</artifactId>
      <version>2.2.0</version>
    </dependency>

2、写生成token的工具类（JWT）

import java.util.HashMap;
import java.util.Map;

import com.auth0.jwt.JWTSigner;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.internal.com.fasterxml.jackson.databind.ObjectMapper;

public class JWT {

    private static final String SECRET = "XX#$%()(#*!()!KL<><MQLMNQNQJQK sdfkjsdrow32234545fdf>?N<:{LWPW";//额外的盐

    private static final String EXP = "exp";

    private static final String PAYLOAD = "payload";//负荷

    /**
     * get jwt String of object
     * @param object
     *            the POJO object
     * @param maxAge
     *            the milliseconds of life time
     * @return the jwt token
     */
    public static <T> String sign(T object, long maxAge) {
        try {
            final JWTSigner signer = new JWTSigner(SECRET);
            final Map<String, Object> claims = new HashMap<String, Object>();
            ObjectMapper mapper = new ObjectMapper();
            String jsonString = mapper.writeValueAsString(object);
            claims.put(PAYLOAD, jsonString);
            claims.put(EXP, System.currentTimeMillis() + maxAge);//失效时间
            return signer.sign(claims);
        } catch(Exception e) {
            return null;
        }
    }


    /**
     * get the object of jwt if not expired
     * @param jwt
     * @return POJO object
     */
    public static<T> T unsign(String jwt, Class<T> classT) {
        final JWTVerifier verifier = new JWTVerifier(SECRET);
        try {
            final Map<String,Object> claims= verifier.verify(jwt);
            if (claims.containsKey(EXP) && claims.containsKey(PAYLOAD)) {
                long exp = (Long)claims.get(EXP);
                long currentTimeMillis = System.currentTimeMillis();
                if (exp > currentTimeMillis) {
                    String json = (String)claims.get(PAYLOAD);
                    ObjectMapper objectMapper = new ObjectMapper();
                    return objectMapper.readValue(json, classT);//表示可用
                }
            }
            return null;//表示失效
        } catch (Exception e) {
            return null;
        }
    }
}

3、生成token(UserController)

@Controller
public class UserController {
    @RequestMapping("/login")
    @ResponseBody
    public ResultBean login(@RequestParam String username, @RequestParam String password) {
        if ("haha".equals(username) && "123456".equals(password)) {
            User user=new User();
            user.setId("1");
            user.setName(username);
            user.setPassword(password);

           /* responseData.putDataValue("user", user);*/
            String token = JWT.sign(user, 30L * 24L * 3600L * 1000L);//一个月的时间
            if (token != null) {
                return new ResultBean("0",token);
            }
        }
        return new ResultBean("0","用户名或密码错误");
    }
}

ResultBean 工具类

@Data
public class ResultBean implements Serializable {
    private static final long serialVersionUID = 1L;

    private String code = "0"; // code
    private String msg = ""; // msg
    private long count; // count
    private List data; // data

    public ResultBean() {
    }

    public ResultBean(List data) {
        if (data instanceof Page) {
            Page page = (Page) data;
            this.count = page.getTotal();
        } else {
            this.count = data.size();
        }
        this.data = data;
    }
    public ResultBean(List data, long count) {
        this.data = data;
        this.count=count;
    }

    public ResultBean(String code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    public ResultBean(String code, String msg, List data) {
        this.code = code;
        this.msg = msg;
        if (data instanceof Page) {
            Page page = (Page) data;
            this.count = page.getTotal();
        } else {
            this.count = data.size();
        }
        this.data = data;
    }

    public ResultBean(String code, String msg, long count, List data) {
        this.code = code;
        this.msg = msg;
        if (data instanceof Page) {
            Page page = (Page) data;
            this.count = page.getTotal();
        } else {
            this.count = data.size();
        }
        this.data = data;
    }
}

4、测试生成的token是否可用或失效(MeController)

@Controller
@RequestMapping("/me")
public class MeController {

    @RequestMapping("/get_info")
    @ResponseBody
    public ResultBean getInfo(@RequestParam String token) {
        User user = JWT.unsign(token, User.class);
        if (user != null) {
            return new ResultBean("0","成功了。。。。");
        }
        return new ResultBean("1","token不合法");
    }
}