spring boot 2 集成JWT實現api接口認證

JSON Web Token（JWT）是目前流行的跨域身份驗證解決方案。
官網：https://jwt.io/
本文使用spring boot 2 集成JWT實現api接口驗證。

一、JWT的數據結構

JWT由header（頭信息）、payload（有效載荷）和signature（簽名）三部分組成的，用“.”連接起來的字符串。
JWT的計算邏輯如下：
（1）signature = HMACSHA256(base64UrlEncode(header) + "." + base64UrlEncode(payload), secret)
其中私鑰secret保存於服務器端，不能泄露出去。
（2）JWT = base64UrlEncode(header) + "." + base64UrlEncode(payload) + signature

下面截圖以官網的例子，簡單說明

二、JWT工作機制

客戶端使用其憑據成功登錄時，服務器生成JWT並返回給客戶端。
當客戶端訪問受保護的資源時，用戶代理使用Bearer模式發送JWT，通常在Authorization header中，如下所示：
Authorization: Bearer <token>
服務器檢查Authorization header中的有效JWT ，如果有效，則允許用戶訪問受保護資源。JWT包含必要的數據，還可以減少查詢數據庫或緩存信息。

三、spring boot集成JWT實現api接口驗證

開發環境：
IntelliJ IDEA 2019.2.2
jdk1.8
Spring Boot 2.1.11

1、創建一個SpringBoot項目，pom.xml引用的依賴包如下

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.auth0</groupId>
            <artifactId>java-jwt</artifactId>
            <version>3.8.3</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.10</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.62</version>
        </dependency>

2、定義一個接口的返回類

package com.example.jwtdemo.entity;


import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

import java.io.Serializable;

@Data
@NoArgsConstructor
@ToString
public class ResponseData<T> implements Serializable {
    /**
     * 狀態碼：0-成功，1-失敗
     * */
    private int code;

    /**
     * 錯誤消息，如果成功可爲空或SUCCESS
     * */
    private String msg;

    /**
     * 返回結果數據
     * */
    private T data;

    public static ResponseData success() {
        return success(null);
    }

    public static ResponseData success(Object data) {
        ResponseData result = new ResponseData();
        result.setCode(0);
        result.setMsg("SUCCESS");
        result.setData(data);
        return result;
    }

    public static ResponseData fail(String msg) {
        return fail(msg,null);
    }

    public static ResponseData fail(String msg, Object data) {
        ResponseData result = new ResponseData();
        result.setCode(1);
        result.setMsg(msg);
        result.setData(data);
        return result;
    }
}

3、統一攔截接口返回數據

package com.example.jwtdemo.config;


import com.alibaba.fastjson.JSON;
import com.example.jwtdemo.entity.ResponseData;
import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

/**
 * 實現ResponseBodyAdvice接口，可以對返回值在輸出之前進行修改
 */
@RestControllerAdvice
public class GlobalResponseHandler implements ResponseBodyAdvice<Object> {

    //判斷支持的類型
    @Override
    public boolean supports(MethodParameter methodParameter, Class<? extends HttpMessageConverter<?>> aClass) {
        return true;
    }

    @Override
    public Object beforeBodyWrite(Object o, MethodParameter methodParameter, MediaType mediaType, Class<? extends HttpMessageConverter<?>> aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {
        // 判斷爲null構建ResponseData對象進行返回
        if (o == null) {
            return ResponseData.success();
        }
        // 判斷是ResponseData子類或其本身就返回Object o本身，因爲有可能是接口返回時創建了ResponseData,這裏避免再次封裝
        if (o instanceof ResponseData) {
            return (ResponseData<Object>) o;
        }
        // String特殊處理，否則會拋異常
        if (o instanceof String) {
            return JSON.toJSON(ResponseData.success(o)).toString();
        }
        return ResponseData.success(o);
    }
}

4、統一異常處理

package com.example.jwtdemo.exception;

import com.example.jwtdemo.entity.ResponseData;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

@RestControllerAdvice
public class GlobalExceptionHandler {
    @ExceptionHandler(Exception.class)
    public ResponseData exceptionHandler(Exception e) {
        e.printStackTrace();
        return ResponseData.fail(e.getMessage());
    }
}

5、創建一個JWT工具類

package com.example.jwtdemo.common;

import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.interfaces.DecodedJWT;
import com.auth0.jwt.JWT;

import java.util.Date;

public class JwtUtils {
    public static final String TOKEN_HEADER = "Authorization";
    public static final String TOKEN_PREFIX = "Bearer ";
    // 過期時間，這裏設爲5分鐘
    private static final long EXPIRE_TIME = 5 * 60 * 1000;
    // 密鑰
    private static final String SECRET = "jwtsecretdemo";

    /**
     * 生成簽名,5分鐘後過期
     *
     * @param name 名稱
     * @param secret 密碼
     * @return 加密後的token
     */
    public static String sign(String name) {
        Date date = new Date(System.currentTimeMillis() + EXPIRE_TIME);
        Algorithm algorithm = Algorithm.HMAC256(SECRET); //使用HS256算法
        String token = JWT.create() //創建令牌實例
                .withClaim("name", name) //指定自定義聲明，保存一些信息
                //.withSubject(name) //信息直接放在這裏也行
                .withExpiresAt(date) //過期時間
                .sign(algorithm); //簽名
        return token;
    }

    /**
     * 校驗token是否正確
     *
     * @param token 令牌
     * @param secret 密鑰
     * @return 是否正確
     */
    public static boolean verify(String token) {
        try{
            String name = getName(token);
            Algorithm algorithm = Algorithm.HMAC256(SECRET);
            JWTVerifier verifier = JWT.require(algorithm)
                    .withClaim("name", name)
                    //.withSubject(name)
                    .build();
            DecodedJWT jwt = verifier.verify(token);
            return true;
        } catch (Exception e){
            return false;
        }
    }

    /**
     * 獲得token中的信息
     *
     * @return token中包含的名稱
     */
    public static String getName(String token) {
        try {
            DecodedJWT jwt = JWT.decode(token);
            return jwt.getClaim("name").asString();
        }catch(Exception e){
            return null;
        }
    }
}

6、新建兩個自定義註解：一個需要認證、另一個不需要認證

package com.example.jwtdemo.config;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface LoginToken {
    boolean required() default true;
}

package com.example.jwtdemo.config;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface PassToken {
    boolean required() default true;
}

7、新建攔截器並驗證token

package com.example.jwtdemo.config;

import com.example.jwtdemo.common.JwtUtils;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;

public class AuthenticationInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 如果不是映射到方法直接通過
        if(!(handler instanceof HandlerMethod)){
            return true;
        }
        HandlerMethod handlerMethod=(HandlerMethod)handler;
        Method method=handlerMethod.getMethod();
        //檢查是否有passtoken註釋，有則跳過認證
        if (method.isAnnotationPresent(PassToken.class)) {
            PassToken passToken = method.getAnnotation(PassToken.class);
            if (passToken.required()) {
                return true;
            }
        }
        //檢查有沒有需要用戶權限的註解
        if (method.isAnnotationPresent(LoginToken.class)) {
            LoginToken loginToken = method.getAnnotation(LoginToken.class);
            if (loginToken.required()) {
                // 執行認證
                String tokenHeader = request.getHeader(JwtUtils.TOKEN_HEADER);// 從 http 請求頭中取出 token
                if(tokenHeader == null){
                    throw new RuntimeException("沒有token");
                }
                String token = tokenHeader.replace(JwtUtils.TOKEN_PREFIX, "");
                if (token == null) {
                    throw new RuntimeException("沒有token");
                }
                boolean b = JwtUtils.verify(token);
                if (b == false) {
                    throw new RuntimeException("token不存在或已失效，請重新獲取token");
                }
                return true;
            }
        }
        return false;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}

8、配置攔截器

package com.example.jwtdemo.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class InterceptorConfig implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(authenticationInterceptor())
                .addPathPatterns("/**");
    }
    @Bean
    public AuthenticationInterceptor authenticationInterceptor() {
        return new AuthenticationInterceptor();
    }
}

9、新建一個測試的控制器

package com.example.jwtdemo.controller;

import com.example.jwtdemo.common.JwtUtils;
import com.example.jwtdemo.config.LoginToken;
import com.example.jwtdemo.config.PassToken;
import org.springframework.web.bind.annotation.*;

@RestController
public class DemoController {
    @PassToken
    @PostMapping("getToken")
    public String getToken(@RequestParam String userName, @RequestParam String password){
        if(userName.equals("admin") && password.equals("123456")){
            String token = JwtUtils.sign("admin");
            return token;
        }
        return "用戶名或密碼錯誤";
    }

    @LoginToken
    @GetMapping("getData")
    public String getData() {
        return "獲取數據...";
    }

}