當我們要把伺服器做成無狀態時（即伺服器端不會儲存session）,這裡我們就可以用到JWT。

為什麼使用JWT?

1.簡潔(Compact): 可以通過URL，POST引數或者在HTTP header傳送，因為資料量小，傳輸速度也很快。

2.自包含(Self-contained)：負載中包含了所有使用者所需要的資訊，避免了多次查詢資料庫。

3.安全(security): 與簡單的JSON相比，XML和XML數字簽名會引入複雜的安全漏洞。

認證原理

1.使用者登陸之後，使用密碼對賬號進行簽名生成並返回token並設定過期時間；

2.將token儲存到本地，並且每次傳送請求時都在header上攜帶token。

3.shiro過濾器攔截到請求並獲取header中的token，並提交到自定義realm的doGetAuthenticationInfo方法。

4.通過jwt解碼獲取token中的使用者名稱，從資料庫中查詢到密碼之後根據密碼生成jwt效驗器並對token進行驗證。

OK，介紹完後上程式碼。

JWT

引入pom

		<!--JWT-->
		<dependency>
			<groupId>com.auth0</groupId>
			<artifactId>java-jwt</artifactId>
			<version>3.4.0</version>
		</dependency>
 

首先我們需要自定義一個物件用來包裝token。

JwtToken

package com.style.orange.shiro;

import org.apache.shiro.authc.AuthenticationToken;

/**
 * @author Mr.Li
 * @create 2018-07-12 15:19
 * @desc
 **/
public class JwtToken implements AuthenticationToken {

    private String token;

    public JwtToken(String token) {
        this.token = token;
    }

    @Override
    public Object getPrincipal() {
        return token;
    }

    @Override
    public Object getCredentials() {
        return token;
    }
}
 

再寫一個工具類用來進行簽名和效驗Token

JwtToken

package com.style.orange.utils;

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

import java.util.Date;

/**
 * @author Mr.Li
 * @create 2018-07-12 14:23
 * @desc JWT工具類
 **/
public class JwtUtil {

    private static final long EXPIRE_TIME = 5 * 60 * 1000;

    /**
     * 校驗token是否正確
     *
     * @param token  金鑰
     * @param secret 使用者的密碼
     * @return 是否正確
     */
    public static boolean verify(String token, String username, String secret) {
        try {
            //根據密碼生成JWT效驗器
            Algorithm algorithm = Algorithm.HMAC256(secret);
            JWTVerifier verifier = JWT.require(algorithm)
                    .withClaim("username", username)
                    .build();
            //效驗TOKEN
            DecodedJWT jwt = verifier.verify(token);
            return true;
        } catch (Exception exception) {
            return false;
        }
    }

    /**
     * 獲得token中的資訊無需secret解密也能獲得
     *
     * @return token中包含的使用者名稱
     */
    public static String getUsername(String token) {
        try {
            DecodedJWT jwt = JWT.decode(token);
            return jwt.getClaim("username").asString();
        } catch (JWTDecodeException e) {
            return null;
        }
    }

    /**
     * 生成簽名,5min後過期
     *
     * @param username 使用者名稱
     * @param secret   使用者的密碼
     * @return 加密的token
     */
    public static String sign(String username, String secret) {
        Date date = new Date(System.currentTimeMillis() + EXPIRE_TIME);
        Algorithm algorithm = Algorithm.HMAC256(secret);
        // 附帶username資訊
        return JWT.create()
                .withClaim("username", username)
                .withExpiresAt(date)
                .sign(algorithm);

    }
}

前面認證原理說到我們要使用shiro來攔截token，那就需要我們自己寫一個jwt過濾器來作為shiro的過濾器。

JwtFilter

import com.style.orange.shiro.JwtToken;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author Mr.Li
 * @create 2018-07-12 15:56
 * @desc
 **/
public class JwtFilter extends BasicHttpAuthenticationFilter {


    /**
     * 執行登入認證
     *
     * @param request
     * @param response
     * @param mappedValue
     * @return
     */
    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
        try {
            executeLogin(request, response);
            return true;
        } catch (Exception e) {
            return false;
        }
    }

    /**
     *
     */
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String token = httpServletRequest.getHeader("Authorization");

        JwtToken jwtToken = new JwtToken(token);
        // 提交給realm進行登入，如果錯誤他會丟擲異常並被捕獲
        getSubject(request, response).login(jwtToken);
        // 如果沒有丟擲異常則代表登入成功，返回true
        return true;
    }



    /**
     * 對跨域提供支援
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域時會首先發送一個option請求，這裡我們給option請求直接返回正常狀態
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }
}

Shiro

引入pom

		<!--shiro-->
		<dependency>
			<groupId>org.apache.shiro</groupId>
			<artifactId>shiro-spring</artifactId>
			<version>1.4.0</version>
		</dependency>

準備自定義Realm

MyRealm

package com.style.orange.shiro;

import com.style.orange.model.SysUser;
import com.style.orange.service.SysUserService;
import com.style.orange.utils.JwtUtil;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authc.AuthenticationInfo;
import org.apache.shiro.authc.AuthenticationToken;
import org.apache.shiro.authc.SimpleAuthenticationInfo;
import org.apache.shiro.authz.AuthorizationInfo;
import org.apache.shiro.authz.SimpleAuthorizationInfo;
import org.apache.shiro.realm.AuthorizingRealm;
import org.apache.shiro.subject.PrincipalCollection;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

/**
 * @author Mr.Li
 * @create 2018-07-12 15:23
 * @desc
 **/
@Component
public class MyRealm extends AuthorizingRealm {

    @Autowired
    private SysUserService sysUserService;


    /**
     * 必須重寫此方法，不然Shiro會報錯
     */
    @Override
    public boolean supports(AuthenticationToken token) {
        return token instanceof JwtToken;
    }

    /**
     * 只有當需要檢測使用者許可權的時候才會呼叫此方法，例如checkRole,checkPermission之類的
     */
    @Override
    protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals) {
        String username = JwtUtil.getUsername(principals.toString());
        SysUser user = sysUserService.findByUserName(username);
        SimpleAuthorizationInfo simpleAuthorizationInfo = new SimpleAuthorizationInfo();
        return simpleAuthorizationInfo;
    }

    /**
     * 預設使用此方法進行使用者名稱正確與否驗證，錯誤丟擲異常即可。
     */
    @Override
    protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken auth) throws AuthenticationException {
        String token = (String) auth.getCredentials();
        // 解密獲得username，用於和資料庫進行對比
        String username = JwtUtil.getUsername(token);
        if (username == null) {
            throw new AuthenticationException("token無效");
        }

        SysUser userBean = sysUserService.findByUserName(username);
        if (userBean == null) {
            throw new AuthenticationException("使用者不存在!");
        }

        if (!JwtUtil.verify(token, username, userBean.getPassword())) {
            throw new AuthenticationException("使用者名稱或密碼錯誤");
        }

        return new SimpleAuthenticationInfo(token, token, "my_realm");
    }
}

ShiroConfig

package com.style.orange.shiro;

import com.style.orange.filter.JwtFilter;
import org.apache.shiro.mgt.DefaultSessionStorageEvaluator;
import org.apache.shiro.mgt.DefaultSubjectDAO;
import org.apache.shiro.mgt.SecurityManager;
import org.apache.shiro.spring.web.ShiroFilterFactoryBean;
import org.apache.shiro.web.mgt.DefaultWebSecurityManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.servlet.Filter;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * @author: PENG
 * @date: 2018/2/7
 * @description: shiro 配置類
 */

@Configuration
public class ShiroConfig {

    @Bean("shiroFilter")
    public ShiroFilterFactoryBean shiroFilter(SecurityManager securityManager) {
        ShiroFilterFactoryBean shiroFilterFactoryBean = new ShiroFilterFactoryBean();
        shiroFilterFactoryBean.setSecurityManager(securityManager);
        //攔截器
        Map<String, String> filterChainDefinitionMap = new LinkedHashMap<String, String>();
        // 配置不會被攔截的連結 順序判斷
        filterChainDefinitionMap.put("/login/**", "anon");
        filterChainDefinitionMap.put("/**.js", "anon");
        filterChainDefinitionMap.put("/druid/**", "anon");
        filterChainDefinitionMap.put("/swagger**/**", "anon");
        filterChainDefinitionMap.put("/webjars/**", "anon");
        filterChainDefinitionMap.put("/v2/**", "anon");
        // 新增自己的過濾器並且取名為jwt
        Map<String, Filter> filterMap = new HashMap<String, Filter>(1);
        filterMap.put("jwt", new JwtFilter());
        shiroFilterFactoryBean.setFilters(filterMap);
        //<!-- 過濾鏈定義，從上向下順序執行，一般將/**放在最為下邊
        filterChainDefinitionMap.put("/**", "jwt");


        //未授權介面;
        shiroFilterFactoryBean.setUnauthorizedUrl("/403");

        shiroFilterFactoryBean.setFilterChainDefinitionMap(filterChainDefinitionMap);

        return shiroFilterFactoryBean;
    }

    @Bean("securityManager")
    public SecurityManager securityManager(MyRealm myRealm) {
        DefaultWebSecurityManager securityManager = new DefaultWebSecurityManager();
        securityManager.setRealm(myRealm);

        /*
         * 關閉shiro自帶的session，詳情見文件
         * http://shiro.apache.org/session-management.html#SessionManagement-StatelessApplications%28Sessionless%29
         */
        DefaultSubjectDAO subjectDAO = new DefaultSubjectDAO();
        DefaultSessionStorageEvaluator defaultSessionStorageEvaluator = new DefaultSessionStorageEvaluator();
        defaultSessionStorageEvaluator.setSessionStorageEnabled(false);
        subjectDAO.setSessionStorageEvaluator(defaultSessionStorageEvaluator);
        securityManager.setSubjectDAO(subjectDAO);

        return securityManager;
    }
}

OK，接下來我們進行測試，我這裡集成了swagger2,測試起來比較方便。

如圖紅色標註就是返回的token，之後我把token放到請求的header中訪問就可以了通過了。