SSM基于Token的登录认证

1、什么是token

token的意思是“令牌”，是服务端生成的一串字符串，作为客户端进行请求的一个标识。

当用户第一次登录后，服务器生成一个token并将此token返回给客户端，以后客户端只需带上这个token前来请求数据即可，无需再次带上用户名和密码。

简单token的组成；uid(用户唯一的身份标识)、time(当前时间的时间戳)、sign（签名，token的前几位以哈希算法压缩成的一定长度的十六进制字符串。为防止token泄露）

2、SSM基于XML配置

pom.xml引入

        <!-- token -->
       <dependency>
        <groupId>com.auth0</groupId>
        <artifactId>java-jwt</artifactId>
        <version>2.2.0</version>
       </dependency>
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt</artifactId>
            <version>0.9.0</version>
        </dependency>

spring-mvc.xml

配置拦截器

<mvc:interceptors>
        <!-- 使用bean定义一个Interceptor，直接定义在mvc:interceptors根下面的Interceptor将拦截所有的请求 -->
        <!-- <bean class="com.bybo.aca.web.interceptor.Login"/> -->
        <mvc:interceptor>
            <!-- 进行拦截：/**表示拦截所有controller -->
            <mvc:mapping path="/**" />
            <!-- 不进行拦截 -->
            <mvc:exclude-mapping path="/user/login"/>
             <!-- 不进行拦截 -->
            <mvc:exclude-mapping path="/get/tableInforAllByStatus" />
            <bean class="com.baccarat.util.JWTInterceptor" />
        </mvc:interceptor>
    </mvc:interceptors>

拦截器实体类

package com.baccarat.util;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

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

import org.apache.log4j.Logger;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import com.baccarat.controller.UserController;
import com.baccarat.entity.User;

@Component
public class JWTInterceptor implements HandlerInterceptor{
    public static Logger logger = Logger.getLogger(UserController.class);

    public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
            throws Exception {
        // TODO Auto-generated method stub

    }

    public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
            throws Exception {
        // TODO Auto-generated method stub

    }

    /**
     * Token validates the interceptor
     * @author Stephen
     * @time 2019-10-11 17:00:32
     * */
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object arg2) throws IOException {
        ResultVO result = new ResultVO();
        PrintWriter out = null ;
        String token = request.getHeader("token");
        String userId = request.getHeader("userId");
        /** 您的处理逻辑 */

        //以下是返回拦截器拦截后返回json格式的方式
        result.setStatus(203);
        result.setMessage("Login verification failed, please login again");
        String jsonStr = BaccaratUtil.toJSon(result);

        response.setCharacterEncoding("UTF-8");
        response.setContentType("application/json; charset=utf-8");

        out = response.getWriter();
        out.append(jsonStr);
        return false;
    }

}

JWTUtil.java

package com.baccarat.util;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.apache.log4j.Logger;

import com.auth0.jwt.JWTSigner;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.internal.com.fasterxml.jackson.databind.ObjectMapper;
import com.baccarat.controller.UserController;
import com.baccarat.entity.User;

/**
 * @Todo JWT(json web token),util
 * @author Stephen
 * @Time 2019-10-11 12:12:04
 */
public class JWTUtil {

    private static Logger logger = Logger.getLogger(UserController.class);

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

    private static final String EXP = "exp";

    private static final String PAYLOAD = "payload";

    private static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    /**
     * @Todo Encrypt, passing in an object and expiration date
     * @author Stephen
     * @Time 2019-10-11 12:12:44
     */
    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);
            return signer.sign(claims);
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * @Todo Decrypt, passing in an encrypted token string and decrypted type
     * @author Stephen
     * @Time 2019-10-11 12:13:08
     * @param jwt，classT
     * @return T
     */
    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);
                }
            }
            return null;
        } catch (Exception e) {
            return null;
        }
    }

}

如有疑问请留意