工具类：

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5Util {
    private static final char[] MD5_HEX_DIGITS = new char[]{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};

    public MD5Util() {
    }

    public static String encryptionMD5(String content) throws NoSuchAlgorithmException {
        byte[] strTemp = content.toString().getBytes();
        MessageDigest mdTemp = MessageDigest.getInstance("MD5");
        mdTemp.update(strTemp);
        byte[] md = mdTemp.digest();
        int j = md.length;
        char[] str = new char[j * 2];
        int k = 0;

        for(int i = 0; i < j; ++i) {
            byte b = md[i];
            str[k++] = MD5_HEX_DIGITS[b >> 4 & 15];
            str[k++] = MD5_HEX_DIGITS[b & 15];
        }

        return new String(str);
    }

    public static String encryptionMD5(String content, String charset) throws NoSuchAlgorithmException, UnsupportedEncodingException {
        byte[] strTemp = content.toString().getBytes(charset);
        MessageDigest mdTemp = MessageDigest.getInstance("MD5");
        mdTemp.update(strTemp);
        byte[] md = mdTemp.digest();
        int j = md.length;
        char[] str = new char[j * 2];
        int k = 0;

        for(int i = 0; i < j; ++i) {
            byte b = md[i];
            str[k++] = MD5_HEX_DIGITS[b >> 4 & 15];
            str[k++] = MD5_HEX_DIGITS[b & 15];
        }

        return new String(str);
    }

    public static void main(String[] args) throws NoSuchAlgorithmException {
        System.out.println(encryptionMD5("4ikmlp"));
    }
}

tokenUtil

import com.yuelvhui.util.exception.ServiceException;
import com.yuelvhui.util.safety.MD5Util;
import com.yuelvhui.util.string.StringUtil;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class TokenUtil {

    public static boolean verifyToken(String managerId, String timeStamp, String mchKey, String token) {
        String preSignStr = StringUtil.append(managerId, ".", timeStamp, ".", mchKey);
        if (MD5Sign(preSignStr, token)) {
            return true;
        }
        throw new ServiceException(ErrorCode.TokenVerificationFailure.getCode(), "请求头签名校验失败");
    }

    public static boolean MD5Sign(String str, String sign) {
        try {
            String sign2 = MD5Util.encryptionMD5(str);
            System.out.println("系统加密数据"+"-----"+sign2);
            System.out.println("传值加密数据"+"-----"+sign);
            if (sign2.equals(sign)) {
                return true;
            }
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return false;
    }

    public static String encryptionMD5(String content) throws NoSuchAlgorithmException {
        byte[] strTemp = content.toString().getBytes();
        MessageDigest mdTemp = MessageDigest.getInstance("MD5");
        mdTemp.update(strTemp);
        byte[] md = mdTemp.digest();
        int j = md.length;
        char[] str = new char[j * 2];
        int k = 0;

        for(int i = 0; i < j; ++i) {
            byte b = md[i];
            str[k++] = MD5_HEX_DIGITS[b >> 4 & 15];
            str[k++] = MD5_HEX_DIGITS[b & 15];
        }

        return new String(str);
    }
}

注解类：

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 SystemToken {

    boolean required() default true;
}

拦截器：

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.yuelvhui.entity.PermissionMerchant;
import com.yuelvhui.interfaces.SystemToken;
import com.yuelvhui.mapper.PermissionMerchantMapper;
import com.yuelvhui.util.exception.ServiceException;
import com.yuelvhui.util.string.StringUtil;
import com.yuelvhui.utils.Constants;
import com.yuelvhui.utils.ErrorCode;
import com.yuelvhui.utils.TokenUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.ObjectUtils;
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 {

    @Autowired
    PermissionMerchantMapper permissionMerchantMapper;

    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object object) throws Exception {
        // 从 http 请求头中取出 token
        String token = httpServletRequest.getHeader(Constants.HTTP_HEADER_AUTHORIZATION);
        // 如果不是映射到方法直接通过
        if (!(object instanceof HandlerMethod)) {
            return true;
        }
        HandlerMethod handlerMethod = (HandlerMethod) object;
        Method method = handlerMethod.getMethod();
        //检查有没有需要用户权限的注解
        if (method.isAnnotationPresent(SystemToken.class)) {
            SystemToken systemToken = method.getAnnotation(SystemToken.class);
            if (systemToken.required()) {
                // 执行认证
                if (StringUtil.isBlank(token) || !token.startsWith(Constants.AUTHORIZATION_PREFIX_SYS)) {
                    throw new ServiceException(ErrorCode.TokenVerificationFailure.getCode(), "无请求头或请求头签名校验失败");
                }
                //截取到用户的token
                token = token.substring(Constants.AUTHORIZATION_PREFIX_SYS.length()).toLowerCase();
                try {
                    String[] params = token.split("\\.");
                    PermissionMerchant merchant = permissionMerchantMapper.selectOne(new LambdaQueryWrapper<PermissionMerchant>().eq(PermissionMerchant::getMchId, params[0]));
                    System.out.println("密钥"+"-----"+merchant.getMchKey());
                    if (ObjectUtils.isEmpty(merchant)) {
                        throw new ServiceException(ErrorCode.NotFoundData.getCode(), "Token校验失败");
                    }
                    //校验签名
                    return TokenUtil.verifyToken(params[0], params[1], merchant.getMchKey(), params[2]);
                }catch (Exception e){
                    throw new ServiceException(ErrorCode.TokenVerificationFailure.getCode(),"Token信息验证失败");
                }
            }
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest,
                           HttpServletResponse httpServletResponse,
                           Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest,
                                HttpServletResponse httpServletResponse,
                                Object o, Exception e) throws Exception {
    }