Gateway集成方法以及拦截器和过滤器的使用

前提：请先创建好一个SpringBoot项目 

1. 引入依赖

 SpringCloud 和 alibabaCloud 、 SpringBoot间对版本有强制要求，我使用的springboot是3.0.2的版本。版本对应关系请看：版本说明 · alibaba/spring-cloud-alibaba Wiki · GitHub

    <dependencyManagement><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-dependencies</artifactId><version>2022.0.3</version></dependency></dependencyManagement><dependencies><!-- SpringCloud组件之一，不加会提示错误 --><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-loadbalancer</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-bootstrap</artifactId><version>3.1.4</version></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-gateway</artifactId></dependency><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId></dependency><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId></dependency></dependencies>

2. 搭建网关

配置bootstrap.yml文件：

server:port: 8083
spring:application:name: big-news-admin-gatewaycloud:nacos:discovery:server-addr: 你的ip:8848config:server-addr: 你的ip:8848file-extension: yml

 Nacos配置中心：

yml示例：

spring:data:redis:host: localhostport: 6379cloud:gateway:globalcors:add-to-simple-url-handler-mapping: truecorsConfigurations:'[/**]':allowedHeaders: "*"allowedOrigins: "*"allowedMethods:- GET- POST- DELETE- PUT- OPTIONroutes:# 平台管理- id: useruri: lb://big-news-userpredicates:- Path=/user/**# 分类- id: categoryuri: lb://big-news-categorypredicates:- Path=/category/**# 文章- id: articleuri: lb://big-news-articlepredicates:- Path=/article/**# 文件- id: commonuri: lb://big-news-commonpredicates:- Path=/upload/**
token:secretKey: rikka7e7f74ef-62b5-4b29-96ae-c698f7c823c1expirationTime: 1080000060

解释：

该配置用于解决跨域问题

路由断言规则，id需唯一，uri中的名称需要对应服务的应用名。path用于匹配路由。

以下图举例：uri意味着将请求匹配到nacos中名叫big-news-user的服务，path意味着根据只要请求携带`user`就匹配服务。

可用 filters 过滤掉请求中的字段，比如下图。意味着最后到服务的实际请求不会携带`user`，你就不需要在controller的接收路径上上写`user`。

 3. 全局过滤器实现jwt校验

思路分析：

1. 用户进入网关开始登陆，网关过滤器进行判断，如果是登录，则路由到后台管理微服务进行登录

2. 用户登录成功，后台管理微服务签发JWT TOKEN信息返回给用户

3. 用户再次进入网关开始访问，网关过滤器接收用户携带的TOKEN

4. 网关过滤器解析TOKEN ，判断是否有权限，如果有，则放行，如果没有则返回未认证错误  

 3.1 拷贝一份jwt工具类到网关服务

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.security.Keys;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;import javax.crypto.SecretKey;
import java.nio.charset.StandardCharsets;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;@Component
public class JwtUtil {private static final String USER_CLAIMS_KEY = "user";// 过期时间@Value("${token.expirationTime}")private long EXPIRE_TIME;// 密钥@Value("${token.secretKey}")private String SECRET;/*** 创建JWT Token** @param payload 载荷（Claims）* @return JWT Token*/public String createToken(Map<String, Object> payload) {// 1. 创建一个密钥SecretKey key = Keys.hmacShaKeyFor(SECRET.getBytes(StandardCharsets.UTF_8));// 2. 创建JWT Builder// 注意：这里的签名算法不能是 RS256，需要使用 HS256io.jsonwebtoken.JwtBuilder builder = Jwts.builder().setClaims(payload).setExpiration(new Date(System.currentTimeMillis() + EXPIRE_TIME)).signWith(key, SignatureAlgorithm.HS256);// 3. 生成JWT Tokenreturn builder.compact();}/*** 解析JWT Token** @param token JWT Token* @return 载荷（Claims）*/public Map<String, Object> parseToken(String token) {// 1. 获取密钥SecretKey key = Keys.hmacShaKeyFor(SECRET.getBytes(StandardCharsets.UTF_8));// 2. 解析JWT TokenClaims claims = Jwts.parser().setSigningKey(key).build().parseClaimsJws(token).getBody();// 3. 将Claims里的内容转换成MapMap<String, Object> payload = new HashMap<>(claims);payload.remove("exp");payload.remove("iat");payload.remove("iss");payload.remove("aud");payload.remove("nbf");payload.remove("sub");payload.remove("jti");return payload;}/*** 获取JWT Token的过期时间** @param token JWT Token* @return 过期时间*/public Date getExpirationDateFromToken(String token) {Claims claims = parseClaims(token);if (claims != null) {return claims.getExpiration();}return null;}/*** 验证JWT Token是否有效** @param token JWT Token* @return 是否有效*/public boolean validateToken(String token) {try {parseClaims(token);return true;} catch (Exception e) {return false;}}/*** 获取payload中的用户信息** @param token JWT Token* @return 用户信息*/public Map<String, Object> getUserFromToken(String token) {Map<String, Object> user = null;Claims claims = parseClaims(token);if (claims != null) {user = (Map<String, Object>) claims.get(USER_CLAIMS_KEY);}return user;}/*** 解析JWT Token中的Claims** @param token JWT Token* @return Claims*/public Claims parseClaims(String token) {try {SecretKey key = Keys.hmacShaKeyFor(SECRET.getBytes(StandardCharsets.UTF_8));return Jwts.parser().setSigningKey(key).build().parseClaimsJws(token).getBody();} catch (Exception e) {return null;}}}

 3.2 网关微服务中新建全局过滤器

import cn.hutool.json.JSONUtil;
import com.alibaba.cloud.commons.lang.StringUtils;
import com.xin.common.properties.TokenProperties;
import com.xin.common.utils.JwtUtil;
import io.jsonwebtoken.Claims;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;import java.util.Objects;@Component
public class AuthorizeFilter implements Ordered, GlobalFilter {@Autowiredprivate StringRedisTemplate stringRedisTemplate;//用于接收token的信息，你可按实际请看书写，也可以直接在这个类里定义静态参数。//tokenProperties主要包含：密钥key、过期时间@Autowiredprivate TokenProperties tokenProperties;@Autowiredprivate JwtUtil jwtUtil;@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {//1.获取请求ServerHttpRequest request = exchange.getRequest();ServerHttpResponse response = exchange.getResponse();//2.判断是否是登录操作if (request.getURI().getPath().contains("/login")) {//放行return chain.filter(exchange);}String token = request.getHeaders().getFirst("Authorization");//3.若token为空，校验失败if (StringUtils.isEmpty(token)){response.setStatusCode(HttpStatus.UNAUTHORIZED);//结束请求return response.setComplete();}try {//4. 解析tokenClaims claims = jwtUtil.parseClaims(token);//获得token解析后中的用户信息Object o = claims.get("user");String user = JSONUtil.toJsonStr(o);String id = user.substring(user.indexOf(":")+1, user.indexOf(","));//5.判断token是否在redis中过期，或删除String object = stringRedisTemplate.opsForValue().get("token:" + id + ":" + token);if (Objects.isNull(object)) {response.setStatusCode(HttpStatus.UNAUTHORIZED);//结束请求return response.setComplete();}// 将用户信息存放进 header中ServerHttpRequest serverHttpRequest = request.mutate().headers(httpHeaders -> {httpHeaders.add("user", user + "");}).build();exchange.mutate().request(serverHttpRequest).build();}catch (Exception e){e.printStackTrace();response.setStatusCode(HttpStatus.UNAUTHORIZED);return response.setComplete();}//5.放行return chain.filter(exchange);}/*** 优先级设置，值越小 优先级越高* @return*/@Overridepublic int getOrder() {return 0;}
}

注意，该过滤器只是实现了对Token的校验，并将解析结果存放进header进一步转发。获取user信息，还需在实际的服务里定义拦截器获取：

@Component
@Slf4j
public class LoginInterceptor implements HandlerInterceptor {@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {String userString = request.getHeader("user");Optional<String> optional = Optional.ofNullable(userString);if(optional.isPresent()) {//把用户存入threadLocal中TreadLocalUtil.setUser(userString);log.info("设置用户信息到threadlocal中...");}return true;}@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {TreadLocalUtil.clear();log.info("清理threadlocal...");}
}

 在WebMvcConfig中配置该拦截器：

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 WebMvcConfig implements WebMvcConfigurer {@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(new LoginInterceptor()).addPathPatterns("/**");}
}

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