全局过滤器（GloabalFilter）

注意:

• 过滤器是指gateway在路由过程中（A地址路由到B地址）生效进行过滤操作的，所有首先你得先配一个地址路由。比如我站在这里设置将http://localhost:8000/gateway/* 请求路由到http://localhost:8010/user/*，那么下面的两个样例过滤器遍对这个过程进行过滤

        - id: user_route
          uri: lb://server-user
          #uri: http://localhost:8010
          predicates:
            - Path=/gateway/**
          filters:
            - RewritePath=/gateway/(?<segment>.*),/user/$\{segment}

• 开启gateway的日志，方便后面查看过程

logging:
  level:
    org.springframework.cloud.gateway: DEBUG

前置过滤器

@Component
public class MyHeadFilter implements GlobalFilter, Ordered {
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        System.out.println("123123");
        return chain.filter(exchange);
    }

    @Override
    public int getOrder() {
        return 0;
    }
}

后置过滤器

@Component
public class MyTailFilter implements GlobalFilter, Ordered {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        return chain.filter(exchange)
                .then(Mono.fromRunnable(
                        () -> System.out.println("abcabc")
                ));
    }
    @Override
    public int getOrder() {
        return 0;
    }
}

运行结果

然后访问http://localhost:8000/gateway/listAll，路由到http://localhost:8010/user/listAll成功
控制台输出

局部过滤器

有两种方式：

• 在上面全局模式的基础上，改为实现gatewayFilter和Ordered接口
• 继承AbstractGatewayFilterFactory类（推荐)

我这里就实现了一下第二种方法。参考自A博客和B博客

局部过滤器实现

public class MyPartGatewayFilterFactory extends AbstractGatewayFilterFactory<MyPartGatewayFilterFactory.Config> {

    private static final Log log = LogFactory.getLog(GatewayFilter.class);
    private static final String NAME = "name";

    public MyPartGatewayFilterFactory() {
        super(Config.class);
    }

    @Override
    public List<String> shortcutFieldOrder() {
        return Arrays.asList(NAME);
    }

    @Override
    public GatewayFilter apply(Config config) {
        return (exchange, chain) -> {
            return chain.filter(exchange).then(
                    Mono.fromRunnable(() -> {
                        StringBuilder sb = new StringBuilder("这是2022年7月25日8点半之后的请求，请求者name（入参）：");
                        sb.append(config.getName());
                        log.info(sb.toString());
                    })
            );
        };
    }
    public static class Config{
        private String name；
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
    }
}

在gateway的启动类上进行注册

@Bean
    public MyPartGatewayFilterFactory myGatewayFilterFactory(){
        return new MyPartGatewayFilterFactory();
    }

对应的配置文件部分

        - id: my_route
          uri: http://127.0.0.1:8010
          filters:
            - name: MyPart
              args:
                name: yuan
          predicates:
#            - After=2017-01-20T17:42:47.789-07:00[America/Denver]
            - After=2022-07-25T08:30:00.003+08:00[Asia/Shanghai]

运行结果

访问http://localhost:8000/user/test

• 8000是我的gateaway运行端口