@WebFilter(filterName="MyFliter",urlPatterns="/api/share/*")
public class MyFliter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("filter 進入之前");
        filterChain.doFilter(servletRequest,servletResponse);
        System.out.println("filter 進入之后");
    }

    @Override
    public void destroy() {

    }
}

//在主程序處加上注解
//@ServletComponentScan("過濾器包名")

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud_nacos</artifactId>
        <groupId>com.csdn</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud_gateway</artifactId>
        <dependencies>
            <!--限流算法使用redis-->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-redis-reactive</artifactId>
            </dependency>
            <!--網(wǎng)關-->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-gateway</artifactId>
            </dependency>
            <!--服務注冊-->
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            </dependency>
            <dependency>
                <groupId>com.csdn</groupId>
                <artifactId>springcloud_common</artifactId>
                <version>${project.version}</version>
                <!--gateway 使用的是響應式的web編程模式  我們要把傳統(tǒng)的web編程模型刨除-->
                <exclusions>
                    <exclusion>
                        <groupId>org.springframework.boot</groupId>
                        <artifactId>spring-boot-starter-web</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
        </dependencies>

        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>

            </plugins>
        </build>
    </project>

server:
  port: 7000
spring:
  application:
    name: api-gateway
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 # 將gateway注冊到nacos
    gateway:
      discovery:
        locator:
          enabled: true # 讓gateway從nacos中獲取服務信息
      routes:
        - id: share-6002   # 只要唯一標識就行
          uri: lb://share-6002   #真是的地址
          order: 1
          predicates:      # 滿足斷言中的條件才理由
            - Path=/api/share/**,/admin/share/**
        - id: user-6001   # 只要唯一標識就行
          uri: lb://user-6001   #真是的地址
          order: 1
          predicates:      # 滿足斷言中的條件才理由
            - Path=/api/user/**,/admin/user/**

@SpringBootApplication
@EnableDiscoveryClient
public class GatewayApplication {
    public static void main(String[] args) {
        SpringApplication.run(GatewayApplication.class,args);
    }
}

package gateway.pradicate;

import com.alibaba.nacos.common.utils.StringUtils;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.cloud.gateway.handler.predicate.AbstractRoutePredicateFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;

import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;

@Component
public class AgeRoutePredicateFactory extends AbstractRoutePredicateFactory<AgeRoutePredicateFactory.Config> {

    // 1: 配置類,用于接收配置文件中的對應參數(shù)
    @Data
    @NoArgsConstructor
    public static class Config {
        private int minAge;//18 對應斷言配置中的第一個參數(shù)
        private int maxAge;//60 對應斷言配置中的第二個參數(shù)
    }
    // 2: 構造函數(shù)
    public AgeRoutePredicateFactory() {
        super(Config.class);
    }
    //3： 讀取配置文件的中參數(shù)值 給他賦值到配置類中的屬性上
    public List<String> shortcutFieldOrder() {
        //這個位置的順序必須跟配置文件中的值的順序對應
        return Arrays.asList("minAge", "maxAge");
    }
    //4： 斷言邏輯
    public Predicate<ServerWebExchange> apply(Config config) {
        return new Predicate<ServerWebExchange>() {
            @Override
            public boolean test(ServerWebExchange serverWebExchange) {
                // 4.1 接收前臺傳入的age參數(shù)
                String ageStr = serverWebExchange.getRequest().getQueryParams().getFirst("Age");

                //4.2 先判斷是否為空
                if (StringUtils.isNotEmpty(ageStr)) {
                    //3 如果不為空,再進行路由邏輯判斷
                    int age = Integer.parseInt(ageStr);
                    if (age < config.getMaxAge() && age > config.getMinAge()) {
                        return true;
                    } else {
                        return false;
                    }
                }
                return false;
            }
        };
    }
}

@Component
@Slf4j
public class LogGatewayFilterFactory
        extends AbstractGatewayFilterFactory<LogGatewayFilterFactory.Config> {

    //1： 配置類 接收配置參數(shù)
    @Data
    @NoArgsConstructor
    public static class Config {
        private boolean consoleLog;
    }
    
    //2： 構造函數(shù)【固定寫法】
    public LogGatewayFilterFactory() {
        super(Config.class);
    }

    //3： 讀取配置文件中的參數(shù) 賦值到 配置類中
    @Override
    public List<String> shortcutFieldOrder() {
        return Arrays.asList("consoleLog");
    }

    //4： 過濾器邏輯
    @Override
    public GatewayFilter apply(Config config) {
        return new GatewayFilter() {
            Long start = System.currentTimeMillis();
            @Override
            public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
                // 進入服務之前
                if (config.isConsoleLog()) {
                    log.info("{} 進入 {}",new Date(), exchange.getRequest().getPath());
                }
                // 調用服務 并且定義服務回來之后的邏輯
                // 注意 如果此時僅僅只是需要進入之前的驗證  不需要服務執(zhí)行完之后的邏輯 可以 return chain.filter(exchange)即可
                return chain.filter(exchange).then(Mono.fromRunnable(()->{
                    if (config.isConsoleLog()) {
                        Long end = System.currentTimeMillis();
                        log.info("{} 退出 {}. 共耗時：{}",new Date(), exchange.getRequest().getPath(),(end-start));
                    }
                }));

            }
        };
    }
}

//自定義全局過濾器需要實現(xiàn)GlobalFilter和Ordered接口														
												
@Component														
public class MyGloablFilter implements GlobalFilter, Ordered {														
														
    // 過濾邏輯														
    @Override														
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {														
														
        // 1 進入之前  controller														
        System.out.println("進入之前 在 MyGloablFilter");														
        // 2 放行														
        return chain.filter(exchange).then(Mono.fromRunnable(() -> {														
            // 在回調中寫 返回的邏輯  response														
            System.out.println("從controller 回來之后");														
        }));																								
        //3 回調																								
    }																									
    // 返回的數(shù)字越小 就越先起作用														
    @Override														
    public int getOrder() {														
        return 0;														
    }														
}