Spring Boot 3 中 WebFilter 的执行顺序流程分析

import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Mono;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;
@Component
@Order(1) // 明确指定顺序值为1（高优先级）
public class FilterA implements WebFilter {
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
        System.out.println("FilterA (Order=1) - Before Logic"); // 在执行业务逻辑前
        return chain.filter(exchange) // 将请求传递到链中的下一个过滤器或处理器
                   .then(Mono.fromRunnable(() -> 
                          System.out.println("FilterA (Order=1) - After Logic"))); // 在业务逻辑执行后和响应发送前
    }
}

import org.springframework.core.Ordered;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Mono;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;
@Component
public class FilterB implements WebFilter, Ordered { // 同时实现WebFilter和Ordered接口
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
        System.out.println("FilterB (Order=2) - Before Logic");
        return chain.filter(exchange)
                   .then(Mono.fromRunnable(() -> 
                          System.out.println("FilterB (Order=2) - After Logic")));
    }
    @Override
    public int getOrder() { // 实现Ordered接口要求的方法，返回定义的顺序值
        return 2; // 显式定义顺序值为2
    }
}

FilterA (Order=1) - Before Logic  // 最高优先级(1)最先处理请求
FilterB (Order=2) - Before Logic  // 次高优先级(2)接着处理请求
... (执行业务控制器逻辑) ...          // 实际业务处理
FilterB (Order=2) - After Logic   // 次高优先级(2)最先处理响应（反向）
FilterA (Order=1) - After Logic   // 最高优先级(1)最后处理响应（反向）