[Spring Cloud] gateway全局异常捕捉统一返回值

在Spring Cloud Gateway中，可以通过定义一个全局过滤器来捕捉异常，并返回统一的响应格式。以下是一个简单的实现示例：

import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.core.io.buffer.NettyDataBufferFactory;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
 
import java.nio.charset.StandardCharsets;
 
public class GlobalExceptionHandlerFilter implements GlobalFilter {
 
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        return chain.filter(exchange).onErrorResume((throwable) -> {
            ServerHttpResponse response = exchange.getResponse();
            // 设置响应状态码
            response.setStatusCode(HttpStatus.INTERNAL_SERVER_ERROR);
            // 设置响应头
            response.getHeaders().set("Content-Type", "application/json");
 
            // 创建返回的统一结果对象
            String errorResult = "{\"code\": 500, \"message\": \"系统异常，请联系管理员\"}";
            // 返回统一结果
            DataBufferUtils.write(response.bufferFactory(), errorResult, new NettyDataBufferFactory(ByteBufAllocator.DEFAULT))
                    .doOnError(err -> DataBufferUtils.release(response.getBody()))
                    .doOnTerminate(() -> response.close());
 
            return Mono.empty();
        });
    }
}

然后需要将这个全局过滤器注册到Spring Cloud Gateway中：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
@Configuration
public class GatewayConfig {
 
    @Bean
    public GlobalExceptionHandlerFilter globalExceptionHandlerFilter() {
        return new GlobalExceptionHandlerFilter();
    }
}

这样配置后，当GatewayFilterChain中的过滤器链发生异常时，GlobalExceptionHandlerFilter将会捕捉到异常，并返回统一的JSON格式的错误信息。