return super.writeWith(fluxBody.map(dataBuffer -> {
	
 
	byte[] content = new byte[dataBuffer.readableByteCount()];
	
	dataBuffer.read(content);
	// 釋放掉內存
	DataBufferUtils.release(dataBuffer);
	String str = new String(content, Charset.forName("UTF-8"));
 
	originalResponse.getHeaders().setContentLength(str.getBytes().length);
	log.error("gateway catch service exception error:"+ str);
	
	JsonResult result = new JsonResult();
	result.setCode(ErrorCode.SYS_EXCEPTION.getCode());
	result.setMessage(ErrorCode.SYS_EXCEPTION.getMsg());
	
	return bufferFactory.wrap(str.getBytes());
}));                   

DataBufferFactory dataBufferFactory = new DefaultDataBufferFactory();

package com.server.gateway.filters;
 
import java.nio.charset.Charset;
import java.util.concurrent.atomic.AtomicReference;
 
import org.apache.http.protocol.HTTP;
import org.reactivestreams.Publisher;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.core.io.buffer.DefaultDataBufferFactory;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.http.server.reactive.ServerHttpResponseDecorator;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
 
import com.framework.common.enums.ErrorCode;
import com.framework.common.web.JsonResult;
 
import lombok.extern.slf4j.Slf4j;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
 
@Component
@Slf4j
public class WrapperResponseGlobalFilter implements GlobalFilter, Ordered{
 
	@Override
	public int getOrder() {
		// -1 is response write filter, must be called before that
		return -2;
	}
 
	@Override
	public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
		ServerHttpResponse originalResponse = exchange.getResponse();
		DataBufferFactory bufferFactory = originalResponse.bufferFactory();
		ServerHttpResponseDecorator decoratedResponse = new ServerHttpResponseDecorator(originalResponse) {
			@Override
			public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
				AtomicReference<String> bodyRef = new AtomicReference<>();
				if (body instanceof Flux) {
					Flux<? extends DataBuffer> fluxBody = (Flux<? extends DataBuffer>) body;
					
					return super.writeWith(fluxBody.buffer().map(dataBuffers -> {
						
						DataBufferFactory dataBufferFactory = new DefaultDataBufferFactory();
						DataBuffer join = dataBufferFactory.join(dataBuffers);
						
						byte[] content = new byte[join.readableByteCount()];
						
						join.read(content);
						// 釋放掉內存
						DataBufferUtils.release(join);
						String str = new String(content, Charset.forName("UTF-8"));
		
						originalResponse.getHeaders().setContentLength(str.getBytes().length);
						log.error("gateway catch service exception error:"+ str);
						
						JsonResult result = new JsonResult();
				        result.setCode(ErrorCode.SYS_EXCEPTION.getCode());
				        result.setMessage(ErrorCode.SYS_EXCEPTION.getMsg());
				        
						return bufferFactory.wrap(str.getBytes());
					}));
					
				}
				// if body is not a flux. never got there.
	                return super.writeWith(body);
	            }
	        };
	        // replace response with decorator
	        return chain.filter(exchange.mutate().response(decoratedResponse).build());
	    }
 
}