【深入解析spring cloud gateway】11 用最简单的方式修改gateway响应报文

在Spring Cloud Gateway中，修改响应体可以通过定义一个全局的过滤器来实现。以下是一个简单的示例，展示了如何创建一个自定义的全局过滤器来修改响应体：

import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
 
import java.nio.charset.StandardCharsets;
 
@Component
public class ModifyResponseGlobalFilter implements GlobalFilter {
 
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpResponse originalResponse = exchange.getResponse();
        
        // 包装响应对象
        DataBufferFactory bufferFactory = originalResponse.bufferFactory();
        ServerHttpResponseDecorator decoratedResponse = new ServerHttpResponseDecorator(originalResponse) {
            @Override
            public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
                if (body instanceof Flux) {
                    Flux<? extends DataBuffer> fluxBody = (Flux<? extends DataBuffer>) body;
                    
                    return super.writeWith(fluxBody.map(dataBuffer -> {
                        // 这里可以修改响应体数据
                        byte[] content = new byte[dataBuffer.readableByteCount()];
                        dataBuffer.read(content);
                        DataBufferUtils.release(dataBuffer);
                        
                        // 将修改后的数据放入新的数据缓冲区
                        return bufferFactory.wrap(new String(content, StandardCharsets.UTF_8).replace("Hello", "Modified").getBytes());
                    }));
                }
                
                return super.writeWith(body);
            }
        };
 
        // 将修改后的响应对象放回exchange
        return chain.filter(exchange.mutate().response(decoratedResponse).build());
    }
}

在这个例子中，我们创建了一个名