SpringCloud-gateway全局GlobalFilter获取post的请求参数

gateway里面可以自定义普通filter，也可以创建自定义的GlobalFilter。

GlobalFilter实际上还是比较常用的，譬如可以在GlobalFilter里做日志处理、认证鉴权等，这里就涉及一个获取到请求参数的问题。

用户发起Get、Post请求，经过网关gateway，gateway的GlobalFilter进行拦截——获取参数——处理并包装——转到下一级，我们就来看看该怎么获取请求的参数。

<parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.0.6.RELEASE</version><relativePath/> <!-- lookup parent from repository --></parent><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><java.version>1.8</java.version><spring-cloud.version>Finchley.SR1</spring-cloud.version></properties>

Get请求

/*** @author wuweifeng wrote on 2018/10/24.*/
@Component
public class AuthSignFilter implements GlobalFilter, Ordered {@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {String token = exchange.getRequest().getQueryParams().getFirst("authToken");if (token == null || token.isEmpty()) {exchange.getResponse().setStatusCode(HttpStatus.UNAUTHORIZED);return exchange.getResponse().setComplete();}return chain.filter(exchange);}@Overridepublic int getOrder() {return 0;}
}

这里定义了一个GlobalFilter，如果是Get请求，就可以通过getQueryParams().getFirst("你的key")的方式来获取。

可以看到已经获取到了Get请求的参数，如果有多个请求参数，就可以通过遍历exchange.getRequest().getQueryParams()来获取。

Post请求

post请求的传参获取相对比较麻烦一些，gateway采用了webflux的方式来封装的请求体。

我们知道post常用的两种传参content-type是application/x-www-form-urlencoded和application/json，这两种方式还是有区别的。

下面来看一下获取Post请求体的方法，关于webflux获取内容的教程请看上一篇。

package com.example.gateway.filter;import io.netty.buffer.ByteBufAllocator;
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.DataBufferUtils;
import org.springframework.core.io.buffer.NettyDataBufferFactory;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;import java.net.URI;
import java.nio.CharBuffer;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import java.util.concurrent.atomic.AtomicReference;/*** @author wuweifeng wrote on 2018/10/24.*/
@Component
public class AuthSignFilter implements GlobalFilter, Ordered {@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {ServerHttpRequest serverHttpRequest = exchange.getRequest();String method = serverHttpRequest.getMethodValue();if ("POST".equals(method)) {//从请求里获取Post请求体String bodyStr = resolveBodyFromRequest(serverHttpRequest);//TODO 得到Post请求的请求参数后，做你想做的事//下面的将请求体再次封装写回到request里，传到下一级，否则，由于请求体已被消费，后续的服务将取不到值URI uri = serverHttpRequest.getURI();ServerHttpRequest request = serverHttpRequest.mutate().uri(uri).build();DataBuffer bodyDataBuffer = stringBuffer(bodyStr);Flux<DataBuffer> bodyFlux = Flux.just(bodyDataBuffer);request = new ServerHttpRequestDecorator(request) {@Overridepublic Flux<DataBuffer> getBody() {return bodyFlux;}};//封装request，传给下一级return chain.filter(exchange.mutate().request(request).build());} else if ("GET".equals(method)) {Map requestQueryParams = serverHttpRequest.getQueryParams();//TODO 得到Get请求的请求参数后，做你想做的事return chain.filter(exchange);}return chain.filter(exchange);}/*** 从Flux<DataBuffer>中获取字符串的方法* @return 请求体*/private String resolveBodyFromRequest(ServerHttpRequest serverHttpRequest) {//获取请求体Flux<DataBuffer> body = serverHttpRequest.getBody();AtomicReference<String> bodyRef = new AtomicReference<>();body.subscribe(buffer -> {CharBuffer charBuffer = StandardCharsets.UTF_8.decode(buffer.asByteBuffer());DataBufferUtils.release(buffer);bodyRef.set(charBuffer.toString());});//获取request bodyreturn bodyRef.get();}private DataBuffer stringBuffer(String value) {byte[] bytes = value.getBytes(StandardCharsets.UTF_8);NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory(ByteBufAllocator.DEFAULT);DataBuffer buffer = nettyDataBufferFactory.allocateBuffer(bytes.length);buffer.write(bytes);return buffer;}@Overridepublic int getOrder() {return 0;}
}

这里有详细的获取Post请求体的方法，无论是application/x-www-form-urlencoded和application/json都可以通过上面的方式。

看结果：

下面是@RequestBody形式的

这是后端消费的服务代码

也能正常接收@RequestBody请求并解析。