这篇文章主要介绍了SpringCloud Gateway自定义filter获取body中的数据为空,本文给大家介绍的非常详细，对大家的学习或工作具有一定的参考借鉴价值，需要的朋友可以参考下
最近在使用SpringCloud Gateway进行网关的开发，我使用的版本是：SpringBoot的2.3.4.RELEASE+SpringCloud的Hoxton.SR8，在自定义过滤器时需要获取ServerHttpRequest中body的数据，发现一直无法获取到数据，经过各种百度、谷歌，再加上自己的实践，终于找到解决方案：
1、首先创建一个全局过滤器把body中的数据缓存起来
package com.cloudpath.gateway.portal.filter; import lombok.extern.slf4j.Slf4j; 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.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; /** * @author mazhen * @className CacheBodyGlobalFilter * @Description 把body中的数据缓存起来 * @date 2020/10/28 18:02 */ @Slf4j @Component public class CacheBodyGlobalFilter implements Ordered, GlobalFilter { // public static final String CACHE_REQUEST_BODY_OBJECT_KEY = "cachedRequestBodyObject"; @Override public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) { if (exchange.getRequest().getHeaders().getContentType() == null) { return chain.filter(exchange); } else { return DataBufferUtils.join(exchange.getRequest().getBody()) .flatMap(dataBuffer -> { DataBufferUtils.retain(dataBuffer); Flux cachedFlux = Flux .defer(() -> Flux.just(dataBuffer.slice(0, dataBuffer.readableByteCount()))); ServerHttpRequest mutatedRequest = new ServerHttpRequestDecorator( exchange.getRequest()) { @Override public Flux getBody() { return cachedFlux; } }; //exchange.getAttributes().put(CACHE_REQUEST_BODY_OBJECT_KEY, cachedFlux); return chain.filter(exchange.mutate().request(mutatedRequest).build()); }); } } @Override public int getorder() { return Ordered.HIGHEST_PRECEDENCE; } }
CacheBodyGlobalFilter这个全局过滤器的目的就是把原有的request请求中的body内容读出来，并且使用ServerHttpRequestDecorator这个请求装饰器对request进行包装，重写getBody方法，并把包装后的请求放到过滤器链中传递下去。这样后面的过滤器中再使用exchange.getRequest().getBody()来获取body时，实际上就是调用的重载后的getBody方法，获取的最先已经缓存了的body数据。这样就能够实现body的多次读取了。
值得一提的是，这个过滤器的order设置的是Ordered.HIGHEST_PRECEDENCE，即最高优先级的过滤器。优先级设置这么高的原因是某些系统内置的过滤器可能也会去读body，这样就会导致我们自定义过滤器中获取body的时候报body只能读取一次这样的错误如下:
java.lang.IllegalStateException: Only one connection receive subscriber allowed. at reactor.ipc.netty.channel.FluxReceive.startReceiver(FluxReceive.java:279) at reactor.ipc.netty.channel.FluxReceive.lambda$subscribe$2(FluxReceive.java:129) at
所以，必须把CacheBodyGlobalFilter的优先级设到最高。
package com.cloudpath.iam.gateway.customerfilter; import com.cloudpath.iam.gateway.utils.FilterRequestResponseUtil; import lombok.extern.slf4j.Slf4j; import org.springframework.cloud.gateway.filter.GatewayFilter; import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory; import org.springframework.core.io.buffer.DataBuffer; import org.springframework.http.server.reactive.ServerHttpRequest; import org.springframework.stereotype.Component; import reactor.core.publisher.Flux; import java.util.Arrays; import java.util.List; /** * @author by mazhen * @Classname TestGatewayFilterFactory * @Description 自定义过滤器获取body中的数据 * @Date 2020/10/27 14:38 */ @Component @Slf4j public class TestGatewayFilterFactory extends AbstractGatewayFilterFactory { @Override public List shortcutFieldOrder() { return Arrays.asList("enabled"); } public TestGatewayFilterFactory() { super(Config.class); log.info("Loaded TestGatewayFilterFactory"); } @Override public GatewayFilter apply(Config config) { return (exchange, chain) -> { if (!config.isEnabled()) { return chain.filter(exchange); } if (null != exchange) { ServerHttpRequest httpRequest = exchange.getRequest(); try { Flux dataBufferFlux = httpRequest.getBody(); //获取body中的数据 String body = FilterRequestResponseUtil.resolveBodyFromrequest(dataBufferFlux); log.info("body:{}",body); } catch (Exception e) { log.error("异常:",e); return chain.filter(exchange); } } return chain.filter(exchange); }; } public static class Config { /** * 控制是否开启统计 */ private boolean enabled; public Config() { } public boolean isEnabled() { return enabled; } public void setEnabled(boolean enabled) { this.enabled = enabled; } } }
3、解析body的工具类
package com.cloudpath.iam.gateway.utils; import org.springframework.core.io.buffer.DataBuffer; import org.springframework.core.io.buffer.DataBufferUtils; import reactor.core.publisher.Flux; import java.nio.CharBuffer; import java.nio.charset.StandardCharsets; import java.util.concurrent.atomic.atomicreference; import java.util.regex.Matcher; import java.util.regex.Pattern; /** * @author mazhen * @className FilterHeadersUtil * @Description 过滤器请求/响应工具类 * @date 2020/10/29 9:31 */ public final class FilterRequestResponseUtil { /** * spring cloud gateway 获取post请求的body体 * @param body * @return */ public static String resolveBodyFromrequest( Flux body){ atomicreference bodyRef = new atomicreference(); // 缓存读取的request body信息 body.subscribe(dataBuffer -> { CharBuffer charBuffer = StandardCharsets.UTF_8.decode(dataBuffer.asByteBuffer()); DataBufferUtils.release(dataBuffer); bodyRef.set(charBuffer.toString()); }); //获取request body return bodyRef.get(); } /** * 读取body内容 * @param body * @return */ public static String resolveBodyFromrequest2( Flux body){ StringBuilder sb = new StringBuilder(); body.subscribe(buffer -> { byte[] bytes = new byte[buffer.readableByteCount()]; buffer.read(bytes); DataBufferUtils.release(buffer); String bodyString = new String(bytes, StandardCharsets.UTF_8); sb.append(bodyString); }); return formatStr(sb.toString()); } /** * 去掉空格,换行和制表符 * @param str * @return */ private static String formatStr(String str){ if (str != null && str.length() > 0) { Pattern p = Pattern.compile("\s*|t|r|n"); Matcher m = p.matcher(str); return m.replaceAll(""); } return str; } }
解析body的内容，网上普遍是上面的两种方式,亲测resolveBodyFromrequest方法解析body中的数据，没有1024字节的限制。
ps：我传的参数有1万多字节。。。。。。。
大家可以按需所选。
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