重温经典，曾经风靡一时的阿里内网Redis开发参考手册

Redis：

Redis（Remote Dictionary Server )，即远程字典服务，是一个开源的使用ANSI C语言编写、支持网络、可基于内存亦可持久化的日志型、Key-Value数据库，并提供多种语言的API。从2010年3月15日起，Redis的开发工作由VMware主持。从2013年5月开始，Redis的开发由Pivotal赞助。

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今天要给大家介绍的就是曾经火爆阿里的redis开发运维实战指南，如今这本书再次上了热榜，所以今天小编就给大家分享出这本书的内容：

• redis特性：

其余的内容就不给大家做详细的展示了，需要获取的小伙伴

package com.example.demo;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Collections;
import java.util.List;

import org.bouncycastle.util.encoders.Hex;
import reactor.core.publisher.Mono;

import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
import org.springframework.http.codec.HttpMessageReader;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.util.Assert;
import org.springframework.web.reactive.function.server.HandlerStrategies;
import org.springframework.web.reactive.function.server.ServerRequest;

import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.CACHED_SERVER_HTTP_REQUEST_DECORATOR_ATTR;

/**
 * This filter hashes the request body, placing the value in the X-Hash header.
 * Note: This causes the gateway to be memory constrained.
 * Sample usage: RequestHashing=SHA-256
 */
@Component
public class RequestHashingGatewayFilterFactory extends
        AbstractGatewayFilterFactory {

    private static final String HASH_ATTR = "hash";
    private static final String HASH_HEADER = "X-Hash";
    private final List> messageReaders =
            HandlerStrategies.withDefaults().messageReaders();

    public RequestHashingGatewayFilterFactory() {
        super(Config.class);
    }

    @Override
    public GatewayFilter apply(Config config) {
        MessageDigest digest = config.getMessageDigest();
        return (exchange, chain) -> ServerWebExchangeUtils
                .cacheRequestBodyAndRequest(exchange, (httpRequest) -> ServerRequest
                    .create(exchange.mutate().request(httpRequest).build(),
                            messageReaders)
                    .bodyToMono(String.class)
                    .doOnNext(requestPayload -> exchange
                            .getAttributes()
                            .put(HASH_ATTR, computeHash(digest, requestPayload)))
                    .then(Mono.defer(() -> {
                        ServerHttpRequest cachedRequest = exchange.getAttribute(
                                CACHED_SERVER_HTTP_REQUEST_DECORATOR_ATTR);
                        Assert.notNull(cachedRequest, 
                                "cache request shouldn't be null");
                        exchange.getAttributes()
                                .remove(CACHED_SERVER_HTTP_REQUEST_DECORATOR_ATTR);

                        String hash = exchange.getAttribute(HASH_ATTR);
                        cachedRequest = cachedRequest.mutate()
                                .header(HASH_HEADER, hash)
                                .build();
                        return chain.filter(exchange.mutate()
                                .request(cachedRequest)
                                .build());
                    })));
    }

    @Override
    public List shortcutFieldOrder() {
        return Collections.singletonList("algorithm");
    }

    private String computeHash(MessageDigest messageDigest, String requestPayload) {
        return Hex.toHexString(messageDigest.digest(requestPayload.getBytes()));
    }

    static class Config {

        private MessageDigest messageDigest;

        public MessageDigest getMessageDigest() {
            return messageDigest;
        }

        public void setAlgorithm(String algorithm) throws NoSuchAlgorithmException {
            messageDigest = MessageDigest.getInstance(algorithm);
        }
    }
}