这篇文章主要介绍了在Node.js应用中读写Redis数据库的简单方法,Redis是一个内存式高速数据库,需要的朋友可以参考下  在开始本文之前请确保安装好 Redis 和 Node.js 以及 Node.js 的 Redis 扩展 node_redis  首先创建一个新文件夹并新建文本文件 app.js 文件内容如下:  ?12345678910111213141516171819var redis = require(redis), client = redis.createClient();client.on(error, function (err) {console.log(Error err);});client.on(connect, runSample);function runSample() {// Set a valueclient.set(string key, Hello World, function (err, reply) {console.log(reply.toString());});// Get a valueclient.get(string key, function (err, reply) {console.log(reply.toString());});}  当连接到 Redis 后会调用 runSample 函数并设置一个值,紧接着便读出该值,运行的结果如下:  ?12OKHello World  我们也可以使用 EXPIRE 命令来设置对象的失效时间,代码如下:  ?123456789101112131415161718192021222324252627282930var redis = require(redis), client = redis.createClient();client.on(error, function (err) {console.log(Error err);});client.on(connect, runSample);function runSample() {// Set a value with an expirationclient.set(string key, Hello World, redis.print);// Expire in 3 secondsclient.expire(string key, 3);// This timer is only to demo the TTL// Runs every second until the timeout// occurs on the valuevar myTimer = setInterval(function() {client.get(string key, function (err, reply) {if(reply) {console.log(I live: reply.toString());} else {clearTimeout(myTimer);console.log(I expired);client.quit();}});}, 1000);}  注意: 上述使用的定时器只是为了演示 EXPIRE 命令,你必须在 Node.js 项目中谨慎使用定时器。

  运行上述程序的输出结果是:  ?12345Reply: OKI live: Hello WorldI live: Hello WorldI live: Hello WorldI expired  接下来我们检查一个值在失效之前存留了多长时间:  ?1234567891011121314151617181920212223242526272829303132333435var redis = require(redis), client = redis.createClient();client.on(error, function (err) {console.log(Error err);});client.on(connect, runSample);function runSample() {// Set a valueclient.set(string key, Hello World, redis.print);// Expire in 3 secondsclient.expire(string key, 3);// This timer is only to demo the TTL// Runs every second until the timeout// occurs on the valuevar myTimer = setInterval(function() {client.get(string key, function (err, reply) {if(reply) {console.log(I live: reply.toString());client.ttl(string key, writeTTL);} else {clearTimeout(myTimer);console.log(I expired);client.quit();}});}, 1000);}function writeTTL(err, data) {console.log(I live for this long yet: data);}  运行结果:  ?12345678Reply: OKI live: Hello WorldI live for this long yet: 2I live: Hello WorldI live for this long yet: 1I live: Hello WorldI live for this long yet: 0I expired