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The editor will share with you how to implement the Bloom filter in SpringBoot+Redis. I hope you will get something after reading this article. Let's discuss it together.

Brief introduction

I am not going to repeat the detailed introduction of the Bloom filter here.

We first know that BloomFilter uses a byte array of m bit, uses k hash functions, adds an element: maps the element to k positions in the byte array through k times hash, and sets the byte of the corresponding position to 1. Query whether the element exists: hash the element k times to get k positions. If the bit of the corresponding k locations is 1, it is considered to exist, otherwise it does not exist.

There is already a specific implementation in Guava, but in our actual production environment, local storage is often unable to meet our actual needs. So at this point, we need to use redis.

Redis install Bloom Filtergit clone https://github.com/RedisLabsModules/redisbloom.gitcd redisbloommake # compile vi redis.conf## add configuration loadmodule / usr/local/web/redis/RedisBloom-1.1.1/rebloom.so##redis restart # off. / redis-cli-h 127.0.0.1-p 6379 shutdown# start. / redis-server.. / redis.conf & basic directive # create Bloom filter And set an expected error rate and initial size bf.reserve userid 0.0110000 to add an element bf.add userid 'sbc@163.com'# to the filter to determine whether the value of the specified key exists in the bloomfilter, exists: returns 1, does not exist: returns 0bf.exists userid' sbc@163.com' combined with SpingBoot

Build a simple springboot framework

Mode one

Configuration

4.0.0 com.bloom test-bloomfilter 1.0-SNAPSHOT org.springframework.boot spring-boot-starter-parent 1.5.8.RELEASE org.springframework.boot spring-boot-starter org.apache.commons commons-lang3 3.0.1

Redis itself has a good implementation of the Bloom filter. On the java side, we can directly import the jar package of redisson.

Org.redisson redisson 3.8.2

Inject Redisson instances into the SpringIOC container

@ Configurationpublic class RedissonConfig {@ Value ("${redisson.redis.address}") private String address; @ Value ("${redisson.redis.password}") private String password; @ Bean public Config redissionConfig () {Config config = new Config (); SingleServerConfig singleServerConfig = config.useSingleServer (); singleServerConfig.setAddress (address); if (StringUtils.isNotEmpty (password)) {singleServerConfig.setPassword (password) } return config;} @ Bean public RedissonClient redissonClient () {return Redisson.create (redissionConfig ());}}

Configuration file

Redisson.redis.address=redis://127.0.0.1:6379redisson.redis.password=

Finally, test our Bloom filter.

SpringBootApplicationpublic class BloomApplication {public static void main (String [] args) {ConfigurableApplicationContext context = SpringApplication.run (BloomApplication.class, args); RedissonClient redisson = context.getBean (RedissonClient.class); RBloomFilter bf = redisson.getBloomFilter ("test-bloom-filter"); bf.tryInit (100000L, 0.03); Set set = new HashSet (1000); List list = new ArrayList (1000) / populate the Bloom filter with data. To test the reality, we recorded 1000 uuid and another 9000 as interference data for (int I = 0; I < 10000; iSuppli +) {String uuid = UUID.randomUUID () .toString (); if (I)

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