布隆过滤器

布隆过滤器 布隆过滤器的依赖

        
        
            com.google.guava
            guava
            23.0
        

Java代码实现

import com.google.common.hash.BloomFilter;
import com.google.common.hash.Funnels;
import java.nio.charset.Charset;

public class Demo01 {
    public static void main(String[] args) {
        //参数1:字符编码集, 参数2:加入的key的数量, 参数3: 预期的误判率
        BloomFilter bloomFilter = BloomFilter.create(Funnels.integerFunnel(), 10000000, 0.01);
        //添加数据
        bloomFilter.put("张三".hashCode());
        bloomFilter.put("李四".hashCode());
        //获取存储的数据的条数
        long l = bloomFilter.approximateElementCount();
        System.out.println("数据的长度"+l);
        //判断是否存在
        System.out.println(bloomFilter.mightContain("张三".hashCode()));//true
        System.out.println(bloomFilter.mightContain("王五".hashCode()));//false
        
        
        //参数1:字符编码集, 参数2:加入的key的数量, 参数3: 预期的误判率
        BloomFilter bloomFilter1 = BloomFilter.create(Funnels.stringFunnel(Charset.forName("utf-8")), 1000000, 0.01);
        //添加数据
        bloomFilter1.put("张三");
        bloomFilter1.put("李四");
        //判断是否存在
        System.out.println(bloomFilter1.mightContain("张三"));//true
        System.out.println(bloomFilter1.mightContain("王五"));//false
    }
}