Google布隆过滤器

1，引入依赖

<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>21.0</version>
</dependency>
2，

package com.example.bloomfilter;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.toolkit.CollectionUtils;
import com.example.entity.Test;
import com.example.mapper.TestMapper;
import com.google.common.hash.BloomFilter;
import com.google.common.hash.Funnels;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;
import java.util.List;

/**
 * @description:
 * @createTime:2020/11/17 14:44
 * @version:1.0
 */
@Service
public class BloomFilterService {

    @Autowired
    private TestMapper testMapper;

    private BloomFilter<Integer> bf;

    /**
     * 创建布隆过滤器
     *
     * @PostConstruct：程序启动时候加载此方法
     */
    @PostConstruct
    public void initBloomFilter() {
        QueryWrapper queryWrapper = new QueryWrapper();
        List<Test> testList = testMapper.selectList(queryWrapper);
        if (CollectionUtils.isEmpty(testList)) {
            return;
        }
        //创建布隆过滤器(默认3%误差)
        bf = BloomFilter.create(Funnels.integerFunnel(), testList.size());
        for (Test test : testList) {
            bf.put(test.getId());
        }
    }

    /**
     * 判断id可能存在于布隆过滤器里面
     *
     * @param id
     * @return
     */
    public boolean testIdExists(int id) {
        return bf.mightContain(id);
    }
}



3，引入 BloomFilterService 

@Autowired
private BloomFilterService bloomFilterService;

然后调用

 bloomFilterService.testIdExists(id) 返回布尔值