【项目】仿牛客网社区开发 第7章 项目进阶 构建安全高效的企业服务 4 Redis高级数据类型_仿牛客 redis高级数据类型

【项目】仿牛客网社区开发

第7章 项目进阶 构建安全高效的企业服务

4 Redis高级数据类型

• HyperLogLog
  • 采用一种基数算法，用于完成独立总数的统计。
  • 占据空间小，无论统计多少个数据，只占12K的内存空间。
  • 不精确的统计算法，标准误差为 0.81% 。
• Bitmap
  • 不是一种独立的数据结构，实际上就是字符串。
  • 支持按位存取数据，可以将其看成是byte数组。
  • 适合存储索大量的连续的数据的布尔值。

写一点程序体会一下咋用这两种数据类型

    // 统计20万个重复数据的独立总数.
    @Test
    public void testHyperLogLog() {
        String redisKey = "test:hll:01";

        for (int i = 1; i <= 100000; i++) {
            redisTemplate.opsForHyperLogLog().add(redisKey, i);
        }

        for (int i = 1; i <= 100000; i++) {
            int r = (int) (Math.random() * 100000 + 1);
            redisTemplate.opsForHyperLogLog().add(redisKey, r);
        }

        long size = redisTemplate.opsForHyperLogLog().size(redisKey);
        System.out.println(size);
    }
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运行结果

12 KB

    // 将3组数据合并, 再统计合并后的重复数据的独立总数.
    @Test
    public void testHyperLogLogUnion() {
        String redisKey2 = "test:hll:02";
        for (int i = 1; i <= 10000; i++) {
            redisTemplate.opsForHyperLogLog().add(redisKey2, i);
        }

        String redisKey3 = "test:hll:03";
        for (int i = 5001; i <= 15000; i++) {
            redisTemplate.opsForHyperLogLog().add(redisKey3, i);
        }

        String redisKey4 = "test:hll:04";
        for (int i = 10001; i <= 20000; i++) {
            redisTemplate.opsForHyperLogLog().add(redisKey4, i);
        }

        String unionKey = "test:hll:union";
        redisTemplate.opsForHyperLogLog().union(unionKey, redisKey2, redisKey3, redisKey4);

        long size = redisTemplate.opsForHyperLogLog().size(unionKey);
        System.out.println(size);
    }
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运行结果

    // 统计一组数据的布尔值
    @Test
    public void testBitMap() {
        String redisKey = "test:bm:01";

        // 记录
        redisTemplate.opsForValue().setBit(redisKey, 1, true);
        redisTemplate.opsForValue().setBit(redisKey, 4, true);
        redisTemplate.opsForValue().setBit(redisKey, 7, true);

        // 查询
        System.out.println(redisTemplate.opsForValue().getBit(redisKey, 0));
        System.out.println(redisTemplate.opsForValue().getBit(redisKey, 1));
        System.out.println(redisTemplate.opsForValue().getBit(redisKey, 2));

        // 统计
        Object obj = redisTemplate.execute(new RedisCallback() {
            @Override
            public Object doInRedis(RedisConnection connection) throws DataAccessException {
                return connection.bitCount(redisKey.getBytes());
            }
        });

        System.out.println(obj);
    }
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运行结果

    // 统计3组数据的布尔值, 并对这3组数据做OR运算.
    @Test
    public void testBitMapOperation() {
        String redisKey2 = "test:bm:02";
        redisTemplate.opsForValue().setBit(redisKey2, 0, true);
        redisTemplate.opsForValue().setBit(redisKey2, 1, true);
        redisTemplate.opsForValue().setBit(redisKey2, 2, true);

        String redisKey3 = "test:bm:03";
        redisTemplate.opsForValue().setBit(redisKey3, 2, true);
        redisTemplate.opsForValue().setBit(redisKey3, 3, true);
        redisTemplate.opsForValue().setBit(redisKey3, 4, true);

        String redisKey4 = "test:bm:04";
        redisTemplate.opsForValue().setBit(redisKey4, 4, true);
        redisTemplate.opsForValue().setBit(redisKey4, 5, true);
        redisTemplate.opsForValue().setBit(redisKey4, 6, true);

        String redisKey = "test:bm:or";
        Object obj = redisTemplate.execute(new RedisCallback() {
            @Override
            public Object doInRedis(RedisConnection connection) throws DataAccessException {
                connection.bitOp(RedisStringCommands.BitOperation.OR,
                        redisKey.getBytes(), redisKey2.getBytes(), redisKey3.getBytes(), redisKey4.getBytes());
                return connection.bitCount(redisKey.getBytes());
            }
        });

        System.out.println(obj);

        System.out.println(redisTemplate.opsForValue().getBit(redisKey, 0));
        System.out.println(redisTemplate.opsForValue().getBit(redisKey, 1));
        System.out.println(redisTemplate.opsForValue().getBit(redisKey, 2));
        System.out.println(redisTemplate.opsForValue().getBit(redisKey, 3));
        System.out.println(redisTemplate.opsForValue().getBit(redisKey, 4));
        System.out.println(redisTemplate.opsForValue().getBit(redisKey, 5));
        System.out.println(redisTemplate.opsForValue().getBit(redisKey, 6));
    }
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运行结果