redis的scan使用方法及在spring框架使用详解

SCAN cursor [MATCH pattern] [COUNT count]

SCAN 0          # 第一次调用，返回新游标和部分键
SCAN 123        # 使用上次返回的游标继续迭代，直到返回0

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.connection.ScanOptions;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import java.util.ArrayList;
import java.util.List;
@Service
public class RedisScanService {
    @Autowired
    private StringRedisTemplate redisTemplate;
    /**
     * 使用SCAN命令遍历所有符合条件的键
     * @param pattern 键匹配模式，如 "user:*"
     * @return 符合条件的键列表
     */
    public List<String> scanKeys(String pattern) {
        List<String> keys = new ArrayList<>();
        RedisConnection connection = redisTemplate.getConnectionFactory().getConnection();
        // 设置ScanOptions，指定匹配模式和COUNT值
        ScanOptions options = ScanOptions.scanOptions()
                .match(pattern)
                .count(100)  // 每次迭代的建议数量
                .build();
        // 使用Cursor迭代
        try (Cursor<byte[]> cursor = connection.scan(options)) {
            while (cursor.hasNext()) {
                keys.add(new String(cursor.next()));
            }
        } catch (Exception e) {
            // 处理异常
            e.printStackTrace();
        } finally {
            // 关闭连接（try-with-resources已自动处理）
        }
        return keys;
    }
}

public class RedisPagedScanner {
    private final StringRedisTemplate redisTemplate;
    private String cursor = "0";  // 初始游标
    public RedisPagedScanner(StringRedisTemplate redisTemplate) {
        this.redisTemplate = redisTemplate;
    }
    /**
     * 获取下一页的键
     * @param pattern 匹配模式
     * @param pageSize 每页大小
     * @return 键列表及是否有下一页
     */
    public PageResult scanNextPage(String pattern, int pageSize) {
        List<String> keys = new ArrayList<>();
        boolean hasNext = false;
        RedisConnection connection = redisTemplate.getConnectionFactory().getConnection();
        ScanOptions options = ScanOptions.scanOptions()
                .match(pattern)
                .count(pageSize)
                .build();
        try (Cursor<byte[]> cursor = connection.scan(options)) {
            while (cursor.hasNext()) {
                keys.add(new String(cursor.next()));
            }
            // 更新游标状态
            this.cursor = cursor.getCursorId();
            hasNext = !cursor.isClosed();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return new PageResult(keys, hasNext);
    }
    public static class PageResult {
        private final List<String> keys;
        private final boolean hasNext;
        public PageResult(List<String> keys, boolean hasNext) {
            this.keys = keys;
            this.hasNext = hasNext;
        }
        // getters
    }
}