功能：

• getMasterNames 從Sentinel集群從獲取master名稱列表

依賴：

<dependency>
    <groupId>redis.clients</groupId>
    <artifactId>jedis</artifactId>
    <version>2.8.1</version>
</dependency>

源碼：

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Properties;
import java.util.Set;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import redis.clients.jedis.HostAndPort;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.exceptions.JedisConnectionException;

/**
 * @author Dotions 2016年4月7日 下午4:12:11
 */
public class RedisSentinelUtils {

    private static final Logger LOG = LoggerFactory.getLogger(RedisSentinelUtils.class);

    /**
     * 從 Sentinel 集群中獲取 Master 名稱列表
     * Set value format is ip:port
     */
    public static Set<String> getMasterNames(Set<String> sentinels) {

        if (sentinels == null || sentinels.isEmpty()) {
            return Collections.emptySet();
        }

        Set<String> masterNames = new LinkedHashSet<String>();
        Iterator<String> it = sentinels.iterator();
        Jedis sentinel = null;
        String shap = null;

        while (it.hasNext()) {
            shap = it.next();
            try {
                final HostAndPort hap = toHostAndPort(Arrays.asList(shap.split(":")));

                sentinel = new Jedis(hap.getHost(), hap.getPort());

                String sInfo = sentinel.info();

                if (StringUtils.isNotBlank(sInfo)) {
                    InputStream is = new ByteArrayInputStream(sInfo.getBytes());
                    Properties p = new Properties();
                    p.load(is);

                    // check master number
                    int masterN = Integer.parseInt(p.getProperty("sentinel_masters"));

                    if (masterN > 0) {
                        String val = null;
                        String status = null;
                        String masterName = null;
                        for (int i = 0; i < masterN; i++) {
                            val = p.getProperty("master" + i);
                            String[] kv = val.split(",");

                            status = kv[1].split("=")[1];
                            masterName = kv[0].split("=")[1];

                            // Master status=ok
                            if ("ok".equals(status)) {
                                masterNames.add(masterName);
                            }
                            LOG.info("masterName={}, status={}", masterName, status);
                        }
                    } else {
                        LOG.info("Not found any master in sentinel {}", shap);
                    }
                } else {
                    LOG.error("Sentinel command execute fail, result is blank.");
                }
            } catch (JedisConnectionException ce) {
                sentinels.remove(shap);
                LOG.error(String.format("[%s] connection exception, cause by: ", shap), ce);
            } catch (Exception e) {
                LOG.error(String.format("[%s] runtime exception, cause by: ", shap), e);
            } finally {
                sentinel.close();
            }
        }
        return masterNames;
    }

    private static HostAndPort toHostAndPort(List<String> hostAndPort) {
        return new HostAndPort(hostAndPort.get(0), Integer.parseInt(hostAndPort.get(1)));
    }
}