java jedis (redis) 无法连接

Question

我正在尝试在我的 Java 应用程序中使用 Jedis 连接到 Redis。我正在实例化一个 JedisPool 对象，当我获得资源时，它会抛出一个异常，说明它无法返回资源。奇怪的是，如果我只是实例化一个 Jedis 对象，它可以毫无问题地连接，并且我可以更改数据。

这是我的 RedisDatabase 类:

package me.joeleoli.proxylink.database;

import me.joeleoli.proxylink.ProxyLink;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;

public class RedisDatabase {

    private JedisPool pool;

    public RedisDatabase(String host, int port, String password) {
        ProxyLink.getInstance().getLogger().info("Attempting to establish Redis connection " + host + ":" + port);

        this.pool = new JedisPool(host, port);

        try (Jedis jedis = this.pool.getResource()) {
            if (password != null && !password.equals("")) {
                jedis.auth(password);
            }

            jedis.select(0);
            jedis.close();
        }
    }

    public JedisPool getPool() {
        return this.pool;
    }

}

这是我的错误:

22:16:15 [INFO] [ProxyLink] Attempting to establish Redis connection 127.0.0.1:6379
22:16:15 [WARNING] Exception encountered when loading plugin: ProxyLink
redis.clients.jedis.exceptions.JedisException: Could not return the resource to the pool
    at redis.clients.jedis.JedisPool.returnResource(JedisPool.java:106)
    at redis.clients.jedis.JedisPool.returnResource(JedisPool.java:12)
    at redis.clients.jedis.Jedis.close(Jedis.java:3206)
    at me.joeleoli.proxylink.database.RedisDatabase.<init>(RedisDatabase.java:23)
    at me.joeleoli.proxylink.ProxyLink.onEnable(ProxyLink.java:71)
    at net.md_5.bungee.api.plugin.PluginManager.enablePlugins(PluginManager.java:227)
    at net.md_5.bungee.BungeeCord.start(BungeeCord.java:273)
    at net.md_5.bungee.BungeeCordLauncher.main(BungeeCordLauncher.java:111)
    at net.md_5.bungee.Bootstrap.main(Bootstrap.java:15)
Caused by: redis.clients.jedis.exceptions.JedisException: Could not return the resource to the pool
    at redis.clients.util.Pool.returnResourceObject(Pool.java:61)
    at redis.clients.jedis.JedisPool.returnResource(JedisPool.java:103)
    ... 8 more
Caused by: java.lang.IllegalStateException: Object has already been returned to this pool or is invalid
    at org.apache.commons.pool2.impl.GenericObjectPool.returnObject(GenericObjectPool.java:551)
    at redis.clients.util.Pool.returnResourceObject(Pool.java:59)
    ... 9 more

Answer 1

您的代码的问题是在 try-with-resource block 中调用了 jedis.close()。 try-with-resource block 会在 block 退出时关闭您的资源。由于您已经关闭了资源，因此在 block 退出之前，您最终调用了两次关闭。

在 block 中删除对 jedis.close 的调用，只使用 try-with-resource 功能。