具体情境如下,首先在linux机器上开启redis,

配置如下~

port:6379

ip:192.168.135.145

做法~在win下的idea连接linux中已经开启的redis,

看java后端代码~

```java

import redis.clients.jedis.Jedis;

import redis.clients.jedis.JedisPool;

public class jredisDemo01 {

    public static void main(String[] args) {

  /*    JedisPool jedisPool = new JedisPool("192.168.135.145",6379);

        Jedis jedis1 = jedisPool.getResource();

        jedis1.set("person","name");*/

        try {

            Jedis jedis = new Jedis("192.168.135.145",6379);

            jedis.set("fruit","lisi");

            String fruit = jedis.get("fruit");

            System.out.println(fruit);

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}

```

运行后结果报错~不能处理DNSname,根据提示查找可能是DNS解析问题,于是将host文件修改,添加了 192.168.135.145  redis

问题依旧存在;

```java

redis.clients.jedis.exceptions.JedisConnectionException: Failed to connect to any host resolved for DNS name.

at redis.clients.jedis.DefaultJedisSocketFactory.connectToFirstSuccessfulHost(DefaultJedisSocketFactory.java:63)

at redis.clients.jedis.DefaultJedisSocketFactory.createSocket(DefaultJedisSocketFactory.java:87)

at redis.clients.jedis.Connection.connect(Connection.java:180)

at redis.clients.jedis.Connection.sendCommand(Connection.java:152)

at redis.clients.jedis.Connection.executeCommand(Connection.java:121)

at redis.clients.jedis.Jedis.set(Jedis.java:4725)

at com.gavin.jredisDemo01.main(jredisDemo01.java:16)

Suppressed: java.net.SocketTimeoutException: connect timed out

at java.base/java.net.PlainSocketImpl.waitForConnect(Native Method)

at java.base/java.net.PlainSocketImpl.socketConnect(PlainSocketImpl.java:107)

at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399)

at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242)

at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224)

at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403)

at java.base/java.net.Socket.connect(Socket.java:591)

at redis.clients.jedis.DefaultJedisSocketFactory.connectToFirstSuccessfulHost(DefaultJedisSocketFactory.java:73)

... 6 more

```

异常~`Failed to connect to any host resolved for DNS name.  connect timed out`

异常发生之前----->>

1,注掉redis配置文件中bind--->>使得外部可以连接到redis  (也可以指定连接地址)


2,保护模式已经关闭--->>不用输入密码可以连接

3,以设置守护模式 -->>使得redis可以在后台运行

可能是端口号没开放?

最后查看端口号是否对外开放~

```c

[root@localhost bin]# sudo firewall-cmd --zone=public --add-port=6379/tcp --permanent

success

[root@localhost bin]# systemctl restart firewalld

```

>注意~之后要重启防火墙,使得开放端口生效

再次运行代码~正常了