Java 连接操作 Redis 出现错误

Exception in thread "main" redis.clients.jedis.exceptions.JedisConnectionException: java.net.ConnectException: Connection refused: connect
    at redis.clients.jedis.Connection.connect(Connection.java:207)
    at redis.clients.jedis.BinaryClient.connect(BinaryClient.java:93)
    at redis.clients.jedis.Connection.sendCommand(Connection.java:126)
    at redis.clients.jedis.Connection.sendCommand(Connection.java:121)
    at redis.clients.jedis.BinaryClient.ping(BinaryClient.java:106)
    at redis.clients.jedis.BinaryJedis.ping(BinaryJedis.java:195)
    at practice.RedisJava.main(RedisJava.java:13)
Caused by: java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at redis.clients.jedis.Connection.connect(Connection.java:184)
    ... 6 more

这可能是两个原因造成的，首先可能是redis的6379端口无法访问，请先在cmd中输入命令 
telnet 127.0.0.1 6379 
看看可不可以访问redis-server 机器的6379端口，如果不能访问，需要在远程机器关掉防火墙或者添加允许通过 
1）使用root用户登录，vi /etc/sysconfig/iptables，添加如图所以一行

# Generated by iptables-save v1.4.21 on Tue Nov 21 12:32:27 2017
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [1:156]-A INPUT -m state --state NEW -m tcp -p tcp --dport 6379 -j ACCEPT
COMMIT
# Completed on Tue Nov 21 12:32:27 2017

2）输入命令service iptables restart重启防火墙

或者可以直接root用户使用命令service iptables stop关闭防火墙。

防火墙检查完后，如果还是出现上述问题，说明redis还有地方需要配置，redis默认是只有本机可以访问的，想要远程访问需要修改redis.conf配置文件。 
进入redis.conf目录，并使用vi命令打开，找到bind那行修改后，wq保存退出，重启redis-server。

bind 后加的是允许访问的ip 
bind 127.0.0.1代表只有本机可以访问，可以将允许访问的ip加入，也可以直接注释掉这一行，这样所有机器都可以访问

解决上述问题后出现的新问题：DENIED Redis is running in protected mode

报错信息如下：

Exception in thread "main" redis.clients.jedis.exceptions.JedisDataException: DENIED Redis is running in protected mode because protected mode is enabled,
 no bind address was specified, no authentication password is requested to clients. In this mode connections are only accepted from the loopback interface. 
If you want to connect from external computers to Redis you may adopt one of the following solutions:
1) Just disable protected mode sending the command 'CONFIG SET protected-mode no' from the loopback interface by connecting to Redis from the same host the 
server is running, however MAKE SURE Redis is not publicly accessible from internet if you do so. Use CONFIG REWRITE to make this change permanent.
2) Alternatively you can just disable the protected mode by editing the Redis configuration file, and setting the protected mode option to 'no', and then restarting the server.
3) If you started the server manually just for testing, restart it with the '--protected-mode no' option.
4) Setup a bind address or an authentication password. NOTE: You only need to do one of the above things in order for the server to start accepting connections from the outside.
    at redis.clients.jedis.Protocol.processError(Protocol.java:127)
    at redis.clients.jedis.Protocol.process(Protocol.java:161)
    at redis.clients.jedis.Protocol.read(Protocol.java:215)
    at redis.clients.jedis.Connection.readProtocolWithCheckingBroken(Connection.java:340)
    at redis.clients.jedis.Connection.getStatusCodeReply(Connection.java:239)
    at redis.clients.jedis.Jedis.set(Jedis.java:121)
    at roy.redis.test.Test.init(Test.java:13)
    at roy.redis.test.Test.main(Test.java:8)

主要是这里的原因：redis开启了保护模式,我们可以将它设置为no;

当然,另一种安全的做法是