总结一下Jedis 连接 Redis 常见错误

1、SocketTimeoutException 连接超时

redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketTimeoutException: connect timed out
    at redis.clients.jedis.Connection.connect(Connection.java:154)
    at redis.clients.jedis.BinaryClient.connect(BinaryClient.java:83)
    at redis.clients.jedis.Connection.sendCommand(Connection.java:93)
    at redis.clients.jedis.Connection.sendCommand(Connection.java:88)
    at redis.clients.jedis.Jedis.get(Jedis.java:97) 

这种情况先排除是否开启了redis，或者ip，端口是否正确。如果都没问题，那八成就是防火墙了。
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
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

CentOS，root用户登陆，输入如下命令开启端口：

/sbin/iptables -I INPUT -p tcp --dport 6379 -j ACCEPT

刷新自动启动保存

/etc/rc.d/init.d/iptables save

2、Connection refused 拒绝访问

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

修改redis.conf配置文件，使用vim命令打开，找到bind那行修改后，wq保存退出，重启redis-server。

编辑后如上图，用#号注释。

3、DENIED Redis is running in protected mode （保护模式）

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:117)
    at redis.clients.jedis.Protocol.process(Protocol.java:142)
    at redis.clients.jedis.Protocol.read(Protocol.java:196)
    at redis.clients.jedis.Connection.readProtocolWithCheckingBroken(Connection.java:288)
    at redis.clients.jedis.Connection.getBinaryBulkReply(Connection.java:207)
    at redis.clients.jedis.Connection.getBulkReply(Connection.java:196)
    at redis.clients.jedis.Jedis.get(Jedis.java:98)
    at com.zyao89.jedis.JedisTest.test1(JedisTest.java:18)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

报错信息很长，但是主要是说redis开启了protected mode，这也是Redis3.2加入的新特性，开启保护模式的redis只允许本机登录，同样设置在配置文件redis.conf中，如图

这里原来是yes代表开启了保护模式，后面可以填密码也可以填no代表关闭，我们这里选择关闭保护模式，wq保存退出后再重启redis-server。

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作者：Zyao89；转载请保留此行，谢谢；

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