Caused by java.net.ConnectException Connection timed out connect

jdbc远程连接数据库超时

标题主要可能有连个原因：mysql服务没开，防火墙没有放行3306端口

七月 14, 2020 5:04:18 下午 com.alibaba.druid.pool.DruidDataSource error
严重: create connection error, url: jdbc:mysql://192.168.184.130:3306/project_crowd, errorCode 0, state 08S01
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Last packet sent to the server was 0 ms ago.
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:403)
	at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2064)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:720)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:403)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:293)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:283)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1464)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1529)
	at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:2109)
Caused by: java.net.ConnectException: Connection timed out: connect
	at java.net.DualStackPlainSocketImpl.connect0(Native Method)
	at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
	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:606)
	at java.net.Socket.connect(Socket.java:555)
	at java.net.Socket.<init>(Socket.java:451)
	at java.net.Socket.<init>(Socket.java:261)
	at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256)
	at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:274)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:1987)
	... 12 more

错误信息：Caused by: java.net.ConnectException: Connection timed out: connect

可能的原因是开启了防火墙，拦截了连接的请求

查看防火墙状态：service iptables status

发现没有接受的3306端口

开启3306端口

命令： vim /etc/sysconfig/iptables 进入防火墙文件，输入i操作文件

esc 然后：wq退出iptables文件，然后重启防火墙

完结

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