我尝试使用Java连接MYSQL数据库,其中我的SQL数据库位于localhost上。 我面临一些有关通信链路故障的问题。
public testfile() throws ClassNotFoundException, SQLException{
Connection connection = null;
try{
Class.forName("com.mysql.jdbc.Driver").newInstance();
connection = DriverManager.getConnection("jdbc:mysql://localhost/rts?user=root&password=password");
System.out.println("Connected");
}
catch(Exception ex)
{
ex.printStackTrace();
}
finally
{
if(connection != null)
connection.close();
}
}
堆栈追踪:
com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.ConnectException
MESSAGE: Connection refused
STACKTRACE:
java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:327)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:193)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:180)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:384)
at java.net.Socket.connect(Socket.java:546)
at java.net.Socket.connect(Socket.java:495)
at java.net.Socket.<init>(Socket.java:392)
at java.net.Socket.<init>(Socket.java:235)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771)
at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
at java.sql.DriverManager.getConnection(DriverManager.java:620)
at java.sql.DriverManager.getConnection(DriverManager.java:222)
at test.testfile.<init>(testfile.java:18)
at test.mainfile.main(mainfile.java:9)
** END NESTED EXCEPTION **
Last packet sent to the server was 1 ms ago.
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2847)
at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
at java.sql.DriverManager.getConnection(DriverManager.java:620)
at java.sql.DriverManager.getConnection(DriverManager.java:222)
at test.testfile.<init>(testfile.java:18)
at test.mainfile.main(mainfile.java:9)
Telnet输出:
telnet localhost 3306
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Connection closed by foreign host.
包装/软件信息:
我尝试了一些东西,但它不起作用:
我在my.cnf中更改了端口但没有效果,我改为3312 同样的错误重复和telnet显示如下:
shreya@shreya-laptop:~$ telnet localhost 3306 Trying 127.0.0.1... telnet: Unable to connect to remote host: Connection refused shreya@shreya-laptop:~$ telnet localhost 3312 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. Connection closed by foreign host.
nmap输出:
shreya@shreya-laptop:~$ nmap localhost -p 3306 Starting Nmap 5.00 ( [url]http://nmap.org[/url] ) at 2011-03-31 09:45 IST Interesting ports on localhost (127.0.0.1): PORT STATE SERVICE 3306/tcp closed mysql Nmap done: 1 IP address (1 host up) scanned in 0.11 seconds shreya@shreya-laptop:~$ nmap localhost -p 3312 Starting Nmap 5.00 ( [url]http://nmap.org[/url] ) at 2011-03-31 09:45 IST Interesting ports on localhost (127.0.0.1): PORT STATE SERVICE 3312/tcp open unknown Nmap done: 1 IP address (1 host up) scanned in 0.06 seconds
我尝试在hosts.allow中输入条目,但没有效果
我尝试重新安装mysql。通过mysql提示和c程序插入数据可以很好地工作,但不能通过java代码。
我尝试在ip表中添加规则仍然没有帮助
我尝试过不同的url字符串组合。我也尝试过不同版本的eclipse和Connector / J jar文件(最新5.1.15)
答案 0 :(得分:1)
首先尝试使用MYSQL Command Line Client
使用程序中使用的相同凭据连接到MySQL。
答案 1 :(得分:1)
java.net.ConnectException:拒绝连接
在给定的主机/端口上没有任何侦听/接受连接的东西。验证以下内容:
my.cnf
验证端口号是否确实为3306。mysqld
不应选择--skip-networking
。finally
块中的连接。答案 2 :(得分:0)
您需要向通过端口3306连接的用户授予权限......这个人有一个很好的解释:link