I wrote this program to connect with my database which is on the same computer but i found a net connection error each time. com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
import java.sql.*;
public class Demo {
public static void main(String[] args) {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/db","username","pwd");
Statement stmt = connection.createStatement();
String str="SHOW TABLES";
ResultSet resultSet=stmt.executeQuery(str);
while (resultSet.next()) {
System.out.println(resultSet.getString(1));
}
}catch(Exception e){
e.printStackTrace();
}
}
}
My Stacktrace is:-
com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.ConnectException
MESSAGE: Connection refused: connect
STACKTRACE:
java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
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(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at Demo.main(Demo.java:8)
** END NESTED EXCEPTION **
Last packet sent to the server was 0 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(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at Demo.main(Demo.java:8)
Try this:
DriverManager.getConnection("jdbc:mysql://localhost:3306/dbname","username","password");
If this is not sorted out go to where you installed Mysql and open MySQL Notifier and check server is running or not if not start it and then try executing your program.
This error was mainly due to Mysql server not reachable or not running. Check with below points:
1. Check your DB Connection whether MYSQL is up and running.
2. Check if you are able to connect from command prompt
3. Restart the mysql server and try again.
Related
I am face with a problem this day. I have tried to make a shakeout with my database, which is Oracle 11g installed localy on my pc and using JAR Ojdbc6, to connect on it using few line of java code. But anything what I have tried wasn't worked.
Tried :
- Connection with SQL DEV =>is worked
- Start Listener => All ready started
- Try to change the Ip from the URL => still can't connect
I see that is a generic error, but no one has a good response. I can't understand why with SQL DEV is working but with Eclipse not.
I Hope that someone can' help me,
This is my code :
package testare;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.SQLException;
public class oracle {
public static void main(String[] argv) {
System.out.println("-------- Oracle JDBC Connection Testing ------");
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
} catch (ClassNotFoundException e) {
System.out.println("Where is your Oracle JDBC Driver?");
e.printStackTrace();
return;
}
System.out.println("Oracle JDBC Driver Registered!");
Connection connection = null;
try {
connection = DriverManager.getConnection(
"jdbc:oracle:thin:#localhost:1521/orcl", "hr","hr");
} catch (SQLException e) {
System.out.println("Connection Failed! Check output console");
e.printStackTrace();
return;
}
if (connection != null) {
System.out.println("You made it, take control your database now!");
} else {
System.out.println("Failed to make connection!");
}
}
}
This is my Error:
-------- Oracle JDBC Connection Testing ------
Oracle JDBC Driver Registered!
Connection Failed! Check output console
java.sql.SQLException: The Network Adapter could not establish the connection
at oracle.jdbc.driver.SQLStateMapping.newSQLException(SQLStateMapping.java:70)
at oracle.jdbc.driver.DatabaseError.newSQLException(DatabaseError.java:133)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:199)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:480)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:413)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:508)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:203)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:33)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:510)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at testare.oracle.main(oracle.java:31)
Caused by: oracle.net.ns.NetException: The Network Adapter could not establish the connection
at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:328)
at oracle.net.resolver.AddrResolution.resolveAndExecute(AddrResolution.java:421)
at oracle.net.ns.NSProtocol.establishConnection(NSProtocol.java:630)
at oracle.net.ns.NSProtocol.connect(NSProtocol.java:329)
at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:966)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:292)
... 7 more
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:127)
at oracle.net.nt.ConnOption.connect(ConnOption.java:126)
at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:306)
... 12 more
I think the correct URL would be jdbc:oracle:thin:#localhost:1521:orcl
Am trying to connect DB2 database in java but it throwing error, I can't find what issue was that. I added db2jcc.jar and here I show my complete database connectivity code.
public class ConnectionExample {
public static void main(String[] args) {
String jdbcClassName="com.ibm.db2.jcc.DB2Driver";
String url="jdbc:db2://localhost:50000/TestDb";
String user="user";
String password="pass#123";
Connection connection = null;
try {
//Load class into memory
Class.forName(jdbcClassName);
//Establish connection
connection = DriverManager.getConnection(url, user, password);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally{
if(connection!=null){
System.out.println("Connected successfully.");
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
}
Am trying to connect DB2 database with the above code but it throws error.
com.ibm.db2.jcc.am.DisconnectNonTransientConnectionException: [jcc][t4][2043][11550][3.63.123] Exception java.net.ConnectException: Error opening socket to server localhost/127.0.0.1 on port 50,000 with message: Connection refused: connect. ERRORCODE=-4499, SQLSTATE=08001
at com.ibm.db2.jcc.am.fd.a(fd.java:321)
at com.ibm.db2.jcc.am.fd.a(fd.java:340)
at com.ibm.db2.jcc.t4.xb.a(xb.java:433)
at com.ibm.db2.jcc.t4.xb.<init>(xb.java:90)
at com.ibm.db2.jcc.t4.a.z(a.java:347)
at com.ibm.db2.jcc.t4.b.a(b.java:1974)
at com.ibm.db2.jcc.am.ib.a(ib.java:691)
at com.ibm.db2.jcc.am.ib.<init>(ib.java:644)
at com.ibm.db2.jcc.t4.b.<init>(b.java:330)
at com.ibm.db2.jcc.DB2SimpleDataSource.getConnection(DB2SimpleDataSource.java:231)
at com.ibm.db2.jcc.DB2SimpleDataSource.getConnection(DB2SimpleDataSource.java:197)
at com.ibm.db2.jcc.DB2Driver.connect(DB2Driver.java:472)
at com.ibm.db2.jcc.DB2Driver.connect(DB2Driver.java:113)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at ConnectionExample.main(ConnectionExample.java:18)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at com.ibm.db2.jcc.t4.x.run(x.java:38)
at java.security.AccessController.doPrivileged(Native Method)
at com.ibm.db2.jcc.t4.xb.a(xb.java:419)
... 13 more
Hope Someone helps me to find out the solution. Thanks
Actually the port 50000 is not opened that is the reason I got the error after change that port to 51020 it works fine also it connects with database.
String url="jdbc:db2://localhost:51020/TestDb";
Thanks
Cause
A possible cause for this problem is that TCP/IP is not properly enabled on your DB2 database server.
Resolving the problem
Use the db2set DB2COMM command from the DB2 command window to start the TCP/IP connection:
db2set DB2COMM=protocol_names
For example, to set the database manager to start connection managers for the TCP/IP communication protocols, enter the following commands:
db2set DB2COMM=tcpip
db2stop
db2start
Source: https://www-304.ibm.com/support/docview.wss?uid=swg21403644
I am attempting to create a client/server using the SSL communication. I followed the instructions listed here (https://www.rabbitmq.com/ssl.html).
I am greeted with this error:
while running the server :
java.net.SocketException: Connection reset
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:113)
at java.net.SocketOutputStream.write(SocketOutputStream.java:153)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)
at java.io.DataOutputStream.flush(DataOutputStream.java:123)
at com.rabbitmq.client.impl.SocketFrameHandler.sendHeader(SocketFrameHandler.java:129)
at com.rabbitmq.client.impl.SocketFrameHandler.sendHeader(SocketFrameHandler.java:134)
at com.rabbitmq.client.impl.AMQConnection.start(AMQConnection.java:277)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:678)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:722)
while using the client :
Exception in thread "main" java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at sun.security.ssl.InputRecord.readFully(Unknown Source)
at sun.security.ssl.InputRecord.read(Unknown Source)
at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source)
at sun.security.ssl.SSLSocketImpl.waitForClose(Unknown Source)
at sun.security.ssl.HandshakeOutStream.flush(Unknown Source)
at sun.security.ssl.Handshaker.kickstart(Unknown Source)
at sun.security.ssl.SSLSocketImpl.kickstartHandshake(Unknown Source)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source)
at sun.security.ssl.SSLSocketImpl.writeRecord(Unknown Source)
at sun.security.ssl.AppOutputStream.write(Unknown Source)
at java.io.BufferedOutputStream.flushBuffer(Unknown Source)
at java.io.BufferedOutputStream.flush(Unknown Source)
at java.io.DataOutputStream.flush(Unknown Source)
at com.rabbitmq.client.impl.SocketFrameHandler.sendHeader(SocketFrameHandler.java:129)
at com.rabbitmq.client.impl.SocketFrameHandler.sendHeader(SocketFrameHandler.java:134)
at com.rabbitmq.client.impl.AMQConnection.start(AMQConnection.java:277)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:678)
at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:722)
at rmqClient.simpleSSL.main(simpleSSL.java:23)
here's my rabbit.config file :
[
{ssl, [{versions, ['tlsv1.2', 'tlsv1.1']}]},
{
rabbit,
[
{ssl_listeners, [5675]},
{ssl_options, [{cacertfile,"sslConn/ca_certificate.pem"},
{certfile, "sslConn/server_certificate.pem"},
{keyfile, "sslConn/server_key.pem"},
{versions, ['tlsv1.2', 'tlsv1.1']},
{ciphers, [{ecdhe_ecdsa,aes_128_cbc,sha256},
{ecdhe_ecdsa,aes_256_cbc,sha}]}
]},
{tcp_listeners, [5672]},
{loopback_users, []}
]
}
].
here's also my client code :
factory.setHost("10.3.9.139");
factory.setPort(5673);
factory.setUsername("User1");
factory.setPassword("User1");
factory.useSslProtocol();
Connection conn = factory.newConnection();
Channel channel = conn.createChannel();
channel.queueDeclare("rabbitmq-java-test", false, true, true, null);
channel.basicPublish("", "rabbitmq-java-test", null, "Hello, World".getBytes());
java.net.SocketException: Connection reset is generally speaking caused by remote peer closed connection.
I guess your SSL config didn't fit well with server.
Suggestion here is to debug SSL connection to find root cause.
Try to append this system property to your JVM params:
-Djavax.net.debug=all
More details here
I was able to fix this in Java 1.7 by specifying:
SSLContext sc = SSLContext.getInstance("TLSv1.2");
In the v configuration you have set port 5675 for SSL listener, but in code you are using 5673.
I am new to the concept of OLAP DB.
Please excuse me if I missed out something in the Connection String.
I am trying to connect to connect to Microsoft Analysis Server(which is in different Domain) from my System.
While Connecting I am getting below Error.
Can you please let me know, what am I doing wrong?
I have executed the Steps Mentioned in :
https://msdn.microsoft.com/en-us/library/gg492140.aspx
and referred to the below link for connection to the Cube:
http://www.matthewgodding.com/articles/2010/2/27/getting-data-from-sql-analysis-services-using-java-and-olap4.html
After connecting to the CUbe, I need to execute MDX Query.
Please find the snippet of the code I am using:
public static void main(String[] args) {
try {
Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");
final Connection connection = DriverManager
.getConnection("jdbc:xmla:Server=http://Remote_Server_IPAddress/OLAP/msmdpump.dll;"
+ "Catalog=MyCatalog;"
+ "User='Domian\\Username';" \\ This is the Username to login to the Server
+ "Password='Password';" \\ This is the Password to login to the Server
+ "Cube=Cube;"); \\This is the Cube Name
I get the below Exception when I execute the program:
Exception:
java.lang.RuntimeException: org.olap4j.OlapException: This connection encountered an exception while executing a query.
at org.olap4j.driver.xmla.DeferredNamedListImpl.getList(DeferredNamedListImpl.java:96)
at org.olap4j.driver.xmla.DeferredNamedListImpl.size(DeferredNamedListImpl.java:116)
at org.olap4j.driver.xmla.XmlaOlap4jConnection.getOlapDatabase(XmlaOlap4jConnection.java:451)
at org.olap4j.driver.xmla.XmlaOlap4jConnection.getDatabase(XmlaOlap4jConnection.java:444)
at org.sid.practise.CheckConnection.main(CheckConnection.java:79)
Caused by: org.olap4j.OlapException: This connection encountered an exception while executing a query.
at org.olap4j.driver.xmla.XmlaHelper.createException(XmlaHelper.java:43)
at org.olap4j.driver.xmla.XmlaOlap4jConnection.executeMetadataRequest(XmlaOlap4jConnection.java:878)
at org.olap4j.driver.xmla.XmlaOlap4jDatabaseMetaData.getMetadata(XmlaOlap4jDatabaseMetaData.java:137)
at org.olap4j.driver.xmla.XmlaOlap4jDatabaseMetaData.getMetadata(XmlaOlap4jDatabaseMetaData.java:67)
at org.olap4j.driver.xmla.XmlaOlap4jDatabaseMetaData.getDatabaseProperties(XmlaOlap4jDatabaseMetaData.java:1044)
at org.olap4j.driver.xmla.XmlaOlap4jConnection.makeConnectionPropertyList(XmlaOlap4jConnection.java:324)
at org.olap4j.driver.xmla.XmlaOlap4jConnection.generateRequest(XmlaOlap4jConnection.java:1037)
at org.olap4j.driver.xmla.XmlaOlap4jConnection.populateList(XmlaOlap4jConnection.java:849)
at org.olap4j.driver.xmla.DeferredNamedListImpl.populateList(DeferredNamedListImpl.java:136)
at org.olap4j.driver.xmla.DeferredNamedListImpl.getList(DeferredNamedListImpl.java:90)
... 4 more
Caused by: org.olap4j.driver.xmla.proxy.XmlaOlap4jProxyException: This proxy encountered an exception while processing the query.
at org.olap4j.driver.xmla.proxy.XmlaOlap4jHttpProxy.getResponse(XmlaOlap4jHttpProxy.java:181)
at org.olap4j.driver.xmla.proxy.XmlaOlap4jAbstractHttpProxy.get(XmlaOlap4jAbstractHttpProxy.java:181)
at org.olap4j.driver.xmla.proxy.XmlaOlap4jHttpProxy.get(XmlaOlap4jHttpProxy.java:42)
at org.olap4j.driver.xmla.XmlaOlap4jConnection.executeMetadataRequest(XmlaOlap4jConnection.java:876)
... 12 more
Caused by: java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.io.BufferedInputStream.fill(Unknown Source)
at java.io.BufferedInputStream.read1(Unknown Source)
at java.io.BufferedInputStream.read(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTP(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTP(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at org.olap4j.driver.xmla.proxy.XmlaOlap4jHttpProxy.getResponse(XmlaOlap4jHttpProxy.java:136)
It's difficult to know what went wrong for you. Few things you could do,
Don't specify cube in connection. This is not listed as property in XMLA driver.
You can install fiddler and see what's going on with the requests.
Not sure if single quotes are needed in user name and password.
I'm trying to generate some reports to my system using Jasper reports. I'm suing basic JDBC connection method to establish a connection to my SQL Server 2000. Here is my code snippet:
public static Connection getConnection()throws ClassNotFoundException, SQLException
{
Class.forName(driver);
Connection conn = DriverManager.getConnection(connectString, user, password);
return conn;
}
But I'm getting a SQL incorrect syntax exception.
Caused by: java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC][SQLServer]Line 2: Incorrect syntax near '|'.
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processErrorToken(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReplyToken(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSExecuteRequest.processReplyToken(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReply(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplStatement.getNextResultType(Unknown Source)
at com.microsoft.jdbc.base.BaseStatement.commonTransitionToState(Unknown Source)
at com.microsoft.jdbc.base.BaseStatement.postImplExecute(Unknown Source)
at com.microsoft.jdbc.base.BasePreparedStatement.postImplExecute(Unknown Source)
at com.microsoft.jdbc.base.BaseStatement.commonExecute(Unknown Source)
at com.microsoft.jdbc.base.BaseStatement.executeQueryInternal(Unknown Source)
at com.microsoft.jdbc.base.BasePreparedStatement.executeQuery(Unknown Source)
at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:478)
Thanks.
The first line of the exception you get says:
Line 2: Incorrect syntax near '|'.
Check to see where you have the '|' in your source. In case of doubt try these:
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
conn = DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433", user, password);
Make also sure your jars are at the right place.