jdbc连接数据库时出错!!!!
原代码:
import java.sql.Connection ;
import java.sql.DriverManager ;
import java.sql.SQLException ;
public class ConnectionDemo02{public static final String DBDRIVER = "org.gjt.mm.mysql.Driver" ;public static final String DBURL = "jdbc:mysql://localhost:3306/mldn" ;public static final String DBUSER = "root" ;public static final String DBPASS = "mysqladmin" ;
public static void main(String args[]){
Connection conn = null ;
try{
Class.forName(DBDRIVER) ;
}catch(ClassNotFoundException e){
e.printStackTrace() ;
}
try{
conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS) ;
}catch(SQLException e){
e.printStackTrace() ;
}
System.out.println(conn) ;
try{
conn.close() ;
}catch(SQLException e){
e.printStackTrace() ;
}
}
};
报的错误:
com.mysql.jdbc.CommunicationsException: Communications link failure due to under
lying exception:
** BEGIN NESTED EXCEPTION **
java.net.SocketException
MESSAGE: java.net.ConnectException: Connection refused: connect
STACKTRACE:
java.net.SocketException: java.net.ConnectException: Connection refused: connect
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.ja
va:156)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:276)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2666)
at com.mysql.jdbc.Connection.<init>(Connection.java:1531)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java
:266)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at ConnectionDemo02.main(ConnectionDemo02.java:20)** END NESTED EXCEPTION **Last packet sent to the server was 0 ms ago.
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2741)
at com.mysql.jdbc.Connection.<init>(Connection.java:1531)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java
:266)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at ConnectionDemo02.main(ConnectionDemo02.java:20)
null
Exception in thread "main" java.lang.NullPointerException
at ConnectionDemo02.main(ConnectionDemo02.java:29)那位高手指点下啊!!!!!!!!!!!!!!!
补充:我的MySQL配置
CLASSPATH
.;%JAVA_HOME%/lib;%JAVA_HOME%/lib/tools.jar;%JAVA_HOME%/lib/mysql-connector-java-5.0.4-bin.jarmysql-connector-java-5.0.4-bin.jar整个放到了JDK的lib的文件夹中
原代码:
import java.sql.Connection ;
import java.sql.DriverManager ;
import java.sql.SQLException ;
public class ConnectionDemo02{public static final String DBDRIVER = "org.gjt.mm.mysql.Driver" ;public static final String DBURL = "jdbc:mysql://localhost:3306/mldn" ;public static final String DBUSER = "root" ;public static final String DBPASS = "mysqladmin" ;
public static void main(String args[]){
Connection conn = null ;
try{
Class.forName(DBDRIVER) ;
}catch(ClassNotFoundException e){
e.printStackTrace() ;
}
try{
conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS) ;
}catch(SQLException e){
e.printStackTrace() ;
}
System.out.println(conn) ;
try{
conn.close() ;
}catch(SQLException e){
e.printStackTrace() ;
}
}
};
报的错误:
com.mysql.jdbc.CommunicationsException: Communications link failure due to under
lying exception:
** BEGIN NESTED EXCEPTION **
java.net.SocketException
MESSAGE: java.net.ConnectException: Connection refused: connect
STACKTRACE:
java.net.SocketException: java.net.ConnectException: Connection refused: connect
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.ja
va:156)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:276)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2666)
at com.mysql.jdbc.Connection.<init>(Connection.java:1531)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java
:266)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at ConnectionDemo02.main(ConnectionDemo02.java:20)** END NESTED EXCEPTION **Last packet sent to the server was 0 ms ago.
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2741)
at com.mysql.jdbc.Connection.<init>(Connection.java:1531)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java
:266)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at ConnectionDemo02.main(ConnectionDemo02.java:20)
null
Exception in thread "main" java.lang.NullPointerException
at ConnectionDemo02.main(ConnectionDemo02.java:29)那位高手指点下啊!!!!!!!!!!!!!!!
补充:我的MySQL配置
CLASSPATH
.;%JAVA_HOME%/lib;%JAVA_HOME%/lib/tools.jar;%JAVA_HOME%/lib/mysql-connector-java-5.0.4-bin.jarmysql-connector-java-5.0.4-bin.jar整个放到了JDK的lib的文件夹中
解决方案 »
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