Question

运行java程序连接mysql数据库是出现如下结果怎么回事？

程序：
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class ConnectionDemo
{
public static final String DBDRIVER = "org.gjt.mm.mysql.Driver";
//数据库连接地址
public static final String DBURL = "jdbc:mysql://localhost:3306/mldn";
public static final String DBUSER = "MySQLserver";//数据库连接用户名
public static final String DBPASS = "manmanw68";//数据库连接密码
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();
}
}
}
运行结果：
C:\Users\伊郁\Desktop>java ConnectionDemo
java.sql.SQLException: Access denied for user 'MySQLserver'@'localhost' (using p
assword: YES)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3603)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3535)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:934)
at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:4104)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1299)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2338)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2
371)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2163)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:794)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Sou
rce)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:407)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:378)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java
:305)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at ConnectionDemo.main(ConnectionDemo.java:23)
null
Exception in thread "main" java.lang.NullPointerException
at ConnectionDemo.main(ConnectionDemo.java:32)

Answer 1

1没有导包 2没有数据库没有建好3密码错误

追问

这三个都是对的！

Answer 2

你的用户名有问题，再有你的driver 是自己封装的么，怎么不一样？

追问

不是自己封装的！

追答

org.gjt.mm.mysql.Driver你在你的jar包中能找到相应的类么

追问

能找到

追答

应该是你的用户名和密码出了问题，你需要验证一下你用现在的用户名和密码能不能登录

Answer 3

兄弟你怎么解决的 我和你一样