import java.io.*;
import java.sql.*;
public class DbUtil {
      static String driverName="com.mysql.jdbc.Driver";
      static String dbUrl="jdbc:mysql://";
      static String user ="root";
      static String password ="12345678";
public DbUtil() { }
      public static java.sql.Connection connectToDb(String hostName, String databaseName)throws Exception
      {
            Connection connection=null;
            String connName = dbUrl + hostName+":3306"+"/"+databaseName;
            Class.forName(driverName).newInstance();
            connection = DriverManager.getConnection(connName,user,password);
            System.out.print("Connect to DB OK...");
            return connection;
      }
      public static java.sql.Connection connectToDb(String databaseName)throws Exception{
            return(connectToDb("localhost", databaseName));
      }
      public static java.sql.Connection connectToDb()throws Exception{
            return(connectToDb("localhost", "addressbook"));
      }
      public static void main(String[] args)throws Exception{
            try{
                  DbUtil db = new DbUtil();
                  db.connectToDb();
            }catch(Exception e){
            e.printStackTrace();
      }
}
}

java.sql.SQLException: Communication link failure: java.io.IOException, underlying cause: Unexpected end of input stream
** BEGIN NESTED EXCEPTION **
java.io.IOException
MESSAGE: Unexpected end of input stream
STACKTRACE:
java.io.IOException: Unexpected end of input stream
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:1096)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:626)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:1562)
at com.mysql.jdbc.Connection.<init>(Connection.java:491)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:346)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at addressbook.model.DbUtil.connectToDb(DbUtil.java:25)
at addressbook.model.DbUtil.connectToDb(DbUtil.java:36)
at addressbook.model.DbUtil.main(DbUtil.java:42)
** END NESTED EXCEPTION **
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:699)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:1562)
at com.mysql.jdbc.Connection.<init>(Connection.java:491)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:346)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at addressbook.model.DbUtil.connectToDb(DbUtil.java:25)
at addressbook.model.DbUtil.connectToDb(DbUtil.java:36)
at addressbook.model.DbUtil.main(DbUtil.java:42)

--转自