package com.jdbc.connection;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Scanner;public class UserLonginClass
{
static Connection con = null;
static Statement stm = null;
static String userName = "sa";
static String userpassWord = "java";
public static void Connection()
{
String URL = "jdbc:sqlserver://localhost:1433;DatabaseName=haifei";
try
{
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
con = DriverManager.getConnection(URL,userName,userpassWord);
}
catch(Exception e1)
{
e1.printStackTrace();
}
}
public static int execteUpdate(String sql)
{
try
{
return stm.executeUpdate(sql);
}
catch(Exception e)
{
e.printStackTrace();
return 0;
}
}
public static void Loigin()
{
String Name = null;
String Password = null;
Scanner scan = new Scanner(System.in);
while(true)
{
System.out.println("plese enter userName");
Name = scan.next();
if (Name.equals("quit"))
{
return;
}
System.out.println("plese enter userPassword");
Password = scan.next();
if(Password.equals("quit"))
{
return;
}
UserLonginClass.execteUpdate("insert into [haifei].[dbo].[userLoginName3] values (Name,Password)");
}
}
public static void statement()throws Exception
{
String st = "select * from [haifei].[dbo].[userLoginName3]";
ResultSet s = stm.executeQuery(st);
while (s.next())
{
String name = s.getString("iname");
String password = s.getString("iPassword");
System.out.print(name + " " + password);
}
System.out.println();
}
public static void main(String args[])throws Exception
{
UserLonginClass. Connection();
UserLonginClass.Loigin();
UserLonginClass.statement();
}
}
运行的时候会出现这样的问异常
java.lang.NullPointerException
at com.jdbc.connection.UserLonginClass.execteUpdate(UserLonginClass.java:38)
at com.jdbc.connection.UserLonginClass.Loigin(UserLonginClass.java:73)
at com.jdbc.connection.UserLonginClass.main(UserLonginClass.java:98)
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Scanner;public class UserLonginClass
{
static Connection con = null;
static Statement stm = null;
static String userName = "sa";
static String userpassWord = "java";
public static void Connection()
{
String URL = "jdbc:sqlserver://localhost:1433;DatabaseName=haifei";
try
{
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
con = DriverManager.getConnection(URL,userName,userpassWord);
}
catch(Exception e1)
{
e1.printStackTrace();
}
}
public static int execteUpdate(String sql)
{
try
{
return stm.executeUpdate(sql);
}
catch(Exception e)
{
e.printStackTrace();
return 0;
}
}
public static void Loigin()
{
String Name = null;
String Password = null;
Scanner scan = new Scanner(System.in);
while(true)
{
System.out.println("plese enter userName");
Name = scan.next();
if (Name.equals("quit"))
{
return;
}
System.out.println("plese enter userPassword");
Password = scan.next();
if(Password.equals("quit"))
{
return;
}
UserLonginClass.execteUpdate("insert into [haifei].[dbo].[userLoginName3] values (Name,Password)");
}
}
public static void statement()throws Exception
{
String st = "select * from [haifei].[dbo].[userLoginName3]";
ResultSet s = stm.executeQuery(st);
while (s.next())
{
String name = s.getString("iname");
String password = s.getString("iPassword");
System.out.print(name + " " + password);
}
System.out.println();
}
public static void main(String args[])throws Exception
{
UserLonginClass. Connection();
UserLonginClass.Loigin();
UserLonginClass.statement();
}
}
运行的时候会出现这样的问异常
java.lang.NullPointerException
at com.jdbc.connection.UserLonginClass.execteUpdate(UserLonginClass.java:38)
at com.jdbc.connection.UserLonginClass.Loigin(UserLonginClass.java:73)
at com.jdbc.connection.UserLonginClass.main(UserLonginClass.java:98)
我自己的一点意见把那个SQL语句换成 insert into [][][] values ( " + "'"+Name+"'"+","+"'"+Password+"'"+")";