userdb.java

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package mypack;
import java.sql.*;
import java.util.*;
import java.lang.*;

public class UserDB {
	 
  String driver="com.microsoft.jdbc.sqlserver.SQLServerDriver";
  String user="sa";
  String pwd="sa";
  String url="jdbc:microsoft:sqlserver://127.0.0.1;databaseName=lm";
  private Connection con;
private Connection getCon() {
	try{
		 Class.forName(driver);
		 Connection con=DriverManager.getConnection(url, user, pwd);
 		return con;
	}catch(Exception e){
		e.printStackTrace();
	}
	return null;
}
  


public UserBean getUser(int  id ){
	try{
		String sql="select * from users where userid="+id;
		Connection con=getCon();
		Statement stm=con.createStatement();
		UserBean user1=null;
		ResultSet rs=stm.executeQuery(sql);
		
		while(rs.next()){
			int userid=rs.getInt(1);
			String username=rs.getString(2);
			String userpassword=rs.getString(3);
			String realaddr=rs.getString(4);
			String realname=rs.getString(5);
			String usertelephone=rs.getString(6);
			String email=rs.getString(7);
			user1=new UserBean(userid,username,userpassword,realaddr,realname,usertelephone,email);
			}
		rs.close();
		stm.close();
		con.close();
		return user1;
	
	}catch(Exception e){
		e.printStackTrace();
	}
	return null;
}

public boolean addUser(UserBean user1){
	try{
		
		   Connection con=getCon();
		   String sql="insert users(username,userpassword,realaddr,realname,usertelephone,email) Values(?,?,?,?,?,?)";//变量
		   PreparedStatement pstm=con.prepareStatement(sql);
		   pstm.setString(1,user1.getUsername());
		   pstm.setString(2,user1.getUserpassword());
		   pstm.setString(3,user1.getRealaddr());
		   pstm.setString(4,user1.getRealname());
		   pstm.setString(5,user1.getUsertelephone());
		   pstm.setString(6,user1.getEmail());
	
		int flg= pstm.executeUpdate();
		pstm.close();
		con.close();
		if(flg!=0){return true;}
	}catch(Exception e){
			e.printStackTrace();
		}
	return false;
}
public boolean delUser(int id){
	try{
		String sql="delete from users where userid="+id;
		Connection con=getCon();
		Statement stm=con.createStatement();
		
		int flg=stm.executeUpdate(sql);
	if(flg!=0){return true;}
	
}catch(Exception e){
	e.printStackTrace();
}
return false;
}
public boolean isexist(String username){
	try{
		String sql="select * from users where username="+username;
		Connection con=getCon();
		Statement stm=con.createStatement();
		ResultSet rs=stm.executeQuery(sql);
		stm.close();
		con.close();
	if(rs.next()){return true;}
	
}catch(Exception e){
	e.printStackTrace();
}
return false;
}
public boolean checkuser(String username,String userpassword){
	try{
		String sql="select * from users where username='"+username+"' and userpassword='"+userpassword+"'";		
		Connection con=getCon();
		Statement stm=con.createStatement();
		ResultSet rs=stm.executeQuery(sql);
		stm.close();
		con.close();
	if(rs.next()){return true;}
	
}catch(Exception e){
	e.printStackTrace();
}
return false;
	
}
public int getuserid(String username){
	int userid=0;
	try{
		String sql="select userid from users where username='"+username+"' ";		
		Connection con=getCon();
		Statement stm=con.createStatement();
		ResultSet rs=stm.executeQuery(sql);
		stm.close();
		con.close();
		if(rs.next()){  userid=rs.getInt(1);
				return userid;
		}
	}catch(Exception e){
		e.printStackTrace();
	}
	return userid;
}

}