dbcon.java

JAVA编写的登陆窗体

package loginexample;

import java.sql.*;

/**
 * <p>Title: </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2007</p>
 *
 * <p>Company: </p>
 *
 * @author not attributable
 * @version 1.0
 */
public class DBCON {
    public DBCON() {
        try {
            Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
        } catch (ClassNotFoundException ex) {
            ex.printStackTrace();
        }
    }

    public boolean updateuser(String newpass, String name, String oldpass) {
        String url =
                "jdbc:microsoft:sqlserver://127.0.0.1:1433;databasename=bb1";
        Connection con = null;
        PreparedStatement ps = null;

        try {
            con = DriverManager.getConnection(url, "sa", "");
            ps = con.prepareStatement(
                    "update userinfo set userpass=? where username=? and userpass=?");
            ps.setString(1, newpass);
            ps.setString(2, name);
            ps.setString(3, oldpass);
            int row = ps.executeUpdate();
            if (row > 0) {

                return true;
            }
        } catch (SQLException ex) {
            ex.printStackTrace();
        } finally {
            if (ps != null) {
                try {
                    ps.close();
                } catch (SQLException ex1) {
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException ex2) {
                }
            }
        }
        return false; //给函数名赋值updateuser=false;
    }

    String password; //密码属性
    public boolean selectusername(String aaa) {
        String url =
                "jdbc:microsoft:sqlserver://127.0.0.1:1433;databasename=bb1";
        Connection con = null;
        PreparedStatement ps = null;
        try {
            con = DriverManager.getConnection(url, "sa", "");
            ps = con.prepareStatement("select * from userinfo where username=?"); //预处理sql语句,可以预留 参数用?来站位
            //设置参数第一个?(问号)即为第一个参数,用set<类型>的方式给?(问号)赋值
            ps.setString(1, aaa); //1:表示第一个问号(?) name:表示?(问号)的值
            //
            ResultSet rs = ps.executeQuery();
            if (rs.next()) {
                //如果有这个用户,就从数据库中取出他的原密码放到password这个属性中
                password = rs.getString(3);

                return true;
            }
        } catch (SQLException ex) {
            ex.printStackTrace();
        } finally {
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException ex1) {
                }
            }
        }
        return false;
    }

    public boolean selectuser(String name, String pass) //name=str=jTextField1.getText.trim()
    //pass=strpass=jPasswordFeild.getPassword();
    {
        String url =
                "jdbc:microsoft:sqlserver://127.0.0.1:1433;databasename=bb1";
        Connection con = null; //用来连接数据库
        PreparedStatement ps = null; //用来执行sql语句

        try {
            con = DriverManager.getConnection(url, "sa", "");
            ps = con.prepareStatement(
                    "select * from userinfo where username=? and userpass=?");
//            ps.setString(1,jTextField.getText.trim());
            //          ps.setString(2,"123");
            ps.setString(1, name);
            ps.setString(2, pass);
            ResultSet rs = ps.executeQuery(); //执行sql中的select语句的
            if (rs.next()) {
                return true;
            }
            //select语句的结果类型是===〉记录集==〉ResultSet
        } catch (SQLException ex) {
            ex.printStackTrace();
        } finally {

        }

        return false;
    }
    public boolean insertuser(String name,String mima)
    {
        String url="jdbc:microsoft:sqlserver://127.0.0.1:1433;databasename=bb1";
        Connection con=null;
        PreparedStatement ps=null;

        try {
            con = DriverManager.getConnection(url, "sa", "");
            ps=con.prepareStatement("insert into userinfo values(?,?)");
            ps.setString(1,name);
            ps.setString(2,mima);
          int row=  ps.executeUpdate();
          if(row>0)
          {
              return true;
          }
        } catch (SQLException ex) {
            ex.printStackTrace();
        }
        finally
        {
            if(con!=null)
            {
                try {
                    con.close();
                } catch (SQLException ex1) {
                }
            }
        }
        return false;
    }
    public static void main(String args[]) {
        DBCON db = new DBCON();
        // db.selectuser("aa", "123");
        db.selectusername("aaa");
    }

}