数据库连接与用户登录

来源：互联网发布：淘宝如何避免盗图投诉编辑：程序博客网时间：2024/06/06 19:14

1.数据库连接

利用myEclipse与mysql进行连接

从官网上下载jar包，导入到myEclipse中，接下来书写相关的连接代码：

代码如下：

package com.iotek.dao.impl;

import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import javax.naming.spi.DirStateFactory.Result;

public class BassDao {
       //private static final String DRIVER="com.mysql.jdbc";

       public Connection getConn(){
        Connection conn=null;
        try{
         Class.forName("com.mysql.jdbc.Driver");
        }catch(ClassNotFoundException e){
        e.printStackTrace();
        }
        try {
   conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/data","root","123456");
  } catch (SQLException e) {
   e.printStackTrace();
  }
        return conn;
       }
       /**
        * 释放相应的资源
        * @param rs
        * @param pstmt
        * @param conn
        */
       public void closeAll(ResultSet rs,PreparedStatement pstmt,Connection conn){
              try{
               if(rs!=null){
                   rs.close();
                }
               if(pstmt!=null){
                   pstmt.close();
                }
               if(conn!=null){
                conn.close();
               }
              }catch(SQLException e){
               e.printStackTrace();
              }
       }
       /**
        * 此方法可以完成增删改所有操作
        * @param sql
        * @param params
        * @return true 或 false
        */
       public boolean operUpdate(String sql,List<Object>params){
        int res=0;//影响的行数
        Connection conn=null;
        PreparedStatement pstmt=null;
        ResultSet rs=null;
        try {
   conn=getConn();//建立数据库连接
   pstmt=conn.prepareStatement(sql);//装载数据库语句
      if(params!=null){
      //假如有？，在执行前把？占位符替换掉
      for(int i=0;i<params.size();i++){
        pstmt.setObject(i+1, params.get(i));
      }
      }
      res=pstmt.executeUpdate();
        } catch (SQLException e) {
   e.printStackTrace();
     }finally{
      closeAll(rs,pstmt,conn);
     }
        return res>0? true : false;
       }
       /**
        * 使用泛型方法和反射机制进行封装,数据的查询
        * @param sql
        * @param params
        * @param cls
        * @return
        */
       public <T> List<T> operQuery(String sql,List<Object>params,Class<T> cls)throws Exception{
        Connection conn=null;
        PreparedStatement pstmt=null;
        ResultSet rs=null;
        List<T> data=new ArrayList<T>();
        try {
      conn=getConn();//建立数据库连接
      pstmt=conn.prepareStatement(sql);//装载sql语句
         if(params!=null){
         //假如有？，在执行前把？占位符替换掉
         for(int i=0;i<params.size();i++){
           pstmt.setObject(i+1, params.get(i));
         }
         }
         rs=pstmt.executeQuery();
         //把查询出来的记录封装成对应的实体类对象
         ResultSetMetaData rsd=rs.getMetaData();
         while(rs.next()){
         T m =cls.newInstance();
         for(int i=0;i<rsd.getColumnCount();i++){
           String col_name=rsd.getColumnName(i+1);//获得列名
           Object value=rs.getObject(col_name);//获得列所对应的值
           Field field=cls.getDeclaredField(col_name);
           field.setAccessible(true);//给私有属性设置可访问权限
           field.set(m, value);//给对象的私有属性赋值
         }
         data.add(m);
         }
           } catch (SQLException e) {
      e.printStackTrace();
        }finally{
         closeAll(rs,pstmt,conn);
        }
        return data;
       }
}

具体作用代码中有详解。

2.数据库设计：

建立3张表

1）.users表，列为：id（用户编号）；uname（用户名）；upass（用户密码）；type（用户类型）。

2）.dvds表，列为：ID（dvd编号）；dname（dvd名字）；dcount（借出次数）；status（dvd状态）。

3）.records表，列为：ID（记录编号）；uid（借dvd人的编号）；did（所借dvd的编号）；lendtime（接出时间）；returntime（归还时间）。

3.用户登录

先写关于users表的相关操作：

package com.iotek.entity;

public class Users {
    private int id;
    private String uname;
    private String upass;
    private int type;
    public Users(){

    }
public Users(String uname, String upass, int type) {
  super();
  this.uname = uname;
  this.upass = upass;
  this.type = type;
}
public Users(int id, String uname, String upass, int type) {
  super();
  this.id = id;
  this.uname = uname;
  this.upass = upass;
  this.type = type;
}

public int getId() {
  return id;
}
public void setId(int id) {
  this.id = id;
}
public String getUname() {
  return uname;
}
public void setUname(String uname) {
  this.uname = uname;
}
public String getUpass() {
  return upass;
}
public void setUpass(String upass) {
  this.upass = upass;
}
public int getType() {
  return type;
}
public void setType(int type) {
  this.type = type;
}

}

package com.iotek.dao;

import com.iotek.entity.*;

public interface UserDao {
public boolean saveUser(Users user);
public boolean delUser(int id);
public boolean updateUser(Users user);
public Users queryUser(Users user);

}

package com.iotek.dao.impl;

import java.util.ArrayList;
import java.util.List;

import com.iotek.dao.UserDao;
import com.iotek.entity.Users;

public class UserDaoImpl extends BassDao implements UserDao {

@Override
public boolean saveUser(Users user) {
  String sql="insert into users(uname,upass,type) values(?,?,?)";
  List<Object> params=new ArrayList<Object>();
  params.add(user.getUname());
  params.add(user.getUpass());
  params.add(user.getType());
  return this.operUpdate(sql, params);
}

@Override
public boolean delUser(int id) {
  String sql="delete from users where id=?";
  List<Object> params=new ArrayList<Object>();
  params.add(id);
  return this.operUpdate(sql, params);
}

@Override
public boolean updateUser(Users user) {
  String sql="update users set uname=?,upass=?,type=? where id=?";
  List<Object> params=new ArrayList<Object>();
  params.add(user.getUname());
  params.add(user.getUpass());
  params.add(user.getType());
  params.add(user.getId());
  return this.operUpdate(sql, params);
}

@Override
public Users queryUser(Users user) {
  List<Users> uList=null;
  String sql="select id,uname,upass,type from users where uname=? and upass=? and type=?";
  List<Object> params=new ArrayList<Object>();
  params.add(user.getUname());
  params.add(user.getUpass());
  params.add(user.getType());
  try {
   uList=this.operQuery(sql, params,Users.class);
  } catch (Exception e) {
   e.printStackTrace();
  }
  if(uList.size()>0){
   return uList.get(0);
  }
  return null;
}

}

接下来进行用户登录的书写：

代码如下：

package com.iotek.view;

import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.ImageObserver;
import java.awt.image.ImageProducer;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

import com.iotek.biz.UserBiz;
import com.iotek.biz.impl.UserBizImpl;
import com.iotek.entity.Users;

public class LoginView extends JFrame {
private JPanel panel_main= null;
private JPanel panel_left=null;
private JPanel panel_right=null;

private JLabel lb_uname=null;
private JLabel lb_upass=null;
private JLabel lb_type=null;

private JTextField tf_uname=null;
private JPasswordField pf_pass=null;

private JLabel lb_img=null;

private JButton btn_login=null;
private JButton btn_register=null;

private JComboBox cb_type=null;

    private UserBiz userBiz=null;

public LoginView(){
  userBiz=new UserBizImpl();
  init();
  registerListener();
}

private void init(){
  this.setSize(320, 220);
  this.setResizable(false);
  this.setLocationRelativeTo(null);
  this.setTitle("登录窗口");
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


  panel_main=new JPanel(new GridLayout(1, 2));
  panel_left=new JPanel();
  panel_right=new JPanel(new GridLayout(4, 2,0,10));


  tf_uname=new JTextField(8);
  pf_pass=new JPasswordField(8);
     cb_type=new JComboBox();
     cb_type.addItem("普通用户");
     cb_type.addItem("管理员");
     btn_login=new JButton("登录");
     btn_register=new JButton("注册") ;
     lb_uname=new JLabel("用户名：",JLabel.CENTER);
     lb_upass=new JLabel("密码：",JLabel.CENTER);
     lb_type=new JLabel("类型：",JLabel.CENTER);
     lb_img=new JLabel(new ImageIcon(ClassLoader.getSystemResource("1.jpg")));


     panel_left.add(lb_img);
     panel_right.add(lb_uname);
     panel_right.add(tf_uname);
     panel_right.add(lb_upass);
     panel_right.add(pf_pass);
     panel_right.add(lb_type);
     panel_right.add(cb_type);
     panel_right.add(btn_login);
     panel_right.add(btn_register);


     panel_main.add(panel_left);
     panel_main.add(panel_right);


     this.getContentPane().add(panel_main);
     this.pack();
  this.setVisible(true);

}

private void registerListener(){
  btn_register.addActionListener(new ActionListener() {

   @Override
   public void actionPerformed(ActionEvent e) {
    new UserRegisterView();

   }
  });
  btn_login.addActionListener(new ActionListener() {

   @Override
   public void actionPerformed(ActionEvent e) {

    String sname=tf_uname.getText().trim();
    String spass=new String(pf_pass.getPassword());
    int type=cb_type.getSelectedIndex()+1;
    if(sname.equals("")){
     JOptionPane.showMessageDialog(LoginView.this, "用户名不能为空");
        return;
    }else if(spass.equals("")){
     JOptionPane.showMessageDialog(LoginView.this, "密码不能为空");
        return;
    }
    Users user=new Users(sname,spass, type);
    user=userBiz.login(user);
    if(user!=null){
     if(user.getType()==1){
      new UserMainView(user);
     }else{
      new AdminMainView(user);
     }
     LoginView.this.dispose();
    }
    else{
     JOptionPane.showMessageDialog(LoginView.this, "用户名或密码出错");
        return;
    }
   }
  });
}

}

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