模拟用户登录功能

来源：互联网发布：甲骨文 ibm做啥软件编辑：程序博客网时间：2024/05/21 21:43

1.抽取jdbc数据连接类：

DBUtils.java工具类代码如下：

public class DBUtils {
    private static String driverClass;
    private static String url;
    private static String username;
    private static String password;
    static{
       ResourceBundle rb=ResourceBundle.getBundle("dbinfo");
       driverClass=rb.getString("driverClass");
       url=rb.getString("url");
       username=rb.getString("username");
       password=rb.getString("password");
       System.out.println(driverClass+"======="+url+"=============="+username+"-------------"+password);
       try {
           Class.forName(driverClass);
       } catch (ClassNotFoundException e) {
           e.printStackTrace();
       }
    }
    //创建连接
    public static Connection getConnection() throws SQLException{
       return DriverManager.getConnection(url,username,password);
    }
    //关闭资源
    public static void closeAll(ResultSet rs,Statement stmt,Connection conn){
       if(rs!=null){
           try {
               rs.close();
           } catch (SQLException e) {
               e.printStackTrace();
           }
           rs=null;
       }
       if(stmt!=null){
           try {
               stmt.close();
           } catch (SQLException e) {
               e.printStackTrace();
           }
           stmt=null;
       }
       if(conn!=null){
           try {
               conn.close();
           } catch (SQLException e) {
               e.printStackTrace();
           }
           conn=null;
       }
    }
}

2.编写dbinfo.properties文件如下：

driverClass=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/shop
username=root
password=123

3.编写userbean

package com.qq1009108034.entity;

public class User {
   private int id;
   private String username;
   private String password;
   private String email;
   private String birthday;

   public int getId() {
       return id;
   }

   public void setId(int id) {
       this.id = id;
   }

   public String getUsername() {
       return username;
   }

   public void setUsername(String username) {
       this.username = username;
   }

   public String getPassword() {
       return password;
   }

   public void setPassword(String password) {
       this.password = password;
   }

   public String getEmail() {
       return email;
   }

   public void setEmail(String email) {
       this.email = email;
   }

   public String getBirthday() {
       return birthday;
   }

   public void setBirthday(String birthday) {
       this.birthday = birthday;
   }

   @Override
   public String toString() {
       return "User [id=" + id + ", username=" + username + ", password="
               + password + ", email=" + email + ", birthday=" + birthday
               + "]";
   }

}

4.编写数据库操作方法findUser（）代码如下：

public class DoLogin {
   public User findUser(String name,String pwd){
       Connection conn = null;
       PreparedStatement stmt = null;
       ResultSet rs = null;
       User u = null;
       try {
           conn = DBUtils.getConnection();//得到连接对象Connection
           String sql ="SELECT * FROM users WHERE USERNAME=? AND PASSWORD=?";
           stmt = conn.prepareStatement(sql);//得到执行sql语句的对象Statement
           //给？赋值
           stmt.setString(1, name);
           stmt.setString(2, pwd);

           rs = stmt.executeQuery();//执行sql语句
           if(rs.next()){
               u = new User();
               u.setId(rs.getInt(1));
               u.setUsername(rs.getString(2));
               u.setPassword(rs.getString(3));
               u.setEmail(rs.getString(4));

           }
       } catch (SQLException e) {
           e.printStackTrace();
       }finally{
           DBUtils.closeAll(rs, stmt, conn);;
       }

       return u;
   }
}
简单的登录功能实现，其中解决了sql注入问题。

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