Servlet登录二-带数据库

class Dao { public static Connection getConnection() { try { Class.forName("com.mysql.jdbc.Driver"); String url ="jdbc:mysql://localhost:3306/JavaWeb?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPublicKeyRetrieval=true"; Connection con=(Connection) DriverManager.getConnection(url, "root", "AQCTBQLYxingye1."); return con; } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); return null; } } public static void Insertdata(List<Person> l) throws SQLException { Connection con= getConnection(); Statement stat = (Statement) con.createStatement(); stat.executeUpdate("delete from user"); for(Person p:l) { String str= "insert into user values(‘"+p.getZh()+"‘,‘"+p.getMm()+"‘)"; System.out.println(str); stat.executeUpdate(str); } stat.close(); con.close(); } public static List<Person> Selectdata(String param) throws SQLException { List<Person> list=new ArrayList<>(); Connection con= getConnection(); Statement stat = (Statement) con.createStatement(); String sql="select *from user"; sql+=" where zh=‘"+param+"‘"; ResultSet result = stat.executeQuery(sql); list.clear(); while (result.next()) { Person p=new Person(result.getString("zh"),result.getString("mm")); list.add(p); } stat.close(); con.close(); return list; } } Dao.java

3.在LoginServlet中的 init 初始化函数中加入了数据初始化 ，添加了两个用户进入数据库

public class LoginServlet extends HttpServlet {

    @Override
    public void init() throws ServletException {
        // TODO Auto-generated method stub
        super.init();
        List<Person> l=new ArrayList<>();
        Person p=new Person("root","admin");
        l.add(p);
        p=new Person("123","123");
        l.add(p);
        try {
            Dao.Insertdata(l);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // TODO Auto-generated method stub
        String zh=req.getParameter("zh");
        String mm=req.getParameter("mm");
        String info=null;
        try {
            List<Person> l=Dao.Selectdata(zh);
            if(l.size()==0) {
                    info="该用户不存在";
            }
            else {
                if(l.get(0).getMm().equals(mm)) {
                    info="登录成功:账号"+zh+"  -密码:"+mm;
                }
                else {
                    info="密码错误";
                }
            }
            
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            info=e.getMessage();
            
        }
        req.getSession(true).setAttribute("info",info);
        resp.sendRedirect(req.getContextPath()+"/"+"info.jsp");
        
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(req, resp);
    }

    
}

LoginServlet.java

项目其他源码参考 Servlet登录

 

百度云下载链接

链接：https://pan.baidu.com/s/1yyoCAWcwvq_c2kO84Kpo0A
提取码：mhe0

Servlet登录二-带数据库

标签：alt   add   文件   gif   str   select   static   admin   from