2021-11-04

2021/11/5 6:13:47

编程Tag： string import 11 public 2021 04 sname cid spwd

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用servlet连接数据库实现登陆验证

<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>
<form action="login" method="post">
<table>
账号:<input type="text" name="sname" value="张三">
密码:<input type="password" name="spwd" value="123">
<input type="submit" value="登录">
</table>
</form>
</body>
</html>

public interface Dao {

Student login(String sname, String spwd);

}

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DaoImpl implements Dao{

   @Override
   public Student login(String sname, String spwd) {
       Student student = null;
       Util u = new Util();
       Connection conn = u.getConn();
       try {
           PreparedStatement ps = conn.prepareStatement("select * from student where sname=? and spwd=?");
           ps.setString(1,sname);
           ps.setString(2, spwd);
           ResultSet rs =ps.executeQuery();
           while(rs.next()) {
               int sid = rs.getInt("sid");
               int cid = rs.getInt("cid");
               student = new Student(sid, sname, spwd, cid);
           }
       } catch (SQLException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

       return student;
   }

}

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* Servlet implementation class Servlet
*/
@WebServlet("/login")
public class Servlet extends HttpServlet {

   protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
       // TODO Auto-generated method stub

doPost(request, response);
}

   /**
   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
   */
   protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
       // TODO Auto-generated method stub

       request.setCharacterEncoding("utf-8");
       String sname = request.getParameter("sname");
       String spwd = request.getParameter("spwd");
       System.out.println(sname+""+spwd);

       Dao d = new DaoImpl();
       Student s = d.login(sname,spwd);
       if (s!=null) {
           System.out.println("登陆成功");
       }else {
           System.out.println("登陆失败");
       }
   }

}

public class Student {
private int sid;
private String sname;
private String spwd;
private int cid;

public int getSid() {
return sid;
}

public void setSid(int sid) {
this.sid = sid;
}

public String getSname() {
return sname;
}

public void setSname(String sname) {
this.sname = sname;
}

public String getSpwd() {
return spwd;
}

public void setSpwd(String spwd) {
this.spwd = spwd;
}

public int getCid() {
return cid;
}

public void setCid(int cid) {
this.cid = cid;
}

public Student(int sid, String sname, String spwd, int cid) {
this.sid = sid;
this.sname = sname;
this.spwd = spwd;
this.cid = cid;
}
}

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class Util {
private static String URL = "jdbc:mysql://localhost:3306/mydb";
private static String NAME = "root";
private static String PWD = "123456";

private static Connection conn;

public static Connection getConn(){
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(URL,NAME,PWD);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e){
e.printStackTrace();
}
return conn;
}

public void close(Connection conn){
if(conn!=null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

// public static void main(String[] args) {
// System.out.println(getConn());
// }

}

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2021-11-04

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