Web作業——學生體質信息管理（DAO設計模式）

原創 '友人A' 2020-06-03 19:32

數據庫：student 表：user
表格結構：
在這裏插入圖片描述

DAO，數據訪問對象，主要的功能就是數據操作，在標準的程序開發架構中屬於數據層的操作。其主要分爲以下幾層：

客戶層：因爲現在大多采用B/S架構，所以一般客戶都是用瀏覽器進行訪問，當然也可以使用其它的訪問程序。

顯示層：使用JSP/Servlet進行頁面效果的顯示。

業務層：會將多個原子性的DAO操作進行組合，組成一個完整的業務邏輯。

數據層(DAO)：提供原子性的操作，例如增刪改查等。

DAO設計流程：

1設計一個專門負責打開連接數據庫和關閉數據庫操作的類。命名規則：xxx.dbc.DatabaseConnection

2設計VO（值對象）,其主要有屬性和setter和getter方法構成，以數據庫中的字段項對應。命名規則：xxx.vo.ttt；ttt要與數據庫的表的名字一致

3.DAO設計：定義一系列的原子性操作，如增刪改查等操作的接口。命名規則：xxx.dao.IXxx.DAO

4設計DAO接口的真正實現的類，完成具體的數據庫操作。但是不再去負責數據庫的打開和關閉。命名規則：xxx.dao.impl.xxxDAOImpl

5.proxy代理類的實現：主要將1，4結合起來，完成整個操作過程。命名規則：xxx.dao.proxy.XxxProxy

6.Factory類主要用來獲得一個DAO類的實例對象。命名規則：xxx.factory.DAOFactory
引用

我寫的DAO並不是真正的DAO設計模式，因爲我沒有添加代理類來解耦數據庫連接與數據庫操作，也沒有加工廠模式類返回代理類的對象。但是基本的框架還是有的。
如有錯誤，請指出，謝謝！

首先先列出基本的框架，分別有三個包，bean包，DAO包，Servlets包。DAO包下的Student.javaStudent.java爲數據庫對象類，一個對象代表着數據庫中的一個記錄，我認真把它放在beans包下比較好，但也懶得改了。
在這裏插入圖片描述

文章目錄

JSP

index.html(主頁面)

利用frameset框架來設計網頁佈局
在這裏插入圖片描述


<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<frameset rows="15%,*">
	<frame src = "title.html" noresize=“noresize”>
	<frameset cols="10%,*">
		<frame src="lable.html" noresize=“noresize”>
		<frame src="display.html" name="view_frame" noresize=“noresize”>
	</frameset>

</frameset>
</html>

title.html(標題頁面)

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<style>
h1{
	text-align:center;
	color:#CD5C5C;
	font-family:"宋體";
}
body{
	background-color:#F0F8FF;
}
</style>
<body>	
	<img src="http://img.sccnn.com/simg/338/64538.jpg" style="float:left" width="60" height="50">
	<h1>
		學生體質信息管理
	</h1>
</body>
</html>

lable.html(目錄頁面)

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<h3>目錄</h3>
	<ul>
		<li><a href="Studentall" target="view_frame">主頁</a></li>
		<li><a href="AddStudent.jsp" target="view_frame">添加</a></li>
		<li><a href="find.jsp" target="view_frame">查找</a></li>
		<li><a href="update.jsp" target="view_frame">更新</a></li>
		<li><a href="delete.jsp" target="view_frame">刪除</a></li>
	</ul>

</body>
</html>

display.html(初始頁面)

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<div align="center">
	<h1>
		歡迎使用學生體質信息管理系統
	</h1>
</div>
</body>
</html>

showall.jsp(顯示所有記錄)

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8" import = "java.util.*"%>
<%@ page import = "DAO.Student" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style>
	body {
		padding: 40px 100px;
	}
	table {
		*border-collapse: collapse; /* IE7 and lower */
		border-spacing: 0;
		width: 100%;
	}
</style>
</head>
<body>
<div align="center">
	<%
		//int cnt = 1;
		List<Student> list = (List<Student>)request.getAttribute("list");
		if(list == null||list.size()==0){
	%>
			<h3>無記錄</h3>
	<%
		}
		else{
	%>
	<table border="1">
	<br><br><br><br>
	<tr>
		<th>編號</th>
		<th>姓名</th>
		<th>性別</th>
		<th>年齡</th>
		<th>身高</th>
		<th>體重</th>
	</tr>
	<%
			for(Student st:list){
	%>
			<tr>
				<td><%=st.getId()%></td>
				<td><%=st.getName() %></td>
				<td><%=st.getSex() %>
				<td><%=st.getAge() %></td>
				<td><%=st.getHeight() %></td>
				<td><%=st.getWeight() %></td>
			</tr>
	<%
			}
		}
	%>
	</table>
</div>
</body>
</html>

showFind.jsp(顯示模糊查找結果頁面)

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8" import = "java.util.*"%>
<%@ page import = "DAO.Student" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style>
	body {
		padding: 40px 100px;
	}
	table {
		*border-collapse: collapse; /* IE7 and lower */
		border-spacing: 0;
		width: 100%;
	}
</style>
</head>
<body>
<div align="center">
	<%
		List<Student> list = (List<Student>)request.getAttribute("list");
		if(list == null||list.size()==0){
	%>
			<h3>無記錄</h3>
	<%
		}
		else{
	%>
	<table border="1">
	<br><br><br><br>
	<tr>
		<th>姓名</th>
		<th>性別</th>
		<th>年齡</th>
		<th>身高</th>
		<th>體重</th>
	</tr>
	<%
			for(Student st:list){
	%>
			<tr>
				<td><%=st.getName() %></td>
				<td><%=st.getSex() %>
				<td><%=st.getAge() %></td>
				<td><%=st.getHeight() %></td>
				<td><%=st.getWeight() %></td>
			</tr>
	<%
			}
		}
	%>
	</table>
</div>
</body>
</html>

AddStudent.jsp(添加頁面)

<%@ 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>
</style>
</head>
<body>
<div align="center">
	<br>
	<h3>添加記錄</h3>
	<form action="AddStudent" method="post">
		<table  border="0" cellpadding="10" cellspacing="0">
			<tr>
				<th>姓名</th>
				<td><input name="t_name"></td>
			</tr>
			<tr>
				<th>性別</th>
				<td><input name="t_sex"></td>
			</tr>
			<tr>
				<th>年齡</th>
				<td><input name="t_age"></td>
			</tr>
			<tr>
				<th>身高</th>
				<td><input name="t_height"></td>
			</tr>
			<tr>
				<th>體重</th>
				<td><input name="t_weight"></td>
			</tr>
			<tr>
				<th><input type="submit" value="提交"></th>
				<th><input type="reset" value="重置"></th>
			</tr>

		</table>
		
	</form>
</div>
</body>
</html>

addsuccess.jsp(添加成功頁面)

<%@ 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>
	<b>添加成功！</b>
</body>
</html>

addfail.jsp(添加失敗頁面)

<%@ 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>
	<b>添加失敗！</b>
</body>
</html>

find.jsp(查找頁面)

<%@ 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>
<div align="center">
	<h3>模糊查找</h3>
	<form action="StudentFind" method="post">
	請輸入帶查找學生的名字或部分名字: <input name="t_name">
	<br>
	<br>
	<input type="submit" value="查找">
	</form>
	
</div>
</body>
</html>

delete.jsp(刪除頁面)

<%@ 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>
<div align="center">
	<h3>學生信息刪除</h3>
	<form action="StudentDelete" action="post">
	請輸入待刪除的學生編號:<input name="t_id"><br><br>
	<input type="submit" value="刪除">
	</form>
</div>
</body>
</html>

update.jsp(更新頁面)

<%@ 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>
<div align="center">
	<h3>學生信息更新</h3>
	<form action="Studentupdate" action="post">
	請輸入待更新的學生編號:<input name="t_id"><br><br>
	<input type="submit" value="更新">
	</form>
</div>
</body>
</html>

updateEditor.jsp(更新編輯頁面)

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8" import="DAO.Student"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</style>
</head>
<body>
	<%
		request.setCharacterEncoding("utf-8");
		Student stu = (Student)request.getAttribute("stu");
		String id = (String)request.getAttribute("id");
		
	%>
<div align="center">
	<br>
	<h3>更新記錄</h3>
	<form action="Studentupdate2" method="post">
		<table  border="0" cellpadding="10" cellspacing="0">
			<tr>
				<th>姓名</th>
				<td><input name="t_name" value="<%=stu.getName()%>"></td>
			</tr>
			<tr>
				<th>性別</th>
				<td><input name="t_sex" value="<%=stu.getSex()%>"></td>
			</tr>
			<tr>
				<th>年齡</th>
				<td><input name="t_age" value="<%=stu.getAge()%>"></td>
			</tr>
			<tr>
				<th>身高</th>
				<td><input name="t_height" value="<%=stu.getHeight()%>"></td>
			</tr>
			<tr>
				<th>體重</th>
				<td><input name="t_weight" value="<%=stu.getWeight()%>"></td>
			</tr>
			<tr>
				<th><input type="submit" value="更改"></th>
				<th><input type="reset" value="重置"></th>
			</tr>
			<tr>
				<td><input type="hidden" value="<%=id%>" name="id"></input></td>
			</tr>
			

		</table>
		
	</form>
</div>
</body>
</html>

java

beans.JDBCUtils.java(數據庫連接工具類)

package beans;

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

public class JDBCUtils {
//這個工具類,主要爲我們獲取一個數據庫連接
	private static String driverName = "com.mysql.jdbc.Driver";
	private static String url = "jdbc:mysql://localhost:3306/student?useUnicode=true&characterEncoding=UTF8";
	private static String username = "root";
	private static String password = "123456";

//靜態代碼塊,目的,讓第一次使用到JDBCUtils中加載驅動,第二次以後不再加載了
	static {
//1.加載驅動
		try {
			Class.forName(driverName);
		} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
//System.out.println("驅動加載失敗..請檢查驅動包");
			throw new RuntimeException("驅動加載失敗..請檢查驅動包");
		}
	}

	public static Connection getConnection() throws Exception {
//2.獲取和數據庫的連接
		Connection conn = DriverManager.getConnection(url, username, password);
//3.返回連接對象
		return conn;

	}

//關閉所有資源的統一代碼
	public static void closeAll(Connection conn, Statement st, ResultSet rs) {
//負責關閉
		if (conn != null) {
			try {
				conn.close();
			} catch (SQLException e) {
// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if (st != null) {
			try {
				st.close();
			} catch (SQLException e) {
// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if (rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {
// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
}

DAO.IStudentDAO.java(DAO接口)

package DAO;

import java.util.List;

public interface IStudentDAO {
	int create(Student stu) throws Exception;
	void remove(String id) throws Exception;
	List<Student> find(String x) throws Exception;
	List<Student> findall() throws Exception;
	void update(Student stu,String id) throws Exception;
}

DAO.Student.java(數據庫對象類)

package DAO;

public class Student {
	private int id;
	private String name;
	private int age;
	private String sex;
	private float height,weight;
	public Student(){
		
	}
	public Student(int id,String name,int age,String sex,float height,float weight) {
		this.id = id;this.name = name ;this.age = age;this.sex = sex;this.height = height;this.weight = weight;
	}
	public Student(String name,int age,String sex,float height,float weight) {
		this.name = name ;this.age = age;this.sex = sex;this.height = height;this.weight = weight;
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
	public float getHeight() {
		return height;
	}
	public void setHeight(float height) {
		this.height = height;
	}
	public float getWeight() {
		return weight;
	}
	public void setWeight(float weight) {
		this.weight = weight;
	}
	
}

DAO.StudentDAO.java(DAO接口實現類)

package DAO;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.LinkedList;
import java.util.List;

import beans.JDBCUtils;

public class StudentDAO implements IStudentDAO{

	@Override
	public int create(Student stu) throws Exception {
		// TODO Auto-generated method stub
		Connection con = JDBCUtils.getConnection();
		String sql = "insert into user(name,age,sex,height,weight) values(?,?,?,?,?)";
		PreparedStatement pst = con.prepareStatement(sql);
		pst.setString(1, stu.getName());
		pst.setInt(2, stu.getAge());
		pst.setString(3, stu.getSex());
		pst.setFloat(4, stu.getHeight());
		pst.setFloat(5,stu.getWeight());
		int n = pst.executeUpdate();
		return n;
	}

	@Override
	public void remove(String id) throws Exception {
		// TODO Auto-generated method stub
		Connection con = JDBCUtils.getConnection();
		Statement smt = con.createStatement();
		//System.out.println(id);
		String sql = "delete from user where id = " + id;
		smt.executeUpdate(sql);
	}

	@Override
	public List<Student> find(String x) throws Exception {
		// TODO Auto-generated method stub
		List<Student> list = new LinkedList<Student>();
		Connection con = JDBCUtils.getConnection();
		String sql = "select * from user where name like \"%\"?\"%\"";
		PreparedStatement pst = con.prepareStatement(sql);
		pst.setString(1, x);
		ResultSet rs = pst.executeQuery();
		while(rs.next()) {
			list.add(new Student(rs.getString(2),rs.getInt(3),rs.getString(4),rs.getFloat(5),rs.getFloat(6)));
		}
		return list;
	}

	@Override
	public List<Student> findall() throws Exception{
		// TODO Auto-generated method stub
		List<Student> list = new LinkedList<Student>();
		Connection con = JDBCUtils.getConnection();
		String sql = "select * from user";
		Statement smt = con.createStatement();
		ResultSet rs = smt.executeQuery(sql);
		while(rs.next()) {
			list.add(new Student(rs.getInt(1),rs.getString(2),rs.getInt(3),rs.getString(4),rs.getFloat(5),rs.getFloat(6)));
		}
		return list;
	}

	@Override
	public void update(Student stu,String id) throws Exception {
		Connection con = JDBCUtils.getConnection();
		String sql = "update user set name = ? ,age = ? ,sex = ? ,height = ?,weight = ? where id = " + id;
		PreparedStatement pst  = con.prepareStatement(sql);
		pst.setString(1, stu.getName());
		pst.setInt(2, stu.getAge());
		pst.setString(3, stu.getSex());
		pst.setFloat(4, stu.getHeight());
		pst.setFloat(5, stu.getWeight());
		pst.executeUpdate();
	}

}

Servlets.AddStudent.java(控制學生記錄添加的Servlet)

package Servlets;

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;

import DAO.Student;
import DAO.StudentDAO;

/**
 * Servlet implementation class AddStudent
 */
@WebServlet("/AddStudent")
public class AddStudent extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public AddStudent() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub 
		request.setCharacterEncoding("utf-8");
		String name = request.getParameter("t_name");
		int  age = Integer.parseInt(request.getParameter("t_age"));
		String sex = request.getParameter("t_sex");
		float height = Float.parseFloat(request.getParameter("t_height"));
		float weight = Float.parseFloat(request.getParameter("t_weight"));
		StudentDAO std = new StudentDAO();
		int n  = 0;
		try {
			n = std.create(new Student(name,age,sex,height,weight));
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		if(n == 0) request.getRequestDispatcher("addfail.jsp").forward(request, response);
		else request.getRequestDispatcher("addsuccess.jsp").forward(request, response);
	}

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

}

Servlets.Studentall.java(控制信息展示的Servlet)

package Servlets;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

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


import DAO.Student;
import DAO.StudentDAO;

/**
 * Servlet implementation class Studentall
 */
@WebServlet("/Studentall")
public class Studentall extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Studentall() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @throws IOException 
	 * @throws ServletException 
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
		// TODO Auto-generated method stub
		StudentDAO sd = new StudentDAO();
		try {
			List<Student> list = sd.findall();
			request.setAttribute("list", list);
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		request.getRequestDispatcher("showall.jsp").forward(request, response);
		
	}

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

}

Servlets.StudentDelete.java(控制刪除記錄)

package Servlets;

import java.io.IOException;
import java.io.PrintWriter;

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

import DAO.StudentDAO;

/**
 * Servlet implementation class StudentDelete
 */
@WebServlet("/StudentDelete")
public class StudentDelete extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public StudentDelete() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		String id = request.getParameter("t_id");
		try {
			new StudentDAO().remove(id);
			//PrintWriter pw = response.getWriter();
			//pw.print(id);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			
		}
	}

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

}

Servlets.StudentFind.java(控制查找）

package Servlets;

import java.io.IOException;
import java.util.List;

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

import DAO.Student;
import DAO.StudentDAO;

/**
 * Servlet implementation class StudentFind
 */
@WebServlet("/StudentFind")
public class StudentFind extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public StudentFind() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		String name = request.getParameter("t_name");
		StudentDAO std = new StudentDAO();
		try {
			List<Student> list = std.find(name);
			request.setAttribute("list", list);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		request.getRequestDispatcher("showFind.jsp").forward(request, response);
		
	}

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

}

Servlets.Studentupdate.java(控制更新)

package Servlets;

import java.io.IOException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

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

import DAO.Student;
import beans.JDBCUtils;

/**
 * Servlet implementation class Studentupdate
 */
@WebServlet("/Studentupdate")
public class Studentupdate extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Studentupdate() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		String id = request.getParameter("t_id");
		if(id==null||id.equals("")) id = "1";
		Connection con = null;
		try {
			con  = JDBCUtils.getConnection();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		String sql = "select * from user where id = " + id;
		Statement smt = null;
		try {
			 smt = con.createStatement();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		ResultSet rs = null;
		try {
			rs = smt.executeQuery(sql);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		Student stu = new Student();
		try {
			while(rs.next()) {
				stu.setName(rs.getString(2));
				stu.setAge(rs.getInt(3));
				stu.setSex(rs.getString(4));
				stu.setHeight(rs.getFloat(5));
				stu.setWeight(rs.getFloat(6));
			}
			request.setAttribute("stu", stu);
			request.setAttribute("id", id);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		request.getRequestDispatcher("updateEditor.jsp").forward(request, response);
		
	}

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

}

Servlets.Studentupdate2.java(控制更新)

package Servlets;

import java.io.IOException;
import java.io.PrintWriter;

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

import DAO.Student;
import DAO.StudentDAO;

/**
 * Servlet implementation class Studentupdate2
 */
@WebServlet("/Studentupdate2")
public class Studentupdate2 extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Studentupdate2() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		request.setCharacterEncoding("utf-8");
		String name = request.getParameter("t_name");
		String id = request.getParameter("id");
		int  age = Integer.parseInt(request.getParameter("t_age"));
		String sex = request.getParameter("t_sex");
		float height = Float.parseFloat(request.getParameter("t_height"));
		float weight = Float.parseFloat(request.getParameter("t_weight"));
		StudentDAO std = new StudentDAO();
		//PrintWriter pw = response.getWriter();
		//pw.print(id);
		try {
			std.update(new Student(name,age,sex,height,weight),id);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

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

}
發表評論
所有評論
還沒有人評論，想成為第一個評論的人麼? 請在上方評論欄輸入並且點擊發布.
相關文章

ASP.NET AJAX客戶端編程之旅（三）——讓JavaScript和C#無障礙溝通：數據類型自動轉換&序列化（轉載）

ASP.NET AJAX客戶端編程之旅（三）——讓JavaScript和C#無障礙溝通：數據類型自動轉換&序列化 摘要       通過前兩篇文章，我們知道使用了ASP.NET AJAX框架後，在JavaScript中調用後臺WebSe

★海戰鷹 2022-04-02 14:30:32

ASP.NET AJAX客戶端編程之旅（二）——知其所以然（轉載）

ASP.NET AJAX客戶端編程之旅（二）——知其所以然 摘要       在上一篇文章中，做了一個“Hello！ASP.NET AJAX”的小例子，但是並沒有對其中的技術做解釋。這一篇中，將探討一下使用ASP.NET AJAX框架在

★海戰鷹 2022-04-02 14:30:32

ASP.NET AJAX客戶端編程之旅（六）——來做一個自己的客戶端控件（轉載）

ASP.NET AJAX客戶端編程之旅（六）——來做一個自己的客戶端控件 摘要       通過前面的文章，我們瞭解了ASP.NET AJAX框架的很多知識。在這一篇文章中，我們來做一個自己的ASP.NET AJAX客戶端控件：Pass

★海戰鷹 2022-04-02 14:30:32

Vue實現音樂播放效果（適合小白學習）

Vue實現音樂播放效果（適合小白學習）播放器介紹五個html主要標籤功能介紹（1）搜索（2）播放效果：完整代碼： 播放器介紹 總體的效果如圖所示，沒有加很多css特效，需要美化的小白，可以自行添加，本博客只負責介紹原理。 五個ht

至尊小涛丫 2020-07-07 13:56:09

登錄證書驗證

需求:爲了提高安全性.某人擁有某個證書,才能進行登錄.環境:Tomcat設計:採用SSL,https登錄.服務器驗證證書.(貌似SSL裏面自己做了驗證

zengcity 2020-07-07 05:58:52

tomcat 的server.xml

tomcat 的server.xml 中的<Context  docBase="項目工程文件路徑"   path="/aa/bb/cc/dd"   reloadable="true"  source=""/> 訪問URL: http:/

xiaodanjava 2020-07-06 07:09:51

python關於驗證碼

對於爬蟲而言驗證碼是一定要經過的坎，對於網站開發而言，驗證碼有着大量生成方法，網站開發者爲了應對爬蟲以及方便用戶閱讀，都會有自己的一套方法。 這裏介紹了python PIL生成驗證碼的一種通用方法。 import random f

大佬请带带我 2020-07-06 05:23:14

使用Web標準建站第9天：CSS佈局入門(2)

接下來開始要真正設計佈局了。和傳統的方法一樣，你首先要在腦海裏有大致的輪廓構 想，然後用photoshop把它畫出來。你可能看到有關web標準的站點大都很樸素，因爲web標準更關注結構和內容，實際上它與網頁的美觀沒有根本衝 突，你想怎麼設

天边一只鼠 2020-07-06 03:36:07

HTML基礎－HTML文檔基本結構

HTML－＞超文本標記語言、網頁設計的基本語言。HTML的命令也稱爲標記，用於控制HTML文檔的內容和外觀。HTML的標記大多數是成對出現的，開始標記是一對括號<TAG>，表示命令的開始；命令的結束用</TAG>表示；標記不區分大小寫。H

天边一只鼠 2020-07-06 03:36:07

Tomcat6.0.18還不錯

Tomcat 最新的版本 6.0.18 修改了一些 bug 。這次升級 配置上也採用了 Executor 和 NIO 方式。   Tomcat6  maxSpareThreads參數不再被支持   minSpareT

iteye_15098 2020-07-06 02:41:42

AJAX 請求出現編碼問題處理過程

   WEB 應用或多或少總會用到AJAX 請求，而有時AJAX 請求會出現一些問題：比如編碼問題，明明輸入的是中文咋到數據庫就成“???”了呢？ 爲此我總結了一下處理此類事情的方法： 1. 使用encodeURI() 函數將字符串作爲

戴子 2020-07-06 01:12:50

JAVA 後臺計算 經緯度 最短距離

1、 代碼塊 package com.ilogie.tms.util; import java.io.IOException; import java.math.BigDecimal; import java.text.MessageF

戴子 2020-07-06 01:12:50

如何用JAVA獲取GOOGLE 地圖經緯度，地址信息

第一步 、申請一個GOOGLE地圖的KEY 1、根據地址獲取經緯度 public static void getGoogleLatLng() { CloseableHttpClient httpclient = HttpCli

戴子 2020-07-06 01:12:50

tomcat 中文URL路徑無法訪問解決方案

  在tomcat的web工程中加入了中文URL鏈接後，提示頁面不存在。 經過調查發現，原來是 tomcat默認情況下對於GET協議中的URL編碼都是ISO-8859-1,而這個字符集是不支持中文等雙字節的信息的。URL路徑和中文文件等鏈

weivs929 2020-07-05 10:11:44

機器學習線上預測流程和方案

 我們知道模型通過離線方式訓練出來後，怎麼進行預測呢？如何在線上實時打分。 ​ 我們可以將模型結果轉爲一種叫pmml的格式文件，然後交由openscoring的Web 服務組件來進行線上打分預測。openscoring是一套解決方案（官網

a18998154627 2020-07-05 03:54:44