javaee CURD U更新操作

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editStudent.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ page import="com.yyy.po.Student" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<% Student student=(Student)request.getAttribute("student"); %>
<form action="UpdateStudentServlet" method="post">
<pre>
  <input type='hidden' name='sid' value="<%=student.getSid() %>"/>
    姓名:<input type='text' name='sname' value="<%=student.getSname() %>" />
   性别:<input type='text' name='sex' value="<%=student.getSex() %>" />
   身份证:<input type='text' name='card_id' value="<%=student.getCard_id() %>" />
  年龄:<input type='text' name='age' value="<%=student.getAge() %>" />
 班主任:<input type='text' name='tid' value="<%=student.getTid() %>" />
   <input type='submit' name='sub' value='修改' />
 </pre>
</form>
</body>
</html>

EditStudentServlet

package com.yyy.servlet;

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

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 com.yyy.po.Student;
import com.yyy.util.DbHelper;

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

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
		//获得sid
				int sid=Integer.parseInt(request.getParameter("sid"));
				//查询当前学生的信息
				String sql="select * from student where sid=?";
				
				List<Object> paramList=new ArrayList<Object>();
				paramList.add(sid);
				
				DbHelper dbHelper=new DbHelper();
				
				List<Map<String, Object>> list=  dbHelper.executeQuery(sql, paramList);
				//传到jsp页面
				
				if(list!=null && list.size()>0)
				{
    
    
					 Student student=new Student();
					 student.setSid(sid);
					 student.setSname(list.get(0).get("sname").toString());
					 student.setSex(list.get(0).get("sex").toString());
					 student.setCard_id(list.get(0).get("card_id").toString());
					 student.setAge(Integer.parseInt(list.get(0).get("age").toString()));
					 student.setTid(Integer.parseInt(list.get(0).get("tid").toString()));
					 
					 request.setAttribute("student",student);
					 
					 request.getRequestDispatcher("editStudent.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);
	}

}

UpdateStudentServlet

package com.yyy.servlet;

import java.io.IOException;
import java.util.ArrayList;
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 com.yyy.util.DbHelper;

/**
 * Servlet implementation class UpdateStudentServlet
 */
@WebServlet("/UpdateStudentServlet")
public class UpdateStudentServlet extends HttpServlet {
    
    
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public UpdateStudentServlet() {
    
    
        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");
		response.setContentType("text/html;charset=utf-8");	
		
		//1.获得表单的数据
		int sid=Integer.parseInt(request.getParameter("sid"));
		String sname=request.getParameter("sname");
		String sex=request.getParameter("sex");
		String card_id=request.getParameter("card_id");
		String age=request.getParameter("age");
		String tid=request.getParameter("tid");
		//2.更新数据库信息
		String sql="update student set sname=?,sex=?,card_id=?,age=?,tid=? where sid=?";
		
		List<Object> paramList=new ArrayList<Object>();
		paramList.add(sname);
		paramList.add(sex);
		paramList.add(card_id);
		paramList.add(age);
		paramList.add(tid);
		paramList.add(sid);
		
		DbHelper dbHelper=new DbHelper();
		
		if(dbHelper.executeUpdate(sql, paramList)>0)
		{
    
    		
		    //3.跳转到显示学生列表页面
			response.sendRedirect("ShowStudentsServlet");
		}
		else
			response.getWriter().println("修改失败");
	}

	/**
	 * @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);
	}

}

javaee CURD U更新操作

editStudent.jsp

EditStudentServlet

UpdateStudentServlet

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