项目的增删改查demo

1.jsp

<?xml version="1.0" encoding="UTF-8" ?>
<%@page import="com.model.td_test"%>
<%@page import="org.apache.jasper.tagplugins.jstl.core.ForEach"%>
<%@page import="java.util.ArrayList"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@page import="java.util.*" %> 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Insert title here</title>
</head>
<body>
<form id ="1" method ="post" action ="/IDUSDemo/InsertDemo">
姓名： <input type ="text" name ="name_one" />
<input type ="submit" value ="插入"/>
</form>
<form id ="2" method ="post" action ="/IDUSDemo/DeleteDemo">
id： <input type ="text" name ="id_one" />
    <input type ="submit" value ="删除"/>
</form>
<form id ="3" method ="post" action ="/IDUSDemo/UpdateDemo">
id： <input type ="text" name ="id_two" />
姓名： <input type ="text" name ="name_two" />
    <input type ="submit" value ="修改"/>
</form>
<form id ="4" method ="post" action ="/IDUSDemo/SelectDemo">
    <input type ="submit" value ="查询"/>
</form>
<h1>${message}</h1>

 <% ArrayList<td_test> list = (ArrayList)request.getAttribute("list2");
     if(list == null){%>
    	<p></p> 
    <% }else{
    	 for(int i = 0;i<list.size();i++){ %> 
     	<p><%=list.get(i).getName()%></p>
     <%}
     }%>
 
    

 

</body>
</html>

2.后端

delete：

package com.util;

import java.io.IOException;

import javax.servlet.RequestDispatcher;
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.mysql.mysqlUtil;

import sun.misc.Perf.GetPerfAction;

/**
 * Servlet implementation class DeleteDemo
 */
@WebServlet("/DeleteDemo")
public class DeleteDemo extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public DeleteDemo() {
        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
		//response.getWriter().append("Served at: ").append(request.getContextPath());
	}

	/**
	 * @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);
		String id =request.getParameter("id_one");
		String sql ="delete from td_test where id="+id;
		int r = mysqlUtil.del(sql);
		if (r==1) {
			request.setAttribute("message","成功删除");
			request.getAttribute("message");
			 RequestDispatcher dispatcher = request.getRequestDispatcher("/html/index.jsp");
			 dispatcher.forward(request, response); 
		}else {
			request.setAttribute("message","失败删除");
			request.getAttribute("message");
			 RequestDispatcher dispatcher = request.getRequestDispatcher("/html/index.jsp");
			 dispatcher.forward(request, response); 
		}
	}

}

insert

package com.util;

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

import javax.servlet.RequestDispatcher;
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.mysql.mysqlUtil;

/**
 * Servlet implementation class InsertDemo
 */
@WebServlet("/InsertDemo")
public class InsertDemo extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public InsertDemo() {
        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
		//response.getWriter().append("Served at: ").append(request.getContextPath());
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		String name =request.getParameter("name_one");
		String sql ="insert into td_test(name)values("+name+")";
		int r =mysqlUtil.add(sql);
		if (r==1) {
			request.setAttribute("message","成功插入");
			request.getAttribute("message");
			 RequestDispatcher dispatcher = request.getRequestDispatcher("/html/index.jsp");
			 dispatcher.forward(request, response); 
		}else {
			
			request.setAttribute("message","失败插入");
			request.getAttribute("message");
			 RequestDispatcher dispatcher = request.getRequestDispatcher("/html/index.jsp");
			 dispatcher.forward(request, response); 
		}
		//doGet(request, response);
	}

}

select

package com.util;

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

import javax.servlet.RequestDispatcher;
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.model.td_test;
import com.mysql.mysqlUtil;

import jdk.nashorn.internal.runtime.linker.LinkerCallSite;

/**
 * Servlet implementation class SelectDemo
 */
@WebServlet("/SelectDemo")
public class SelectDemo extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public SelectDemo() {
        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
		//response.getWriter().append("Served at: ").append(request.getContextPath());
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
//		String id =request.getParameter("id_three");
		String sql ="select name from td_test";
		List<Map<String, String>> list =new ArrayList<>();	
		String[] params = {"name"};
		list =mysqlUtil.show(sql, params);
		
		List<td_test> list2 =new ArrayList<>();
		 
		for (int i = 0; i < list.size(); i++) {
			td_test a =new td_test();
			a.setName(list.get(i).get("name"));
		    list2.add(a);			
		}
		request.setAttribute("list2",list2);
		//ArrayList<td_test> list3 =(ArrayList)request.getAttribute("list2");
		 request.getAttribute("list2");
		// System.out.println(list3.get(0).getName());
		// System.out.println();
		 RequestDispatcher dispatcher = request.getRequestDispatcher("/html/index.jsp");
		 dispatcher.forward(request, response); 
		//doGet(request, response);
	}

}

update：

package com.util;

import java.io.IOException;

import javax.servlet.RequestDispatcher;
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.mysql.mysqlUtil;

/**
 * Servlet implementation class UpdateDemo
 */
@WebServlet("/UpdateDemo")
public class UpdateDemo extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public UpdateDemo() {
        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
		//response.getWriter().append("Served at: ").append(request.getContextPath());
	}

	/**
	 * @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);
		String id =request.getParameter("id_two");
		String name =request.getParameter("name_two");
		String sql ="update td_test set name ="+name+" where id ="+id;
		int r =mysqlUtil.update(sql);
		if (r==1) {
			request.setAttribute("message","成功修改");
			request.getAttribute("message");
			 RequestDispatcher dispatcher = request.getRequestDispatcher("/html/index.jsp");
			 dispatcher.forward(request, response); 
		}else {
			request.setAttribute("message","失败修改");
			request.getAttribute("message");
			 RequestDispatcher dispatcher = request.getRequestDispatcher("/html/index.jsp");
			 dispatcher.forward(request, response); 
		}
	}

}

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项目的增删改查demo

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