java程序设计课期中考试——数据库的增删改查和简单的js界面

其他 2019-12-10 19:51:01 阅读次数: 0

首先是设计思路，对于数据库的增删改查，我们借助Ecilipse来进行前端和后端的编写。Ecilipse是可以进行java web项目的操作的。

前端，我们选择用使用jsp，所谓的jsp就是可以嵌入其他语言的html,各种标识语言和html语法一致，但为了在本界面检测各种信息的正确性，需要嵌入java的语句进行判断。

对于数据库的增删改查，我们使用sql语句，并且导入了相应的mysql的jar包，方便我们用java对数据库进行操作。

整体来说，我们编写使用了MVC模式(model-view-controler)来实现各种设计。具体的解释不再赘述，下面是一些效果图：

(主界面)

 （添加信息界面，即增删改查中的增）

 （修改界面，即增删改查中的改）

 

 （删除界面，即增删改查中的删）

 （查询界面，即查。该界面设计了一个综合查询功能，即可以进行多条件的综合查询）

下面是各个界面和后端的代码：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>石家庄铁道大学青年志愿者服务网</title>
</head>
<body>
<div align="center" style="color:#6C3365;position:relative;top:85px;font-size:25px">
  <p>青年志愿服务网</p>
</div>
<div align="center" style="position:relative;top:100px">
<button onclick="window.location.href='add.jsp'">志愿者信息登记</button>
</div>
<div align="center" style="position:relative;top:110px">
<button onclick="window.location.href='revise.jsp'">修改志愿者信息</button>
</div>
<div align="center" style="position:relative;top:120px;">
<button onclick="window.location.href='delete.jsp'">删除志愿者信息</button>
</div>
<div align="center" style="position:relative;top:130px">
<button onclick="window.location.href='search.jsp'">查询志愿者信息</button>
</div>
<div align="center" style="position:relative;top:140px">
<button onclick="window.location.href='Servlet?method=show'">志愿者信息浏览</button>
</div>
<div align="center" style="color:#6C3365;position:relative;top:150px">
<p>Designed By wushen</p>
</div>
</body>
</html>
主界面代码 
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>志愿者信息录取界面</title>
<STYLE TYPE="text/css">
<!--
table{margin:auto}
-->
</STYLE>
<script type="text/javascript">
/*表单校验*/
function check() {
    f=0;
    var  name = document.getElementById("name").value;
    if(name.length!=0){
        f++;
    }
    else {alert("请输入姓名!");return false;}
    var sex=document.getElementById("sex").value;
    if(sex.length!=0){
        f++;
    }
    else {alert("请输入性别!");return false;}
    var nation=document.getElementById("nation").value;
    if(nation.length!=0){
        f++;
    }
    else {alert("请输入民族!");return false;}
    var time =document.getElementById("time").value;
    if(time.length!=0){
        f++;
    }
    else {alert("请输入注册时间!");return false;}
    var political =document.getElemById("political").value;
    if(political.length!=0||political.value!="--请选择--"){
        f++;
    }
    else {alert("请选择政治面貌!");return false;}
    if(f>=6){
        alert("添加志愿者信息成功!");
        return true;
    }
    else{
        alert("添加失败,请检查信息是否正确!");
        return false;
    }
}

</script>
</head>
<body>
<h1>添加志愿者信息界面</h1>
<p align="right"><a href="main.jsp">返回主界面</a></p><hr>
<form action="Servlet?method=add" method="post" onsubmit="return check()"><br/><br/><br/><br/><br/><br/><br/>
<table frame= "box">
            <tr>
            <td>姓名</td>
                <td><input type="text"  id="name" name="name" value="" ></td>
            </tr>
            <tr>
            <td>性别</td>
            <td>
               <input type="radio" name="sex" value="男">男
               <input type="radio" name="sex" value="女">女
              </td>
             </tr>
             <tr>
            <td>民族</td>
               <td><input type="text" id="nation" name="nation" value=""></td>
               </tr>
             <tr>
             <td>注册时间</td>
                  <td><input type="text" id="time" name="time" value=""></td>
             </tr>
             <tr>
                <td>年龄</td>
                  <td><input type="text" id="year" name="year" value=""></td>
             </tr>
             <tr>
            <td>政治面貌:</td>
              <td>
               <select id="political" name="political" >
                    <option>--请选择--</option>
                        <option  value="群众">群众</option>
                        <option  value="共青团员">共青团员</option>
                        <option  value="中共党员">中共党员</option>
                    </select>
               </td>
            </tr>
            <tr>
               <td>服务类别(最多四项)</td>
               <td>
               <div>
               <input type="checkbox" name="type" value="扶危济贫">扶危济贫
               <input type="checkbox" name="type" value="敬老助残">敬老助残
               <input type="checkbox" name="type" value="社区服务">社区服务
               <input type="checkbox" name="type" value="秩序维护">秩序维护
               <input type="checkbox" name="type" value="文体服务">文体服务
               </div>
               <div>
               <input type="checkbox" name="type" value="环境保护">环境保护
               <input type="checkbox" name="type" value="治安防范">治安防范
               <input type="checkbox" name="type" value="医疗救治">医疗救治
               <input type="checkbox" name="type" value="法律援助">法律援助
               <input type="checkbox" name="type" value="大型活动">大型活动
               </div>
               <div>
               <input type="checkbox" name="type" value="心理疏导">心理疏导
               <input type="checkbox" name="type" value="精神抚慰">精神抚慰
               <input type="checkbox" name="type" value="支教支医">支教支医
               <input type="checkbox" name="type" value="科学普及">科学普及
               <input type="checkbox" name="type" value="应急救援">应急救援
               </div>
               <div>
               <input type="checkbox" name="type" value="便民服务">便民服务
               <input type="checkbox" name="type" value="民事调解">民事调解
               <input type="checkbox" name="type" value="文明引导">文明引导
               <input type="checkbox" name="type" value="安全生产">安全生产
               <input type="checkbox" name="type" value="禁毒宣传">禁毒宣传
               </div>
               </td>
             </tr>
           <tr>
            <td><td>
                <td> <button type="submit" >提&nbsp;&nbsp;&nbsp;&nbsp;交</button></td>
            </tr>
            <tr>
                <td colspan="2">
                    <font color="red">${message}</font>
                </td>
            </tr>
        </table>
</form>
</body>
</html>
添加信息界面 
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
         <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>志愿者信息修改界面</title>
</head>
<body>
    <h1 align="left">按姓名查询并修改界面</h1><p align="right"><a href="main.jsp">返回主界面</a></p><hr>
    <form action="Servlet?method=ch_u" method="post" >
        <table align="center" bgcolor="#FFFFFF">
            <tr>
                <td>
                    姓名
                </td>
                <td >
                    <input type="text" name="name" id="name">
                </td>
            </tr>
            <tr>
                <td colspan="2">
                    <input class="btn btn-default" type="submit" value="查询">
                </td>
            </tr>
            <tr>
                <td colspan="2">
                    <font color="green">${message}</font>
                </td>
            </tr>
        </table>
    </form>
    <c:if test="${message eq '查询成功'}">    
    <form action="Servlet?method=revise" method="post" onsubmit="return check()"><br/><br/><br/><br/><br/><br/><br/>
<table frame= "box">
            <tr>
            <td>姓名</td>
                <td><input type="text"  id="name" name="name" value="${U.name}" ></td>
            </tr>
            <tr>
            <td>性别</td>
            <td>
               <input type="radio" name="sex" value="男">男
               <input type="radio" name="sex" value="女">女
              </td>
             </tr>
             <tr>
            <td>民族</td>
               <td><input type="text" id="nation" name="nation" value="${U.nation}"></td>
               </tr>
             <tr>
             <td>注册时间</td>
                  <td><input type="text" id="time" name="time" value="${U.time}"></td>
             </tr>
             <tr>
                <td>年龄</td>
                  <td><input type="text" id="year" name="year" value="${U.year}"></td>
             </tr>
             <tr>
            <td>政治面貌:</td>
              <td>
               <select id="political" name="political" >
                    <option value="${U.political}"></option>
                        <option  value="群众">群众</option>
                        <option  value="共青团员">共青团员</option>
                        <option  value="中共党员">中共党员</option>
                    </select>
               </td>
            </tr>
            <tr>
               <td>服务类别(最多四项)</td>
               <td>已选:${U.type}</td><br>
               <td>
               <input type="checkbox" name="type" value="扶危济贫">扶危济贫
               <input type="checkbox" name="type" value="敬老助残">敬老助残
               <input type="checkbox" name="type" value="社区服务">社区服务
               <input type="checkbox" name="type" value="秩序维护">秩序维护
               <input type="checkbox" name="type" value="文体服务">文体服务
               <input type="checkbox" name="type" value="环境保护">环境保护
               <input type="checkbox" name="type" value="治安防范">治安防范
               <input type="checkbox" name="type" value="医疗救治">医疗救治
               <input type="checkbox" name="type" value="法律援助">法律援助
               <input type="checkbox" name="type" value="大型活动">大型活动
               <input type="checkbox" name="type" value="心理疏导">心理疏导
               <input type="checkbox" name="type" value="精神抚慰">精神抚慰
               <input type="checkbox" name="type" value="支教支医">支教支医
               <input type="checkbox" name="type" value="科学普及">科学普及
               <input type="checkbox" name="type" value="应急救援">应急救援
               <input type="checkbox" name="type" value="便民服务">便民服务
               <input type="checkbox" name="type" value="民事调解">民事调解
               <input type="checkbox" name="type" value="文明引导">文明引导
               <input type="checkbox" name="type" value="安全生产">安全生产
               <input type="checkbox" name="type" value="禁毒宣传">禁毒宣传
               </td>
             </tr>
           <tr>
            <td><td>
                <td> <button type="submit" >修&nbsp;&nbsp;&nbsp;&nbsp;改</button></td>
            </tr>
            <tr>
                <td colspan="2">
                    <font color="green">${message}</font>
                </td>
            </tr>
        </table>
</form>
    </c:if>
</body>
</html>
修改信息界面 
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
     <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>志愿者信息删除界面</title>
</head>
<body>
    <h1 align="left">按姓名查询并删除界面</h1><p align="right"><a href="main.jsp">返回主界面</a></p><hr>
    <form action="Servlet?method=d_u" method="post"  >
        <table align="center" bgcolor="#FFFFFF">
            <tr>
                <td>
                    姓名
                </td>
                <td >
                    <input type="text" name="name" id="name">
                </td>
            </tr>
            <tr>
                <td colspan="2">
                    <input class="btn btn-default" type="submit" value="查询">
                </td>
            </tr>
            <tr>
                <td colspan="2">
                    <font color="red">${message}</font>
                </td>
            </tr>
        </table>
    </form>
    <c:if test="${message eq '查询成功'}">    
    <form action="Servlet?method=delete" method="post" onSubmit="return confirm('真的要删除吗?');"><br/><br/><br/><br/><br/><br/><br/>
<table frame= "box">
            <tr>
            <td>姓名</td>
                <td><input type="text"  id="name" name="name" value="${U.name}" ></td>
            </tr>
            <tr>
            <td>性别</td>
            <td> 
               <input type="radio" name="sex" value="男">男
               <input type="radio" name="sex" value="女">女
              </td>
             </tr>
             <tr>
            <td>民族</td>
               <td><input type="text" id="nation" name="nation" value="${U.nation}"></td>
               </tr>
             <tr>
             <td>注册时间</td>
                  <td><input type="text" id="time" name="time" value="${U.time}"></td>
             </tr>
             <tr>
                <td>年龄</td>
                  <td><input type="text" id="year" name="year" value="${U.year}"></td>
             </tr>
             <tr>
            <td>政治面貌:</td>
              <td>
               <select id="political" name="political" >
                    <option value="${U.political}"></option>
                        <option  value="群众">群众</option>
                        <option  value="共青团员">共青团员</option>
                        <option  value="中共党员">中共党员</option>
                    </select>
               </td>
            </tr>
            <tr>
               <td>服务类别(最多四项)</td>
               <td>已选:${U.type}</td><br>
               <td>
               <input type="checkbox" name="type" value="扶危济贫">扶危济贫
               <input type="checkbox" name="type" value="敬老助残">敬老助残
               <input type="checkbox" name="type" value="社区服务">社区服务
               <input type="checkbox" name="type" value="秩序维护">秩序维护
               <input type="checkbox" name="type" value="文体服务">文体服务
               <input type="checkbox" name="type" value="环境保护">环境保护
               <input type="checkbox" name="type" value="治安防范">治安防范
               <input type="checkbox" name="type" value="医疗救治">医疗救治
               <input type="checkbox" name="type" value="法律援助">法律援助
               <input type="checkbox" name="type" value="大型活动">大型活动
               <input type="checkbox" name="type" value="心理疏导">心理疏导
               <input type="checkbox" name="type" value="精神抚慰">精神抚慰
               <input type="checkbox" name="type" value="支教支医">支教支医
               <input type="checkbox" name="type" value="科学普及">科学普及
               <input type="checkbox" name="type" value="应急救援">应急救援
               <input type="checkbox" name="type" value="便民服务">便民服务
               <input type="checkbox" name="type" value="民事调解">民事调解
               <input type="checkbox" name="type" value="文明引导">文明引导
               <input type="checkbox" name="type" value="安全生产">安全生产
               <input type="checkbox" name="type" value="禁毒宣传">禁毒宣传
               </td>
             </tr>
           <tr>
            <td><td>
                <td> <button type="submit" >删&nbsp;&nbsp;&nbsp;&nbsp;除</button></td>
            </tr>
            <tr>
                <td colspan="2">
                    <font color="blue">${message}</font>
                </td>
            </tr>
        </table>
</form>
    </c:if>
</body>
</html>
删除信息界面 
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
       <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>志愿者信息查找界面</title>
</head>
<body>
<h1 align="left">查询界面</h1><p align="right"><a href="main.jsp">返回主界面</a></p><hr>
    <form action="Servlet?method=q_u" method="post" >
        <table align="center" bgcolor="#FFFFFF">
            <tr>
                <td>
                    姓名
                </td>
                <td>
                    <input type="text" name="name" id="name">
                </td>
                <td>
                  <select id="type1" name="type1" >
                    <option>--请选择--</option>
                        <option  value="0">精确查询</option>
                        <option  value="1">模糊查询</option>
                    </select>
                    </td>
            </tr>
                <tr>
                <td >
                    性别
                </td>
                  <td>
                    <input type="text" name="sex" id="sex" >
                    </td> 
                    </tr>
                    <tr>
                    <td>
                    民族
                    </td>
                    <td>
                    <input type="text" name="nation" id="nation">
                    </td>
                    </tr>
                    <tr>
                    <td>政治面貌</td>
                    <td><input type="text" name="political" id="political"> </td>
                    </tr>    
                   <tr>
                     <td>服务类别</td>
                     <td><input type="text" name="type" id="type"></td>
                     </tr>
                     <tr>
                     <td>注册时间</td>
                     <td><input type="text" name="time" id="time"></td>
                     </tr>
            <tr>
                <td colspan="2">
                    <input class="btn btn-default" type="submit" value="查询">
                </td>
            </tr>
            
            <tr>
                <td colspan="2">
                    <font color="red">${message}</font>
                </td>
            </tr>
        </table>
    </form>
    <c:if test="${message eq '查询成功'}">    
       <table align="center" bgcolor="#FFFFFF"  class="table table-bordered" >
            <tr>
                <td>
                    姓名
                </td>
                <td>
                    ${U.name} 
                </td>
            </tr>
            <tr>
                <td>
                    性别
                </td>
                <td>
                    ${U.sex}<br>
                </td>
                </tr>
                <tr>
                <td>
                   民族
                   </td>
                   <td>
                   ${U.nation}
                   </td>
                   <tr>
                   <td>
                   注册时间
                   </td>
                   <td>
                   ${U.time}
                   </td>
                   <tr>
                   <td>
                   年龄
                   </td>
                   <td>
                   ${U.year}
                   </td>
                   </tr>
                   <tr>
                   <td>
                   政治面貌
                   </td>
                   <td>
                   ${U.political}
                   </td>
                   </tr>
                   <tr>
                   <td>
                   服务类别
                   </td>
                   <td>
                   ${U.type}
                   </td>
                   </tr>
        </table>
      </c:if>
</body>
</html>
查询信息界面 
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
       <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
    
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>志愿者信息浏览界面</title>
</head>
<body>
<h2 align=center>所有志愿者信息</h2><p align="right"><a href="main.jsp">返回主界面</a></p><hr>
<form action="Servlet?method=showinfo" method="post">
<table align=center>
<tr>
<th class="w1">姓名</th>
<th class="w1">性别</th>
<th class="w1">民族</th>
<th class="w1">政治面貌</th>
</tr>
       <c:forEach items="${userlist}" var="item">
       <tr>
              <td class="w1"><a href="Servlet?method=showinfo&name=${item.name}">${item.name}</a></td>
              <td class="w1">${item.sex}</td>
              <td class="w1">${item.nation}</td>
              <td class="w1">${item.political}</td>
      </tr>
</c:forEach>
</table>
</form>
</body>
</html>
浏览志愿者信息简洁界面 
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
          <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>志愿者详细信息浏览界面</title>
</head>
<body>
<h2 align=center>志愿者信息</h2><p align="right"><a href="main.jsp">返回主界面</a></p><hr>
<table align=center>
<tr>
<th class="w1">姓名</th>
<th class="w1">性别</th>
<th class="w1">民族</th>
<th class="w1">政治面貌</th>
<th class="w1">注册时间</th>
<th class="w1">年龄</th>
<th class="w1">服务类别</th>
</tr>
       <tr>
              <td class="w1">${U.name}</td>
              <td class="w1">${U.sex}</td>
              <td class="w1">${U.nation}</td>
              <td class="w1">${U.political}</td>
              <td class="w1">${U.time}</td>
              <td class="w1">${U.year}</td>
              <td class="w1">${U.type}</td>
              
      </tr>
</table>
</body>
</html>
详细信息界面

Sevlet层：

package servlet;
import java.io.IOException;
import user.User;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.util.ArrayList;
import java.util.List;

import dao.Dao;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Servlet extends HttpServlet{
    private static final long serialVersionUID = 1L;
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Servlet() {
        super();
    }
    Dao dao = new Dao();
    private void add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        User user = new User(req.getParameter("name"),req.getParameter("sex"),req.getParameter("nation"),req.getParameter("time"),req.getParameter("year"),req.getParameter("political"),req.getParameter("type"));
          
          if(dao.add(user.getname(),user.getsex(),user.getnation(),user.gettime(),user.getyear(),user.getpolitical(),user.gettype() )) {
              req.setAttribute("message", "添加志愿者信息成功");
              req.getRequestDispatcher("show.jsp").forward(req,resp);    
          }else {
              req.setAttribute("message", "添加志愿者信息失败");
              req.getRequestDispatcher("add.jsp").forward(req,resp);
          }
      }
      private void show(HttpServletRequest req,HttpServletResponse resp)throws ServletException,IOException{
          req.setCharacterEncoding("utf-8");
          List<User>userlist = dao.show();
          req.setAttribute("userlist", userlist);
          req.getRequestDispatcher("show.jsp").forward(req,resp);
      }
      private void showinfo(HttpServletRequest req,HttpServletResponse resp)throws ServletException,IOException{
          req.setCharacterEncoding("utf-8");
          User user = dao.Q_U(req.getParameter("name"),req.getParameter("sex"),req.getParameter("nation"),req.getParameter("time"),req.getParameter("political"),req.getParameter("type"));
          System.out.println(req.getParameter("name"));
          req.setAttribute("U",user);
          req.getRequestDispatcher("showinfo.jsp").forward(req,resp);
      }
      public void delete(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException{
          req.setCharacterEncoding("UTF-8");
          String name=req.getParameter("name");
          if(dao.delete(name)) {//进行数据库的删除操作
              req.setAttribute("message", "删除成功");
          }else {
              req.setAttribute("message", "删除失败");
          }
          req.getRequestDispatcher("delete.jsp").forward(req, resp);
      }
      public void d_u(HttpServletRequest req, HttpServletResponse resp)throws IOException, ServletException {
          User user =dao.Q_U(req.getParameter("name"),req.getParameter("sex"),req.getParameter("nation"),req.getParameter("time"),req.getParameter("political"),req.getParameter("type"));
          if(user!=null) {
              req.setAttribute("message", "查询成功");
              req.setAttribute("U", user);
              req.getRequestDispatcher("delete.jsp").forward(req,resp);    
          }else {
              req.setAttribute("message", "该志愿者信息不存在");
              req.setAttribute("U", user);
              req.getRequestDispatcher("delete.jsp").forward(req,resp);
          }
      }
      public void ch_u(HttpServletRequest req, HttpServletResponse resp)throws IOException, ServletException {
          User user =dao.Q_U(req.getParameter("name"),req.getParameter("sex"),req.getParameter("nation"),req.getParameter("time"),req.getParameter("political"),req.getParameter("type"));
          if(user!=null) {
              req.setAttribute("message", "查询成功");
              req.setAttribute("U", user);
              req.getRequestDispatcher("revise.jsp").forward(req,resp);
          }else {
              req.setAttribute("message", "该志愿者信息不存在");
              req.setAttribute("U", user);
              req.getRequestDispatcher("revise.jsp").forward(req,resp);
          }
      }
      public void revise(HttpServletRequest req,HttpServletResponse resp)throws IOException,ServletException{
          req.setCharacterEncoding("utf-8");
          String name = req.getParameter("name");
          String sex = req.getParameter("sex");
          String nation=req.getParameter("nation");
          String time=req.getParameter("time");
          String year=req.getParameter("year");
          String political = req.getParameter("political");
          String type =req.getParameter("type");
          User user=new User(name,sex,nation,time,year,political,type);    
          dao.revise(user.getname(),user.getsex(),user.getnation(),user.gettime(),user.getyear(),user.getpolitical(),user.gettype());//进行数据库的修改操作
          req.setAttribute("message", "修改成功");
          req.getRequestDispatcher("revise.jsp").forward(req,resp);
      }
      public void q_u(HttpServletRequest req, HttpServletResponse resp)throws IOException, ServletException {
          String type=req.getParameter("type1");
          if(type.equals("0")) {
          User user =dao.Q_U(req.getParameter("name"),req.getParameter("sex"),req.getParameter("nation"),req.getParameter("time"),req.getParameter("political"),req.getParameter("type"));
          if(user!=null) {
              req.setAttribute("message", "查询成功");
              req.setAttribute("U", user);
              req.getRequestDispatcher("search.jsp").forward(req,resp);    
          }else {
              req.setAttribute("message", "该志愿者信息不存在");
              req.setAttribute("U", user);
              req.getRequestDispatcher("search.jsp").forward(req,resp);
          }
          }
          else if(type.equals("1")) {
              
          }
          if(type!="1"&&type!="0"){
              req.setAttribute("message","请选择查询方式");
              req.getRequestDispatcher("search.jsp").forward(req,resp);
          }
      }
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      request.setCharacterEncoding("utf-8");
      String method = request.getParameter("method");
      System.out.println(method);
      if("add".equals(method)) {
          add(request,response);
      }
      else if("show".equals(method)) {
          show(request,response);
      }
      else if("delete".equals(method)) {
          delete(request,response);
      }
      else if("d_u".equals(method)) {
          d_u(request,response);
      }
      else if("revise".equals(method)) {
          revise(request,response);
      }
      else if("q_u".equals(method)) {
          q_u(request,response);
      }
      else if("ch_u".equals(method)) {
          ch_u(request,response);
      }
      else if("showinfo".equals(method)) {
          showinfo(request,response);
      }
      }
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
          doGet(request, response);
      }
}
Servlet

封装用户属性的java bean

package user;

public class User {
    private String name;
    private String sex;
    private String nation;
    private String time;
    private String year;
    private String political;
    private String type;
    public User(String name,String sex,String nation,String time,String year,String political,String type){
        this.name=name;
        this.sex=sex;
        this.nation=nation;
        this.time=time;
        this.year=year;
        this.political=political;
        this.type=type;
    }
    public String getname() {
        return name;
    }
    public String getsex() {
        return sex;
    }
    public String getnation() {
        return nation;
    }
    public String gettime() {
        return time;
    }
    public String getyear() {
        return year;
    }
    public String getpolitical() {
        return political;
    }
    public String gettype() {
        return type;
    }
}
User

Dao层

package dao;

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

import database.DB;
import user.User;

public class Dao {
     public static boolean add(String name,String sex,String nation,String time,String year,String political,String type) {
            Connection conn = null;
            PreparedStatement pstmt = null;
            boolean pd = false;
            System.out.println("add run!");
            try {
                //获取连接
                conn = DB.getConn();
                //编写语句
                String sql = "insert into volunteer values(?,?,?,?,?,?,?)";
                //预编译
                pstmt = conn.prepareStatement(sql);
                //设置数据
                pstmt.setString(1, name);
                pstmt.setString(2, sex);
                pstmt.setString(3, nation);
                pstmt.setString(4,time);
                pstmt.setString(5,year);
                pstmt.setString(6,political);
                pstmt.setString(7,type); 
                //执行
                int res = pstmt.executeUpdate();
                //判断
                if(res>0) {
                    pd=true;
                }else {
                    pd=false;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }finally {
                
                DB.close(pstmt,conn);
            }
            return pd;
        }
       public boolean delete(String name) {
           boolean pd=false;
            Connection connection = DB.getConn();
            String sql = "delete from volunteer where name = ?";
            PreparedStatement preparedStatement = null;
            System.out.println("detelte run!");
            try {
                preparedStatement = connection.prepareStatement(sql);
                preparedStatement.setString(1, name);
                int res=preparedStatement.executeUpdate();
                if(res>0) {
                    pd=true;
                }
                else {
                    pd=false;
                }
            } catch (Exception e) {
            
                e.printStackTrace();
            }finally {
                DB.close(preparedStatement,connection);
            }
            return pd;
        }
       public void revise(String name,String sex,String nation,String time,String year,String political,String type) {
            
            Connection connection = DB.getConn();
            //准备sql语句
            String sql = "update volunteer set name = ? , sex=?,nation = ?,time=?,year=?,political=?,type=?";
            //创建语句传输对象
            PreparedStatement preparedStatement = null;
            try {
                preparedStatement = connection.prepareStatement(sql);
                preparedStatement.setString(1, name);
                preparedStatement.setString(2, sex);
                preparedStatement.setString(3, nation);
                preparedStatement.setString(4,time);
                preparedStatement.setString(5,year);
                preparedStatement.setString(6,political);
                preparedStatement.setString(7,type);
                preparedStatement.executeUpdate();
            } catch (Exception e) {
                
                e.printStackTrace();
            }finally {
                DB.close(preparedStatement,connection);
            }
            
        }
       public List<User> show() {
           List<User> userlist =new ArrayList<>();
           Connection conn = DB.getConn();
           ResultSet rs= null;
           String sql="select * from volunteer";
           User user =null;
           Statement stmt=null;
           try {
               stmt=conn.createStatement();
               rs=stmt.executeQuery(sql);
               while(rs.next()){
                   String name=rs.getString("name");
                   String sex=rs.getString("sex");
                   String nation=rs.getString("nation");
                   String time=rs.getString("time");
                   String year=rs.getString("year");
                   String political =rs.getString("political");
                   String type=rs.getString("type");
                   user = new User(name,sex,nation,time,year,political,type);
                   userlist.add(user);
               }
           }catch(Exception e) {
               e.printStackTrace();
           }
           finally {
               DB.close(rs,stmt,conn);
           }
           return userlist;
       }
       public User Q_U(String name,String sex1,String nation1,String time1,String political1,String type1){
           String sql="select * from volunteer where 1 = 1";
           Connection conn=null;
           PreparedStatement pstmt = null;
           ResultSet rs= null;
           if(name!=null) {
               sql+="and name= ? ";
           }
           if(sex1!=null) {
               sql+="and sex= ? ";
           }
           System.out.println(sql);
           try {           
               conn=DB.getConn();
               pstmt=(PreparedStatement) conn.prepareStatement(sql);
               pstmt.setString(1,name);
               pstmt.setString(2,sex1);
               rs =(ResultSet)pstmt.executeQuery();
               while(rs.next()) {
                   String name1=rs.getString("name");
                   String sex=rs.getString("sex");
                   String nation=rs.getString("nation");
                   String time =rs.getString("time");
                   String year=rs.getString("year");
                   String political =rs.getString("political");
                   String type=rs.getString("type");
                   User user = new User(name1,sex,nation,time,year,political,type);
                   return user;
               }
           }catch(Exception e) {
               e.printStackTrace();
           }finally {
               DB.close(rs,pstmt,conn);
           }
           return null;
       }
       
}

连接数据库的java bean

package database;

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

public class DB {
    public static String db_url = "jdbc:mysql://localhost:3306/student?useSSL=false&serverTimezone=UTC&characterEncoding=UTF-8&useOldAliasMetadataBehavior=true";
    public static String db_user = "root";
    public static String db_pass = "abc456";

    public static Connection getConn () {
        Connection conn = null;
        
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");//加载驱动
            conn = DriverManager.getConnection(db_url, db_user, db_pass);
        } catch (Exception e) {
            e.printStackTrace();
        }
        
        return conn;
    }

    /**
     * 关闭连接
     * @param state
     * @param conn
     */
    public static void close (Statement state, Connection conn) {
        if (state != null) {
            try {
                state.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    public static void close (ResultSet rs, Statement state, Connection conn) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        if (state != null) {
            try {
                state.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) throws SQLException {
        Connection conn = getConn();
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        String sql ="select * from USER";
        pstmt = conn.prepareStatement(sql);
        rs = pstmt.executeQuery();
        if(rs.next()){
            System.out.println("空");
        }else{
            System.out.println("不空");
        }
    }
}
Database

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