笔记 Java web实现用户登录、数据库数据查询、数据删除等功能

来源：互联网发布：wsn网络分析器sniffer 编辑：程序博客网时间：2024/06/05 06:59

被要求做服务器端给自己增加工作量纵然是不愉快的，毕竟自以为APP已经完成就可以结题，指导老师教育一波实现界面友好、系统完整，感悟颇深，于是充满兴趣与干劲的开始撸服务器端，可是原来这方面的知识储备只有Ｈ５这部分的静态页面知识，做个页面so easy ，问题是要进行数据库，客户端，前端、后台之间的交互，这方面一窍不通，忙活好久，写这篇Blog记录下2017.4的服务器端，相信以后必定会超过现在。

这是一个Android APP->server的系统

从安卓客户端获取上传数据到servlet，然后存到数据库Mysql

用户登录

查看数据

对数据进行处理等

要有mysql-connector-java-5.6-bin

在这之前先联系数据库MYSQL

DBConnection

import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.Statement;import java.util.ArrayList;import com.mysql.jdbc.ResultSet;import com.pro.Information.Information;public class DBConnection {static{try{Class.forName("com.mysql.jdbc.Driver");}catch(ClassNotFoundException e){System.out.println("加载驱动错误");e.printStackTrace();}}public static Connection getConnection(){ Connection conn=null;try{conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/Creation", "root", "");System.out.println("取得连接成功");}catch(Exception e){System.out.println("取得连接错误");e.printStackTrace();} return conn;}public static void close(Statement st,ResultSet rs,Connection conn){try{if(st!=null){st.close();}if(rs!=null){rs.close();}if(conn!=null){conn.close();}}catch(Exception e){e.printStackTrace();}}public static void close(PreparedStatement pst,Connection conn){try{if(pst!=null){pst.close();}if(conn!=null){conn.close();}}catch(Exception e){e.printStackTrace();}}}

然后测试一下

DBTest

import java.sql.Connection;import java.sql.ResultSet;import com.mysql.jdbc.Statement;import com.pro.DBConnection.DBConnection;public class DBtest {public static void main(String[] args){Connection conn=DBConnection.getConnection();//if(conn!=null){//System.out.println("OK ");//}else{//System.out.println("fail");//}try{String sql="select*from data";Statement stmt=(Statement)conn.createStatement();ResultSet rs=stmt.executeQuery(sql);while(rs.next()){int id=rs.getInt("id");System.out.println(id);}}catch(Exception e){e.printStackTrace();}}}

有一个information没怎么用

public class Information {private int id;public int getId(){return id;}public void setId(int id){this.id=id;}}

太多了就留了一个发上来

<%@ page language="java" contentType="text/html; charset=utf-8"    pageEncoding="UTF-8"%><!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=ISO-8859-1"><title>登陆</title><style type="text/css"></style></head><body style="background:url(loginback.jpg) no-repeat;position:absolut;"><form method="POST" name="divlogin" action="LoginSelvet">  <div align="center"><p> </p><p> </p><p> </p><p> </p><div  style=" background:url(back.jpg) no-repeat;width:600px;height:300px;"><p> </p><font size=6 color="#2a5caa" face="宋体" ><b><i>欢迎使用查询呼叫评价系统</i></b></font><p> </p><p>账号：    <input type="text" name="username"><br><br>  密码：   <input type="password" name="password"><br><br>  <input type="submit" name="login" value="登陆" onclick="return emptyLogin()">      <input type="reset" name="reset" value="重置"></p><p> </p></div></div><script type="text/javascript">function emptyLogin(){var eusername=document.divlogin.username.value;var epassword=document.divlogin.password.value;if(eusername==""){alert("请输入账号");return false;}if(epassword==""){alert("请输入密码");return false;}}</script></form></body></html>

protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 防乱码response.setContentType("text/html;charset=utf-8");//特别注意，text,写成test，会无脑下载Loginservletresponse.setCharacterEncoding("utf-8");// 获取jsp中填入数据String username = request.getParameter("username");String password = request.getParameter("password");System.out.println(username);System.out.println(password);// 数据库相关String Dusername = null;String Dpassword = null;String sql = null;// 与数据库建立连接try {Class.forName("com.mysql.jdbc.Driver");System.out.println("Loading Database success");} catch (Exception e) {System.out.println("Class not found exception");}String url = "jdbc:mysql://localhost:3306/Creation";Connection con = null;Statement stmt = null;ResultSet rs = null;if (username.equals("admin")&& password.equals("admin")) {//超管，如果超管登录，就跳转到添加管理员界面System.out.println("super manager登陆成功");// 要成功，跳转success.jspresponse.sendRedirect("addmanager.jsp");return;}else{try {con = (Connection) DriverManager.getConnection(url, "root", "");stmt = (Statement) con.createStatement();sql = "select*from manager where username='"+username+"'";rs = stmt.executeQuery(sql);while (rs.next()) {Dusername = rs.getString("username");Dpassword = rs.getString("password");System.out.println(username);System.out.println(password);if (Dusername.equals(username) && Dpassword.equals(password)) {System.out.println("管理员登陆成功");// 要成功，跳转success.jspresponse.sendRedirect("success.jsp");return;}else {System.out.println("登陆失败");response.sendRedirect("fail.jsp");return;}}} catch (Exception e) {e.printStackTrace();}}}

登录使用manager表

先，如果是超级管理员，实现为系统添加管理员功能

addmanager.jsp

很简单的只有账号密码确定按钮

<form method="POST" action="addServlet" name="add"><br><br><br><br><div align="center"><p>添加管理员</p>Musername:<input type="text" name="addun"><br><br>Mpassword:<input type="text" name="addpsw"><br><br><input type="submit" name="submit" value="提交" onclick="addsubmit()"></div></form>

传入addServlet

response.setContentType("text/html;charset=utf-8");response.setCharacterEncoding("utf-8");String Mname=request.getParameter("addun");System.out.println(Mname);Connection conn=DBConnection.getConnection();String sql="insert into manager(username,password) values(?,?)";try{PreparedStatement pst=(PreparedStatement)conn.prepareStatement(sql);pst.setString(1, request.getParameter("addun"));pst.setString(2, request.getParameter("addpsw"));    int result = 0;    result=pst.executeUpdate();    System.out.println("插入成功");}catch(Exception e){e.printStackTrace();}return ;}

我用system.out.print打印当前数据来确认这里确实传入数据，那些bug出的一个个泪流满面啊让人，这么个简单的东西

然后，登录成功了，就显示到数据页面

show.jsp

<body style="background:url(manager.jpg)">      <br>      <br>      <br>      <font size=7 color=#494e8f face="宋体"><center>查询呼叫评价系统管理平台</center></font>      <br>      <br>      <table align="center" bordercolor="#2a5caa">            <tr>                  <td>ID</td>                  <td>乘车舒适度</td>                  <td>有无异味</td>                  <td>安全防范措施</td>                  <td>车辆信息</td>                  <td>核载人数</td>                  <td>服务态度</td>                  <td>道路熟悉度</td>                  <td>驾驶精力</td>                  <td>接听电话</td>                  <td>是否绕路</td>                  <td>您的建议</td>                  <td>管理 </td>            </tr>                  <%             ArrayList<Information> list=(ArrayList<Information>)request.getAttribute("list");            if(list==null||list.size()<1){                  out.print("没有数据");            }else{                  for(Information info:list){            %>                        <tr >                        <td><%=info.getId()%></td>                        <td><%=info.getcarone_feel() %></td>                        <td><%=info.getcartwo_feel() %></td>                        <td><%=info.getcarthree_feel() %></td>                        <td><%=info.getcarfour_feel() %></td>                        <td><%=info.getcarfive_feel() %></td>                        <td><%=info.getdrione_feel() %></td>                        <td><%=info.getdritwo_feel() %></td>                        <td><%=info.getdrithree_feel() %></td>                        <td><%=info.getdrifour_feel() %></td>                        <td><%=info.getdrifive_feel() %></td>                        <td><%=info.getsuggestion() %></td>                        <td>                        <a href="DeleteServlet?id=<%=info.getId()%>">删除</a>                        <a href="DetailServlet?id=<%=info.getId()%>">查看</a>                        <a href="repeat.jsp">回复</a>                        </td>                        </tr>                        <%                  }            }        %></table>            <br> <br> <br>      <div align="center" style="font-size:20; background:#b2d235; width:180px ;height:28px ;position:relative;left:600px;top:10px">                  <%             out.print("数据查询成功");        %>      </div></body>

从findservlet获取

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubConnection conn=DBConnection.getConnection();try{Statement stmt=conn.createStatement();String sql="select*from data";ResultSet rs=stmt.executeQuery(sql);ArrayList<Information> list=new ArrayList<Information>();while(rs.next()){Information info=new Information();info.setId(rs.getInt("id"));info.setcarone_feel(rs.getString("carone_feel"));info.setcartwo_feel(rs.getString("cartwo_feel"));info.setcarthree_feel(rs.getString("carthree_feel"));info.setcarfour_feel(rs.getString("carfour_feel"));info.setcarfive_feel(rs.getString("carfive_feel"));info.setdrione_feel(rs.getString("drione_feel"));info.setdritwo_feel(rs.getString("dritwo_feel"));info.setdrithree_feel(rs.getString("drithree_feel"));info.setdrifour_feel(rs.getString("drifour_feel"));info.setdrifive_feel(rs.getString("drifive_feel"));info.setsuggestion(rs.getString("suggestion"));list.add(info);}request.setAttribute("list", list);rs.close();stmt.close();conn.close();}catch(SQLException e){e.printStackTrace();}request.getRequestDispatcher("show.jsp").forward(request,response);}

这里已经调用了DBConnection数据库连接，放在最后吧，

这是查询到的数据，然后删除功能

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubint id=Integer.valueOf(request.getParameter("id"));try{Connection conn=DBConnection.getConnection();String sql="delete from data where id=?";PreparedStatement ps=conn.prepareStatement(sql);ps.setInt(1, id);ps.executeUpdate();ps.close();conn.close();}catch(Exception e){e.printStackTrace();}response.sendRedirect("FindServlet");//request.getRequestDispatcher("show.jsp").forward(request,response);}

这里的id是从show,jsp点击超链获取的id

再后查看，其实这没什么好看的，，，

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubint id=Integer.valueOf(request.getParameter("id"));System.out.print(id);Connection conn=DBConnection.getConnection();try{Statement stmt=conn.createStatement();String sql="select*from data where id="+id;System.out.println(sql);ResultSet rs=stmt.executeQuery(sql);while(rs.next()){int i=rs.getInt("id");String b=rs.getString("carone_feel");String c=rs.getString("cartwo_feel");String d=rs.getString("carthree_feel");String e=rs.getString("carfour_feel");String f=rs.getString("carfive_feel");String g=rs.getString("drione_feel");String h=rs.getString("dritwo_feel");String j=rs.getString("drithree_feel");String k=rs.getString("drifour_feel");String l=rs.getString("drifive_feel");String m=rs.getString("suggestion");String total=" "+b+" "+c+" "+d+" "+e+" "+f+" "+g+" "+h+" "+j+" "+k+" "+l+" ";request.setAttribute("sug", m);request.setAttribute("id", i);request.setAttribute("message", total);}rs.close();stmt.close();conn.close();}catch(Exception e){e.printStackTrace();}request.getRequestDispatcher("datail.jsp").forward(request, response);}

查看页面就几行字，

回复还在思考，从server传输数据到android

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