最近在做项目web后台数据增删查改的时候，看到一篇较为详细的经典文章，
所以转载了下来，
文章出处在：https://blog.csdn.net/qq_32539825/article/details/70657340
如果作者认为侵权的告诉我，我立马删。
首先jsp 和Servlet语句基本一样，这里的实现需要用到上篇http://blog.csdn.net/qq_32539825/article/details/70494788里的部分内容
包括UserCoon.java UserDao.java User.java
在这里使用jsp语句也实现了分页内容。
1 login.jsp
<html><head><base href="<%=basePath%>"><title>My JSP 'login.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><form action="servlet/Login" method="post">
用户名：<input type="text" name="username" value=""><br>
密 码：<input type="password" name="password" value=""><br>
用户类型：
<select name="type">
<option value="管理员">管理员</option>
<option value="普通用户">普通用户</option>
</select><br>
<input type="submit" value="提交">
<input type="reset" value="取消">
</form> </body>
</html>- dologin.jsp
首先用javabean得到login中的内容，并调用Insert.java插入到数据库
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%@ page import="java.sql.*"%>
<%@ page import="nuc.test.user.User" %>
<%@page import="nuc.test.Dao.UserDao" %><%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><base href="<%=basePath%>"><title>My JSP 'dologin.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><%request.setCharacterEncoding("utf-8"); %>
<jsp:useBean id="user" class="nuc.test.user.User">
<jsp:setProperty name="user" property="*"/>
</jsp:useBean>
<%UserDao usera=new UserDao();usera.Insert(user);%><body>
</html>3 queryBena.java
查询数据库中的内容
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page import="java.sql.*"%>
<%@ page import="nuc.test.user.User" %>
<%@page import="nuc.test.Dao.UserDao" %><%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><base href="<%=basePath%>"><title>My JSP 'queryBean.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><%UserDao user=new UserDao();User usera=new User();ResultSet rst=user.Query();%><table border=1><tr><td>用户名</td><td>密码</td><td>用户类型</td><td colspan="2" align="center">数据操作</td></tr><%while(rst.next()) {%><tr><td><%=rst.getString("username") %></td><td><%=rst.getString("password") %></td><td><%=rst.getString("type") %></td><td><a href="deleteBean.jsp?id=<%=rst.getString("id")%>">删除操作</a></td><td><a href="updateBean.jsp?id=<%=rst.getString("id")%>">更新操作</a></td></tr><%} %></table></body>
</html>4 deleteBean.jsp
点击查询页面上的删除键 便会超链接到deleteBean.jsp并带着值
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%@ page import="java.sql.*"%>
<%@ page import="nuc.test.user.User" %>
<%@page import="nuc.test.Dao.UserDao" %><%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><base href="<%=basePath%>"><title>My JSP 'deleteBean.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><% UserDao user=new UserDao();User usera=new User();usera.setId(request.getParameter("id"));int rest=user.Delete(usera);%></body>
</html>5 updateBean.jsp
首先将需要更新的一条内容输出到网页上，修改后 点提交 调用doUpdateBean.jsp更新
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><%@ page import="java.sql.*"%>
<%@ page import="nuc.test.user.User" %>
<%@page import="nuc.test.Dao.UserDao" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><base href="<%=basePath%>"><title>My JSP 'updateBean.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><%request.setCharacterEncoding("utf-8");UserDao user=new UserDao();User usera=new User();usera.setId(request.getParameter("id"));ResultSet rs=user.Select(usera);if(rs.next()){%><form action="doUpdateBean.jsp?id=<%=rs.getString("id")%>" method="post">用户名:<input type="text" value="<%=rs.getString("username") %>" name="username"><br>密 码:<input type="text" value="<%=rs.getString("password") %>" name="password"><br>用户类型:<select name="type"><option value="管理员">管理员</option><option value="普通用户">普通用户</option></select><br><input type="submit" value="提交"><input type="reset" value="取消"></form>%} %></body>
</html>6 doUpdateBean.jsp
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%@ page import="java.sql.*"%>
<%@ page import="nuc.test.user.User" %>
<%@page import="nuc.test.Dao.UserDao" %><%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><base href="<%=basePath%>"><title>My JSP 'doUpdateBean.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><%request.setCharacterEncoding("utf-8"); %><jsp:useBean id="use" class="nuc.test.user.User"><jsp:setProperty name="use" property="*"/></jsp:useBean><%UserDao user=new UserDao();//User usera=new User();use.setId(request.getParameter("id"));int rs=0;rs=user.Update(use);%><jsp:forward page="queryBean.jsp"/></body>
</html>7 接下来的下个是用来显示分页的 并且设置每页显示5条信息
Bar.jsp
用来编写分页信息
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%@ page import="java.sql.*"%>
<%@ page import="nuc.test.user.User" %>
<%@page import="nuc.test.Dao.*" %>
<%@page import="java.util.*" %><%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><base href="<%=basePath%>"><title>My JSP 'Bar.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><%int pages;int currpage=1;if(request.getParameter("page")!=null){currpage=Integer.parseInt(request.getParameter("page"));}Find find=new Find();int count=find.SelectCount();if(count%User.PAGESIZE==0){pages=count/User.PAGESIZE;}else{pages=count/User.PAGESIZE+1;}StringBuffer sb=new StringBuffer();for(int i=1;i<=pages;i++){if(i==currpage){sb.append("["+i+"]");}else{sb.append("<a href='showPage.jsp?page="+i+"'>"+i+"</a>");}sb.append(" ");}out.print(sb);request.setAttribute("bar",sb.toString());%></body>
</html>ShowPage.jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page import="java.sql.*"%>
<%@ page import="nuc.test.user.User" %>
<%@page import="nuc.test.Dao.*" %>
<%@page import="java.util.*" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><base href="<%=basePath%>"><title>My JSP 'showPage.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><table align="center" width="800" border="1"><tr><td align="center" colspan="5"><h2>所有用户信息</h2></td></tr><tr align="center"><td>用户名</td><td>密码</td><td>用户类型</td><td colspan="2">操作方法</td></tr><%int currpage=1;if(request.getParameter("page")!=null){currpage=Integer.parseInt(request.getParameter("page"));}Find find=new Find();List<User> listall=new ArrayList<User>();listall=find.Selectcontent(currpage);Iterator<User> it=listall.iterator();while(it.hasNext()){User usera=it.next();%><tr align="center"><td><%=usera.getUsername() %></td><td><%=usera.getPassword() %></td><td><%=usera.getType() %></td><td><a href="servlet/Update?id=<%=usera.getId()%>">修改</a></td><td><a href="servlet/Delete?id=<%=usera.getId()%>">删除</a></td></tr><%} %><tr><td align="center" colspan="3"><jsp:include page="Bar.jsp"/></td></tr><tr align="center"><td colspan="5"><a href="first.jsp">添加用户</a></td></tr></table></body>
</html>
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