Java简单示例-用户登录、单个页面的增删改查及简单分页

 index.html  -登录->stulist.jsp （index.html传递到LoginServlet，进行登录检测及写入session，NO返回index.html界面，OK 跳转到stulist.jsp）

stulist.jsp 实现对学生的增删改查及分页.(stulist.jsp检测是否有session，以及student列表中是否有学生信息，没有session返回index页面，student列表中没有信息调用GetStudentServlet获取学生信息，获取过程中已分页)

数据库操作类详见：http://www.cnblogs.com/A--Q/p/6137525.html

 stulist.jsp界面如下：

查询：可以实现组合查询，输入条件，点击‘查询’即可

增加：在上方输入完整学生信息后，选择‘添加’选项按钮，添加可用，点击‘添加’，即将刚才填写的学生信息，增加的数据库中

删除：在要删除的学生后点击‘删除’，弹出‘询问框’，是否要删除该学生信息，选择‘是’从数据库中删除该学生，选择‘否’取消对该学生的删除操作。

修改：在要修改的学生后点击‘修改’，表格上方，显示一排信息框，除学号外，填写好更改的信息，点击更新，即可，或者点击‘取消’，取消本次的更新。

（如果删除了该学生，则该页面会刷新，上方的更新框会隐藏，即不会存在逻辑性错误）。

对于分页：

 这里没有让用户输入每页显示多少条信息，而是笔者自己再代码中写好的，每页显示10条，如果没有条件则显示如下：

如果加上条件，则显示为：

在stulist.jsp 页面中共有两个表单，一个表单传入到 GetStudentServlet 执行stulist.jsp传入的数据进行分页跳转，插入输入，查询数据，flag=3 分页跳转 flag=2插入 flag=1查询，一个表单传入到GetStudentServlet_extend 执行stulist.jsp传入的数据进行删除和修改数据，flag=1 删除 flag=2修改

以上两个Servlet操作完后都会返回student数组列表对象在stulist显示。（使用StudentDao对象得到student数组列表）

StudentDao:

package com.mis.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import com.mis.bean.Student;

public class StudentDao extends DBOper{
    public ArrayList<Student> getStudent(int flag,String parameter,int crrentPage){//分页查询
        String sql="select id,stuno,name,sex,age,major from student order by id desc";
        if (flag>0) {
            sql= "select * from student where "+parameter;
        }
        crrentPage=(crrentPage==0?0:crrentPage-1);
        sql+=" limit "+crrentPage*10+",10";//默认每页显示
        ArrayList<Student> students = new ArrayList<Student>();
        ResultSet rs = executeQuery(sql,null);
        try {
            while(rs.next()){
                Student s = new Student();
                s.setId(rs.getInt("id"));
                s.setStuno(rs.getString("stuno"));
                s.setName(rs.getString("name"));
                s.setSex(rs.getString("sex"));
                s.setAge(rs.getInt("age"));
                s.setMajor(rs.getString("major"));
                students.add(s);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return students;    
    }
    public int getStudentCount(int flag,String parameter){//得到查询的总条数
        String sql="select id,stuno,name,sex,age,major from student";
        if (flag>0) {
            sql= "select * from student where "+parameter;
        }
        ResultSet rs = executeQuery(sql,null);
        try {
            rs.last();
            return rs.getRow();
        } catch (SQLException e) {
            return 0;
        }
    }
    public ArrayList<Student> getStudent(int flag,String parameter){//未分页查询
        String sql="select id,stuno,name,sex,age,major from student order by id";
        if (flag>0) {
            sql= "select * from student where "+parameter;
        }
        ArrayList<Student> students = new ArrayList<Student>();
        ResultSet rs = executeQuery(sql,null);
        try {
            while(rs.next()){
                Student s = new Student();
                s.setId(rs.getInt("id"));
                s.setStuno(rs.getString("stuno"));
                s.setName(rs.getString("name"));
                s.setSex(rs.getString("sex"));
                s.setAge(rs.getInt("age"));
                s.setMajor(rs.getString("major"));
                students.add(s);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return students;    
    }
    public int addDelUp(String sql) {
        int num=0;
        num=executeUpdate(sql,null);
        if(num!=0)return num;
        return 0;
    }    
}

GetStudentServlet_extend

package com.mis.servlet;

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

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.mis.bean.Student;
import com.mis.dao.StudentDao;

public class GetStudentServlet_extend extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public GetStudentServlet_extend() {
        super();
    }

    // 执行stulist.jsp传入的数据进行删除和修改数据，flag=1 删除 flag=2修改
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        ServletContext ctx = this.getServletContext();
        String server = ctx.getInitParameter("server");
        String dbname = ctx.getInitParameter("dbname");
        String user = ctx.getInitParameter("user");
        String pwd = ctx.getInitParameter("pwd");
        StudentDao dao = new StudentDao();
        String sql = null;
        int flag = 0;
        try {
            flag = Integer.parseInt(request.getParameter("flag_delUp"));
        } catch (Exception e) {
            flag = 0;
        }
        String stuid = request.getParameter("ud");
        String stuname = request.getParameter("ud_name");
        String stusex = request.getParameter("ud_sex");
        String stuage = request.getParameter("ud_age");
        String stumajor = request.getParameter("ud_major");
        String del_stuid = request.getParameter("parameter_del");
        if (flag == 1) {// 执行删除
            try {
                flag = 0;
                sql = "Delete from student where stuno='" + del_stuid + "';";
                dao.getConn(server, dbname, user, pwd);
                dao.addDelUp(sql);
            } catch (Exception e) {
                e.printStackTrace();
            }
        } else if (flag == 2) {// 执行修改
            flag = 0;
            sql = "update student set name='" + stuname + "',sex='" + stusex + "',age='" + stuage + "',major='"
                    + stumajor + "' where stuno='" + stuid + "';";
            try {
                dao.getConn(server, dbname, user, pwd);
                dao.addDelUp(sql);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        try {
            dao.getConn(server, dbname, user, pwd);
            ArrayList<Student> students = dao.getStudent(0, null, 0);
            request.setAttribute("stuCount", dao.getStudentCount(0, null));
            request.setAttribute("students", students);
            request.setAttribute("currentPage", 1);//默认用户打开的分页第一页
            request.getRequestDispatcher("stulist.jsp").forward(request, response);
            return;
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
}

stulist.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page import="java.util.*"%>
<%@ page import="java.lang.Math"%>
<%@ page import="com.mis.bean.Student"%>
<%@ page import="com.mis.dao.DBOper"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt"%>
<!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>学生信息列表</title>

<script src="js_jquery/stulist.js" charset="UTF-8"></script>
<link rel="stylesheet" href="css/stulist.css">
</head>
<body>
    <c:if test="${username==null }">
        <jsp:forward page="index.html"></jsp:forward>
    </c:if>
    <c:if test="${students==null}">
        <jsp:forward page="getStudent"></jsp:forward>
    </c:if>

    <table border="0" align="center" cellspacing="0" class="list_table"
        id="senfe" style=' 90%'>
        <thead>
            <tr>
                <td colspan='7'>
                    <form method="POST" name="form" action="getStudent">
                        <!-- 开发阶段 没有对用户的非法输入进行过滤-->
                        <input type="hidden" name="flag" value="1"> <input
                            type="text" name="stuid" value="学号"
                            onclick="if(this.value == '学号')this.value ='';"
                            onBlur="if(this.value == ' '||this.value == '')this.value ='学号';">
                        <input type="text" name="stuname" value="姓名"
                            onclick="if(this.value == '姓名')this.value ='';"
                            onBlur="if(this.value == ' '||this.value == '')this.value ='姓名';">
                        <input type="text" name="stusex" value="性别"
                            onclick="if(this.value == '性别')this.value ='';"
                            onBlur="if(this.value == ' '||this.value == '')this.value ='性别';">
                        <input type="text" name="stuage" value="年龄"
                            onclick="if(this.value == '年龄')this.value ='';"
                            onBlur="if(this.value == ' '||this.value == '')this.value ='年龄';">
                        <input type="text" name="stumajor" value="专业"
                            onclick="if(this.value == '专业')this.value ='';"
                            onBlur="if(this.value == ' '||this.value == '')this.value ='专业';">
                        <input type="radio" name="selAdd" checked onclick="selop()">
                        <input type="submit" value="查询" id="selcon"> <input
                            type="radio" name="selAdd" onclick="selop()"><input
                            type="submit" disabled value="增加" id="addcon" onclick="setPar()">
                    </form>
                </td>
            </tr>
            <tr>
                <th>学号</th>
                <th>姓名</th>
                <th>性别</th>
                <th>年龄</th>
                <th>专业</th>
                <th>删除</th>
                <th>修改</th>
            </tr>
        </thead>
        <tbody>
            <form method="post" name="DelUp" action="getStudent_extend">
                <c:forEach var="student" items="${students }">
                    <tr align="center">
                        <td>${student.stuno }</td>
                        <td>${student.name }</td>
                        <td>${student.sex }</td>
                        <td>${student.age }</td>
                        <td align="left">${student.major }</td>
                        <td><input type="submit" name=${student.stuno } value="删除"
                            onclick="del(this)"></td>
                        <td><input type="button" name=${student.stuno } value="修改"
                            onclick="updata(this)"></td>
                    </tr>
                </c:forEach>
                
                    <div id="updateDiv">
                    学号：<input type="text" name="ud" readOnly>
                    姓名：<input type="text" name="ud_name">
                    性别：<input type="text" name="ud_sex">
                    年龄：<input type="text" name="ud_age">
                    专业：<input type="text" name="ud_major">
                    
                    <input type="submit" value="更新">
                    <span id="cancelUpdate" onclick="cancelupdate()">取消</span>
                    </div>
                    
                <input type="hidden" name="flag_delUp"> <input type="hidden"
                    name="parameter_del">
            </form>
        </tbody>
    </table>
    <div id="pageCount" style="600px;margin-left:auto;margin-right:auto;">
        <c:if test="${stuCount!=null}">
            <br /><c:if test="${condition!=null&&condition!=''}">查询条件为<c:out value="${condition}"></c:out></c:if>
            <c:out value="${stuCount}"></c:out>条记录,<!-- Math.ceil() 向上取整  -- (stuCount-((stuCount-1)%10))/10+1 ** -->
            共<fmt:formatNumber type="number" value="${(stuCount-((stuCount-1)%10))/10+1}" maxFractionDigits="0"/>页
            ,当前为第<c:out value="${currentPage}"></c:out>页
        
        <form method="post" name="paging" action="getStudent">
            <input type="text" value="" name="page" onkeyup="this.value=this.value.replace(/D/g,'')" onafterpaste="this.value=this.value.replace(/D/g,'')">
            <input type="hidden" name="flag" value="3">
            <input type="hidden" name="parame" value='<c:out value="${condition}"></c:out>'>
             <input    type="submit" value="跳转" onclick="checkPage()">
        </form>
    </c:if>
    </div>
</body>
</html>

 源代码：https://pan.baidu.com/s/1e_mTr1Rf4BoehNBwDEg76g 密码：8qg3