一：主要思路
1:分页功能:
新建一个实体类，用来存储每页数据，数据量，页码，页数，下一页，上一页的相关信息。
@Data
public class PageModel<T> {
//本页数据
private List<T> pageData;
//最大数量
private Integer pageSize=2;
//第几页
private Integer pageNo;
//总记录数
private Integer count;
//获取总页数
public Integer getAllPage(){
return count%pageSize==0?count/pageSize:count/pageSize+1;
}
//判断是否有下一页
public Integer getNextPage(){
if(pageNo<getAllPage()){
return pageNo+1;
}else{
return getAllPage();
}
}
//判断是否有上一页
public Integer getPreviousePage(){
if(pageNo>1){
return pageNo-1;
}else{
return 1;
}
}分页展示代码:
<html>
<head>
<title>分页展示</title>
<link type="text/css" rel="stylesheet" href="bootstrap/css/bootstrap.css">
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-1.12.4.js" ></script>
<%-- <link href="bootstrap/static/bootstrap-3.3.7-dist/css/bootstrap.css" rel="stylesheet" />--%>
<%-- <script type="text/javascript" src="js/jquery-1.12.4.js" ></script>--%>
<script type="text/javascript" src="bootstrap/static/bootstrap-3.3.7-dist/js/npm.js" ></script>
<script>
function add(){
window.location.href="preadd.do?method=preadd";
}
function subForm(pageno){
// alert(pageno)
$("[name='pageNo']").val(pageno)//给name='pageNo'的元素赋值
$("[title='queryForm']").submit();//提交表单
// document.getElementById("form").submit();
}
</script>
<style>
#container{
padding: 10px;
}
#content{
text-align: center;
}
#page{
}
#query{
float: left;
text-align: center;
margin: 10px;
padding: 10px;
}
form{
display: flex;
}
</style>
</head>
<body>
<div id="query">
<div>
<form method="post" action="student.do?method=select" title="queryForm" name="myform">
<input type="hidden" name="pageNo" id="pageNo"/>
学生姓名：<input type="text" name="stuname" value="${param.stuname}"/>
学生住址：<input type="text" name="stuadd" value="${param.stuadd}"/>
性别：<input type="text" name="stusex" value="${param.stusex}"/>
年级:<select name="gradename">
<option value="">请选择</option>
<c:forEach items="${GAll}" var="grade">
<option value="${grade.gradename}" ${param.gradename==grade.gradename?"selected='true'":""}>${grade.gradeid}--${grade.gradename}</option>
</c:forEach>
</select>
<input type="submit" value="查询">
</form>
</div>
</div>
<div id="container">
<div style="text-align: right;margin: 10px">
<button type="button" class="btn btn-primary" id="add" onclick="add();" >添加</button>
</div>
<div id="content">
<table class="table">
<tr>
<td>学生编号</td>
<td>登录密码</td>
<td>学生姓名</td>
<td>性别</td>
<td>年级</td>
<td>电话</td>
<td>地址</td>
<td>生日</td>
<td>邮箱</td>
<td>操作</td>
</tr>
<c:forEach items="${list}" var="student">
<tr>
<td>${student.studentno}</td>
<td>${student.loginpwd}</td>
<td>${student.studentname}</td>
<td>${student.sex}</td>
<td>${student.gradeid}</td>
<td>${student.phone}</td>
<td>${student.address}</td>
<td>${student.borndate}</td>
<td>${student.email}</td>
<td>
<a href="student.do?method=preupdate&studentNo=${student.studentno}"/>修改
<a href="student.do?method=delete&studentNo=${student.studentno}"/>删除
</td>
</tr>
</c:forEach>
</table>
</div>
<div id="page">
<div style="float: left">
<nav aria-label="...">
<ul class="pager">
<li><a href="javascript:void(0)" onclick="subForm(1)">首页</a></li>
<li><a href="javascript:void(0)" onclick="subForm(${pageModel.previousePage})">上一页</a></li>
<li><a href="javascript:void(0)" onclick="subForm(${pageModel.nextPage})">下一页</a></li>
<li><a href="javascript:void(0)" onclick="subForm(${pageModel.allPage})">尾页</a></li>
</ul>
</nav>
</div>
<div style="float: right;font-size: 12px;margin-top: 25px">
共${pageModel.count}条记录 当前第${pageModel.pageNo}页 一共${pageModel.allPage}页 每页展示${pageModel.pageSize}条数据
</div>
</div>
</div>
</body>
</html>
在dao层学生类中新建两个方法，一个用来获取总记录数，一个用来获取本页数据（使用limit实现），再通过service层调用方法。
@Override
public int getCount() {
int count = Integer.parseInt( new JDBCUtils().queryOneVal("select count(1) from student").toString());
return count;
}
@Override
public List<Student> getPageData(int pageNo, int pageSize) {
return new JDBCUtils().executeQuery(Student.class,"select * from student limit ?,?",(pageNo-1)*pageSize,pageSize);
}servlet层有个list方法，页码初始值为1，随着获取页面传的页码改变，然后调用service层获取该页数据信息，传递到页面进行展示。
public void list(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
int pageNo = 1;//页码初始值为1
if(null != req.getParameter("pageNO")){
pageNo = Integer.parseInt(req.getParameter("pageNO"));//获取页面传来的页码改变
}
PageModel<Student> pageModel = new StudentService().getpageModel(pageNo);
List<Student> list = pageModel.getPageData();//获取页面数据
List<Grade> getall = new GradeService().getall();//获取年级信息
req.setAttribute("GAll",getall);
req.setAttribute("list",list);
req.setAttribute("pageModel",pageModel);
req.getRequestDispatcher("pageList.jsp").forward(req,resp);
}2：数据添加
点击添加按钮，转入后端servlet代码的preadd方法中，查询出年级信息并传到前端页面通过下拉列表展示，然后填写信息，点击提交，
public void preadd(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
GradeService gradeService = new GradeService();
List<Grade> all = gradeService.getall();
// System.out.println(all);
req.setAttribute("list",all);
req.getRequestDispatcher("addStu.jsp").forward(req,resp);
}添加页面代码
<html>
<head>
<title>Title</title>
<script type="javascript" src="js/jquery-1.12.4.js"></script>
<link type="text/css" rel="stylesheet" href="bootstrap/css/bootstrap.css">
<script>
function checkTypeid(){
var v = document.getElementsByName("booktype")[0].value;
if(v=="-1"){
alert("图书类标必须选择");
return false;
}
return true;
}
</script>
</head>
<body>
<h1>学生添加</h1>
<form method="post" action="student.do?method=add" onsubmit="return checkForm();">
<div class="form-group">
<label for="stuno">学生学号</label>
<input type="text" class="form-control" id="stuno" placeholder="stuno" name="stuno">
</div>
<div class="form-group">
<label for="stuname">学生姓名</label>
<input type="text" class="form-control" id="stuname" placeholder="stuname" name="stuname">
</div>
<div class="form-group">
<label for="stupassword">登陆密码</label>
<input type="text" class="form-control" id="stupassword" placeholder="stupassword" name="stupassword" onblur="checkBookNum()">
<span class="error"></span>
</div>
<div class="form-group">
<label for="stusex">学生性别</label>
<input type="text" class="form-control" id="stusex" placeholder="stusex" name="stusex">
</div>
<div class="form-group">
<label for="stuphone">学生电话</label>
<input type="text" class="form-control" id="stuphone" placeholder="stuphone" name="stuphone">
</div>
<div class="form-group">
<label for="stuaddress">学生住址</label>
<input type="text" class="form-control" id="stuaddress" name="stuaddress">
</div>
<div class="form-group">
<label for="stuborn">学生生日</label>
<input type="date" class="form-control" id="stuborn" name="stuborn">
</div>
<div class="form-group">
<label for="stuemail">学生邮件</label>
<input type="text" class="form-control" id="stuemail" name="stuemail">
</div>
<div class="form-group">
<label for="stuname">学生年级</label>
<select class="form-control" name="stugradeid" onchange="checkBookNum()">
<option value="-1">请选择</option>
<c:forEach items="${list}" var="grade">
<option value="${grade.gradeid}">${grade.gradeid}--${grade.gradename}</option>
</c:forEach>
</select>
</div>
<button type="submit" class="btn btn-default">保存</button>
</form>
</body>
</html>
页面提交表单，调用servlet层的add方法，该方法获取到所有参数信息，生成一个学生对象，然后调用dao层的添加方法添加学生信息，并调用list方法转到分页展示页面。
public void add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获取参数
// System.out.println(request.getParameter("StudentNo"));
StudentDao studentDao = new StudentDao();
String studentNo = request.getParameter("stuno");
String loginPwd = request.getParameter("stupassword");
String studentName = request.getParameter("stuname");
String sex = request.getParameter("stusex");
String gradeId = request.getParameter("stugradeid");
String phone = request.getParameter("stuphone");
String address = request.getParameter("stuaddress");
String bornDate = request.getParameter("stuborn");
String email = request.getParameter("stuemail");
Student student = new Student(studentNo,loginPwd,studentName,sex,Integer.parseInt(gradeId),phone,address,bornDate,email);
//插入数据
studentDao.save(student);
// System.out.println(update);
//响应页面
response.sendRedirect("student.do?method=list");
}3：数据删除
点击页面学生信息后面的删除，调用servlet层的delete方法并将学生学号传递过来，delete方法调用service层的delete方法通过学号删除该学生信息，并重新调用list方法转到数据分页展示页面。
public void delete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String studentNo = req.getParameter("studentNo");
StudentService service = new StudentService();
service.delete(studentNo);
resp.sendRedirect("student.do?method=list");
}4：数据修改
点击页面学生信息后的修改，将学生学号传递过来调用servlet层的preupdate方法，preupdate方法通过学号查询出该学生相关信息，并通过GradeService查询出所有的年级信息，传输该数据到数据修改页面，默认值为修改前的值。然后用户修改完后调用service层的update方法通过学号修改该学生信息，并重新调用list方法转到数据分页展示页面。
public void preupdate(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获取参数
String studentNo = request.getParameter("studentNo");
// System.out.println(studentNo);
StudentService studentService = new StudentService();
Student student = studentService.selectOne(studentNo);
GradeService gradeService = new GradeService();
List<Grade> getall = gradeService.getall();
// System.out.println(getall);
// request.setAttribute("gradename",gradename);
request.setAttribute("GAll",getall);
request.setAttribute("student",student);
// System.out.println(student);
//响应页面
request.getRequestDispatcher("update.jsp").forward(request,response);
} public void update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获取参数
Student student = new Student();
student.setStudentno(request.getParameter("stuno"));
student.setStudentname(request.getParameter("stuname"));
student.setLoginpwd(request.getParameter("stupassword"));
student.setSex(request.getParameter("stusex"));
student.setPhone(request.getParameter("stuphone"));
student.setAddress(request.getParameter("stuaddress"));
student.setBorndate(request.getParameter("stuborn"));
student.setEmail(request.getParameter("stuemail"));
student.setGradename(request.getParameter("gradename"));
String name = request.getParameter("gradename");
Grade grade = new GradeService().findOneByName(name);
student.setGradeid(grade.getGradeid());
System.out.println(student);
StudentService studentService = new StudentService();
studentService.update(student);
//响应页面
response.sendRedirect("student.do?method=list");
}修改页面代码：
<html>
<head>
<title>更新</title>
</head>
<body>
<h1>信息修改</h1>
<form method="post" action="student.do?method=update">
<div class="form-group">
<label for="stuno">学生学号</label>
<input type="text" class="form-control" id="stuno" value="${student.studentno}" name="stuno">
</div>
<div class="form-group">
<label for="stuname">学生姓名</label>
<input type="text" class="form-control" id="stuname" value="${student.studentname}" name="stuname">
</div>
<div class="form-group">
<label for="stupassword">登陆密码</label>
<input type="text" class="form-control" id="stupassword" value="${student.loginpwd}" name="stupassword" onblur="checkBookNum()">
<span class="error"></span>
</div>
<div class="form-group">
<label for="stusex">学生性别</label>
<input type="text" class="form-control" id="stusex" value="${student.sex}" name="stusex">
</div>
<div class="form-group">
<label for="stuphone">学生电话</label>
<input type="text" class="form-control" id="stuphone" value="${student.phone}" name="stuphone">
</div>
<div class="form-group">
<label for="stuaddress">学生住址</label>
<input type="text" class="form-control" id="stuaddress" value="${student.address}" name="stuaddress">
</div>
<div class="form-group">
<label for="stuborn">学生生日</label>
<input type="date" class="form-control" id="stuborn" value="${student.borndate}" name="stuborn">
</div>
<div class="form-group">
<label for="stuemail">学生邮件</label>
<input type="text" class="form-control" id="stuemail" value="${student.email}" name="stuemail">
</div>
<div class="form-group">
<label for="gradename">学生年级</label>
<select class="form-control" id="gradename" name="gradename">
<option value="">请选择</option>
<c:forEach items="${GAll}" var="grade">
<option value="${grade.gradename}" ${student.gradename==grade.gradename?"selected='true'":""}>${grade.gradeid}--${grade.gradename}</option>
</c:forEach>
</select>
</div>
<button type="submit" class="btn btn-default">保存</button>
</form>
</body>
</html>
数据查询（条件查询）：
通过输入查询条件然后点击查询后服务端执行servlet层的select方法,该方法调用service层的getall、getpagedata方法来获取符合条件的记录数及相关数据，保存并发送到页面。后续点击切换页码也执行该方法查询符合条件的数据并传输展示。
//条件查询
//获取符合条件的总记录数
@Override
public int getCount(stuCondition stuCondition) {
StringBuilder stringBuilder = new StringBuilder("select count(1) from student s left join grade g on s.GradeId = g.GradeId where 1 = 1");
List<Object> list = new ArrayList<>();
appendCons(stringBuilder,list,stuCondition);
Object o = new JDBCUtils().queryOneVal(stringBuilder.toString(), list.toArray());
return Integer.parseInt(o.toString());
}
//根据页码获取本页数据
@Override
public List<Student> getPageData(stuCondition stuCondition, int pageNo, int pageSize) {
StringBuilder stringBuilder = new StringBuilder("select s.*,g.GradeName from student s left join grade g on s.GradeId = g.GradeId where 1 = 1");
List<Object> list = new ArrayList<>();
appendCons(stringBuilder,list,stuCondition);
stringBuilder.append(" limit ?,?");
list.add((pageNo-1)*pageSize);
list.add(pageSize);
// System.out.println(stringBuilder);
return new JDBCUtils().executeQuery(Student.class,stringBuilder.toString(),list.toArray());
}
//辅助方法（条件拼接）
public void appendCons(StringBuilder stringBuilder,List<Object> params,stuCondition stuCondition){
if(StringUtils.Stringjudge(stuCondition.stuname)){
stringBuilder.append(" and StudentName like ?");
params.add("%"+stuCondition.stuname+"%");
}
if(StringUtils.Stringjudge(stuCondition.stuadd)){
stringBuilder.append(" and Address = ?");
params.add(stuCondition.stuadd);
}
if(StringUtils.Stringjudge(stuCondition.stusex)){
stringBuilder.append(" and Sex = ?");
params.add(stuCondition.stusex);
}
if(StringUtils.Stringjudge(stuCondition.gradeName)){
stringBuilder.append(" and GradeName = ?");
params.add(stuCondition.gradeName);
}
} public void select(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{
// System.out.println("select方法进入！");
stuCondition condition = new stuCondition();
// System.out.println(req.getParameter("stuname"));
condition.setStuname(req.getParameter("stuname"));
condition.setStuadd( req.getParameter("stuadd"));
condition.setStusex(req.getParameter("stusex"));
condition.setGradeName(req.getParameter("gradename"));
System.out.println(req.getParameter("gradename"));
System.out.println(condition);
int pageNo=1;
String pageNoStr = req.getParameter("pageNo");
if(StringUtils.Stringjudge(pageNoStr)){
pageNo = Integer.parseInt(pageNoStr);
}
System.out.println("当前页码"+pageNo);
PageModel<Student> pageModel = new StudentService().getPageModel(condition,pageNo);
// System.out.println(pageModel);
List<Student> list = pageModel.getPageData();
List<Grade> getall = new GradeService().getall();
req.setAttribute("GAll",getall);
req.setAttribute("list",list);
req.setAttribute("pageModel",pageModel);
req.getRequestDispatcher("pageList.jsp").forward(req,resp);
}效果展示：
查询：
增加：
删除：（name=人工费）
修改：（学号为s2004的学生）
