上一次的文章，我们讲解了如何用JAVA访问MySql数据库，对数据进行增加删除修改查询。那么这次我们把具体的页面的数据库操作结合在一起，进行一次简单的学生信息操作案例。
首先我们创建一个专门用于学生管理的ManageServlet。
接着我们需要一个展现数据的页面，也就是 UserList.jsp
<%@page import="com.babybus.sdteam.vo.Student"%>
<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<%
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>学生信息管理</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>
<%=basePath %>
<table border="1" width="100%" >
<tr>
<th>uid</th>
<th>学生姓名</th>
<th>年龄</th>
<th>班级</th>
<th>操作</th>
</tr>
<%
// 获取学生列表数据
List<Student> lsUser=(List)request.getAttribute("students");
if(lsUser==null||lsUser.size()==0){
pageContext.setAttribute("theUser","1");
}else{
// 遍历列表生成表格数据
for(int i=0;i<lsUser.size();i++){
pageContext.setAttribute("theUser",lsUser.get(i));
%>
<tr>
<td>${theUser.id}</td>
<td>${theUser.studentname}</td>
<td>${theUser.age}</td>
<td>${theUser.classname}</td>
<td>
<a href="AddUser.jsp?id=${theUser.id}">修改<a/>|
<a href="Mangage?method=del&userid=${theUser.id}" onclick="return confirm('确定要删除么？')" }>删除</a>
</td>
</tr>
<%
}
}
%>
</table>
<a href="AddUser.jsp">增加<a/>
</body>
</html>
接下来我们需要一个进行增加修改的页面AddUser.jsp
<%@page import="com.babybus.sdteam.bo.ManageServlet"%>
<%@page import="com.babybus.sdteam.vo.Student"%>
<%@page import="com.babybus.sdteam.bo.LoginServlet"%>
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
response.setContentType("text/html;charset=UTF-8");
request.setCharacterEncoding("UTF-8");
%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'AddUser.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="学生信息管理">
<link rel="stylesheet" type="text/css" href="styles.css">
</head>
<body>
<%
String id= request.getParameter("id");
if(id!=null){
ManageServlet loginServlet =new ManageServlet();
Student student = loginServlet.getStudentById(id);
pageContext.setAttribute("theUser",student);
pageContext.setAttribute("method","update");
pageContext.setAttribute("title","修改");
}
else{
pageContext.setAttribute("method","add");
pageContext.setAttribute("title","添加");
}
%>
<form action="Mangage?method=${method}" method="post" >
<input type="hidden" name="userid" value="${theUser.id}">
<table width="100%" height="200px" border="1">
<tr>
<td colspan="2">${title}</td>
</tr>
<tr>
<td align="right">学生名</td>
<td>
<input type="text" name="studentname" value="${theUser.studentname}">
</td>
</tr>
<tr>
<td align="right">年龄:</td>
<td>
<input type="text" name="age" value="${theUser.age}">
</td>
</tr>
<tr>
<td align="right">班级:</td>
<td>
<input type="text" name="classname" value="${theUser.classname}">
</td>
</tr>
<tr>
<td colspan='2' align="center">
<input type="submit" value="保存" name="btnSubmit">
<input type="reset" value="重置" name="btnCancel">
</td>
</tr>
</table>
</form>
</body>
</html>
有了页面支撑，我们需要后台的Servlet进行数据处理转发
/**
* 业务处理
* @param req
* @param rep
* @throws IOException
* @throws ServletException
*/
public void process(HttpServletRequest req,HttpServletResponse rep) throws ServletException, IOException {
String method = req.getParameter("method");
System.out.println("操作:" + method);
Student student = new Student();
if(!"del".equals(method)) {
// 进行编码转换，避免中文乱码
String studentname = new String(req.getParameter("studentname").getBytes("ISO-8859-1"),"utf-8");
int age = Integer.parseInt(req.getParameter("age"));
String classname = new String(req.getParameter("classname").getBytes("ISO-8859-1"),"utf-8");
student.setStudentname(studentname);
student.setAge(age);
student.setClassname(classname);
} StudentDao dao = new StudentDao();
// 修改
if("update".equals(method)) {
String id = req.getParameter("userid");
student.setId(Integer.parseInt(id));
try {
dao.updateStudent(student);
} catch (SQLException e) {
e.printStackTrace();
}
}
// 增加
else if("add".equals(method)) {
try {
dao.insertStudent(student);
} catch(SQLException e) {
e.printStackTrace();
}
}
// 删除
else if("del".equals(method)) {
try {
String id = req.getParameter("userid");
dao.deleteStudent(Integer.parseInt(id));
}catch (SQLException e) {
e.printStackTrace();
}
} ManageServlet manageservlet = new ManageServlet();
// 获取全部列表
List<Student> resultlist = manageservlet.getStudentByCondition(null);
req.setAttribute("students", resultlist);
RequestDispatcher dispatcher = req.getRequestDispatcher("UserList.jsp");
dispatcher.forward(req, rep);
}
上面就是全部的增加删除修改的代码。下面给出两个页面的截图效果
通过上面的例子我们就可以很好的掌握了J2EE的入门
结语
- 受益，掌握了J2EE的入门
本站文章为宝宝巴士 SD.Team原创，转载务必在明显处注明：（作者官方网站：宝宝巴士)
转载自【宝宝巴士SuperDo团队】 原文链接: http://www.cnblogs.com/superdo/p/4579275.html