MVC全名是Model View Controller，是模型(model)－视图(view)－控制器(controller)的缩写，一种软件设计典范，用一种业务逻辑、数据、界面显示分离的方法组织代码，将业务逻辑聚集到一个部件里面，在改进和个性化定制界面及用户交互的同时，不需要重新编写业务逻辑。MVC被独特的发展起来用于映射传统的输入、处理和输出功能在一个逻辑的图形化用户界面的结构中。
MVC指MVC模式的某种框架，它强制性的使应用程序的输入、处理和输出分开。使用MVC应用程序被分成三个核心部件：模型、视图、控制器。它们各自处理自己的任务。最典型的MVC就是JSP + servlet + javabean的模式。
学生信息管理：增、删、改、查
实现过程：Controller-servlet View-jsp Model-javaBean
代码：
需要导入Tomcat 和SQL Server驱动-sqljdbc.jar，并对web.xml文件做配置
运行界面：
web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>MVC</display-name>
<!-- DeleteServlet配置 -->
<servlet>
<servlet-name>DeleteServlet</servlet-name>
<servlet-class>com.DeleteServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>DeleteServlet</servlet-name>
<url-pattern>/DeleteServlet</url-pattern>
</servlet-mapping>
<!-- SaveServlet配置 -->
<servlet>
<servlet-name>SaveServlet</servlet-name>
<servlet-class>com.SaveServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>SaveServlet</servlet-name>
<url-pattern>/SaveServlet</url-pattern>
</servlet-mapping>
<!-- 过滤器配置 -->
<filter>
<filter-name>MyFilter</filter-name>
<filter-class>com.MyFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>GBK</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>MyFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- 主页面 -->
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>javabean的学生类：Student.java
package com;
public class Student {
private String sno;
private String sname;
public String getSno(){
return sno;
}
public void setSno(String sno){
this.sno=sno;
}
public String getSname(){
return sname;
}
public void setSname(String sname){
this.sname=sname;
}
//默认构造方法
public Student(){
}
//构造方法
public Student(String sno,String sname){
super();
this.sno=sno;
this.sname=sname;
}
//重写toString,输出所有属性的值
@Override
public String toString() {
String s="";
s+=sno+" "+sname;
return s;
}
}
javaBean的学生表的数据库操作类：StudentDao.java
package com;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
public class StudentDao {
//学生表的数据库操作类
//添加
public int insert(Student stu){
int rtn=0;//表示数据是否插入成功
try{
//连接数据库
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection con=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=Student","lkc","123456");
//得到数据库操作对象
PreparedStatement ps=con.prepareStatement(
"insert into student(sno,sname) values (?,?)"
);
//写入数据
ps.setString(1, stu.getSno());
ps.setString(2, stu.getSname());
//数据提交
rtn=ps.executeUpdate();
ps.close();
con.close();
}catch(Exception e){
e.printStackTrace();
rtn=-1;
}
return rtn;
}//添加结束
//删除
public int delete(String sno){
int rtn=0;//表示数据是否插入成功
try{
//连接数据库
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection con=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=Student","lkc","123456");
// System.out.println("success");
//得到数据库操作对象
PreparedStatement ps=con.prepareStatement(
"delete student where sno=?"
);
//写入数据
ps.setString(1, sno);
//数据提交
rtn=ps.executeUpdate();
ps.close();
con.close();
}catch(Exception e){
e.printStackTrace();
rtn=-1;
}
return rtn;
}//删除结束
//修改
public int update(Student stu){
int rtn=0;
try{
//连接数据库
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection con=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=Student","lkc","123456");
//得到数据库操作对象
PreparedStatement ps=con.prepareStatement(
"update student set sname=? where sno=?"
);
//写入数据
ps.setString(1, stu.getSname());
ps.setString(2, stu.getSno());
//数据提交
rtn=ps.executeUpdate();
ps.close();
con.close();
}catch(Exception e){
e.printStackTrace();
rtn=-1;
}
return rtn;
}//修改结束
//查询单条记录
public Student select(String sno){
Student rtn=null;
try{
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection con=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=Student","lkc","123456");
PreparedStatement ps=con.prepareStatement(
"select *from student where sno=?"
);
ps.setString(1, sno);
ResultSet rs=ps.executeQuery();
if(rs!=null&&rs.next()){
rtn=new Student();
rtn.setSno(sno);
rtn.setSname(rs.getString("Sname"));
}
rs.close();
ps.close();
con.close();
}catch(Exception e){
e.printStackTrace();
}
return rtn;
}//查询单条记录结束
//查询所有记录
public List<Student> selectAll(){
List<Student> rtn=null;
try{
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection con=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=Student","lkc","123456");
Statement st=con.createStatement();
ResultSet rs=st.executeQuery(
"select *from student"
);
if(rs!=null){
rtn=new ArrayList<Student>();
while(rs.next()){
Student stu=new Student();
stu.setSno(rs.getString("sno"));
stu.setSname(rs.getString("sname"));
rtn.add(stu);
}
}
rs.close();
st.close();
con.close();
}catch(Exception e){
e.printStackTrace();
}
return rtn;
}//查询所有记录结束
}
主界面：index.jsp
<%@page import="com.Student"%>
<%@page import="java.util.List"%>
<%@page import="com.StudentDao"%>
<%@ page language="java" contentType="text/html; charset=GB18030"
pageEncoding="GB18030"%>
<!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=GB18030">
<title>Insert title here</title>
</head>
<body>
学生信息表
<br>
<%
//调用模式层StudentDao,得到List
StudentDao sd=new StudentDao();
List<Student> ls=sd.selectAll();
if(ls!=null){
//遍历输出
for(Student stu:ls){
out.print("sno="+stu.getSno()+" ");
out.print("sname="+stu.getSname()+" ");
out.print("<a href='Update.jsp?sno="+stu.getSno()+"'>修改</a> <a href='DeleteServlet?sno="+stu.getSno()+"'> 删除</a> <br>");
}
}
%>
<br>
插入学生信息
<br>
<form action="SaveServlet" method="post">
学号:<input type="text" name="sno"><br>
姓名:<input type="text" name="sname"><br>
<input type="submit" value="提交"><br>
</form>
</body>
</html>更新页面 Update.jsp
<%@page import="com.Student"%>
<%@page import="com.StudentDao"%>
<%@ page language="java" contentType="text/html; charset=GB18030"
pageEncoding="GB18030"%>
<!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=GB18030">
<title>修改学生信息</title>
</head>
<body>
<%
String sno=request.getParameter("sno");
String sname="";
if(sno!=null && sno.trim().length()!=0){
StudentDao sd=new StudentDao();
//得到实体类
Student stu=sd.select(sno);
sname=stu.getSname();
}
else{
out.print("请正确访问！");
}
%>
<br>
修改学生信息
<br>
<form action="SaveServlet" method="post">
学号:<input type="text" name="sno" value="<%=sno %>"><br>
姓名:<input type="text" name="sname" value="<%=sname %>"><br>
<input type="hidden" name="isupdate" value="1">
<input type="submit" value="提交"><br>
</form>
</body>
</html>执行更新或插入的servlet：SaveServlet.java
package com;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class SaveServlet
*/
@WebServlet("/SaveServlet")
public class SaveServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public SaveServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//接收参数
String sno=request.getParameter("sno");
String sname=request.getParameter("sname");
//是否更新
String isupdate=request.getParameter("isupdate");
//验证
if(sno!=null && sno.trim().length()!=0 && sname!=null &&sname.trim().length()!=0){
//调用模式层
StudentDao sd=new StudentDao();
Student stu=new Student(sno,sname);
int rtn=-1;
//判断是insert还是update
//update
if(isupdate!=null && isupdate.equals("1")){
rtn=sd.update(stu);
}//update结束
//insert
else{
rtn=sd.insert(stu);
}//insert结束
if(rtn>0){
response.getWriter().write("保存成功!");
response.setHeader("refresh", "3;index.jsp");
}
else{
response.getWriter().write("保存失败!");
response.setHeader("refresh", "3;index.jsp");
}
}//if结束
else{
response.getWriter().write("请正确提交数据!");
response.setHeader("refresh", "3;index.jsp");
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
执行删除的servlet：DeleteServlet.java
package com;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class DeleteServlet
*/
@WebServlet("/DeleteServlet")
public class DeleteServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public DeleteServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String sno=request.getParameter("sno");
if(sno!=null&&sno.trim().length()!=0){
StudentDao sd=new StudentDao();
if(sd.delete(sno)>=0){
response.getWriter().write("删除成功！");
response.setHeader("refresh", "3;index.jsp");
}
else{
response.getWriter().write("删除失败！");
response.setHeader("refresh", "3;index.jsp");
}
}
else{
response.getWriter().write("请正确提交数据！");
response.setHeader("refresh", "3;index.jsp");
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
过滤器进行字符编码：MyFilter.java
package com;
import java.io.IOException;
import javax.servlet.*;
public class MyFilter implements Filter{
// 字符编码
private String encoding;
public MyFilter() {
// TODO Auto-generated constructor stub
}
@Override
public void destroy() {
// TODO Auto-generated method stub
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
// TODO Auto-generated method stub
// 获取字符编码
encoding = filterConfig.getInitParameter("encoding");
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
// TODO Auto-generated method stub
// 判断字符编码是否有效
if (encoding != null) {
// 设置request字符编码
request.setCharacterEncoding(encoding);
// 设置response字符编码
response.setContentType("text/html; charset="+encoding);
}
chain.doFilter(request, response);
}
}