标签：war .sql 修改 Servle 小型 url 作用 .exe slist
1.什么是MVC
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。
（1）Model层：Model指模型部分，一般在应用中Model层包括业务处理层和数据访问层。数据访问层主要是对数据库的一些操作的封装。业务处理层应用JavaBean构建， JavaBean主要是用作将从View层获取的数据和数据库的数据进行桥接。除却JavaBean以外，若想构建分布式应用系统，可以应用EJB组件进行业务逻辑层的构建。
（2）Controller层：Controller指控制部分，一般是对View层提交的请求为其设置对应的Servlet进行特定功能的处理，这里的进行特定功能的处理一般是编写在Model中的业务处理层中的。Controller一般只是在Web应用中充当一个中介者的作用。
（3）View层：View指视图部分，这一部分的内容是展示给用户实际进行交互的，通常使用JSP和HTML进行构建（个人比较喜欢以HTML嵌入JSP的方式来构建网页）。
综上来说，一个小型完整的基于MVC设计模式的Web应用程序的处理流程应该如下：
由上面的图中我们可以看出，用户在客户端（Web应用的客户端即为浏览器）中发出请求的时候，请求首先由View层的JSP/HTML将HTTP请求传给控制器中对应的Servlet，然后由Servlet负责调用Model层中的业务逻辑处理部分进行要求的处理，处理期间如果设计数据库的操作，则与数据库进行操作，最后全部操作结束之后，由业务逻辑层将结果发给控制层，控制层以HTTP响应的形式将结果发送回客户端。
MVC编程模式
package bean;
public class News {
String title;
String datetime;
String content;
String type;
int id;
public News(String title,String datetime,String content,String type,int id){
super();
this.title = title;
this.datetime = datetime;
this.content = content;
this.type = type;
this.id = id;
}
public int getId(){
return id;
}
public void setId(int id){
this.id = id;
}
public News(){
}
public String getTitle(){
return title;
}
public void setTitle(String title){
this.title = title;
}
public String getDatetime(){
return datetime;
}
public void setDatetime(String datetime){
this.datetime = datetime;
}
public String getContent(){
return content;
}
public void setContent(String content){
this.content = content;
}
public String getType(){
return type;
}
public void setType(String type){
this.type = type;
}
public News(String title,String datetime,String content,String type){
super();
this.title = title;
this.datetime = datetime;
this.content = content;
this.type = type;
}
}
News.java
package bean;
public class User {
String name;
String password;
public User(){
}
public String getName(){
return name;
}
public void setName(String name){
this.name = name;
}
public String getPassword(){
return password;
}
public void setPassword(String password){
this.password = password;
}
public User(String name,String password){
super();
this.name = name;
this.password = password;
}
}
User.java
package com.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import bean.News;
public class Newsdao {
@SuppressWarnings("unused")
private static final long serialVersionUID = 1L;
static Connection con = null;
public static Connection getCon(){
String driverName = "com.mysql.cj.jdbc.Driver";
String url = "jdbc:mysql://localhost:3306/newsdata?useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=true";
String name = "root";
String pwd = "123456";
try{
Class.forName(driverName);
try{
con = DriverManager.getConnection(url,name,pwd);
}catch(SQLException e){
e.printStackTrace();
}
}catch(ClassNotFoundException e){
e.printStackTrace();
}
return con;
}
//添加新闻
public boolean addNews(News news){
con = Newsdao.getCon();
boolean flag = false;
String sql = "insert news(title,type,datetime,content) values(‘"+news.getTitle()+"‘,‘"+news.getType()+"‘,‘"+news.getDatetime()+"‘,‘"+news.getContent()+"‘)";
try{
PreparedStatement ps = con.prepareStatement(sql);
int i = ps.executeUpdate();
ps.close();
con.close();
if(i>0){
flag = true;
}
}catch(SQLException e){
System.out.println("添加出错！");
e.printStackTrace();
}
return flag;
}
public List<News> selectByID(int id){
con = Newsdao.getCon();
List<News> list = new ArrayList<>();
String sql = "select * from news where id="+id+"";
System.out.println(sql);
Statement state;
ResultSet rs;
try{
state = con.createStatement();
rs = state.executeQuery(sql);
while(rs.next()){
News news = new News();
news.setTitle(rs.getString("title"));
news.setDatetime(rs.getString("content"));
news.setContent(rs.getString("content"));
news.setType(rs.getString("type"));
news.setId(id);
list.add(news);
}
rs.close();
state.close();
con.close();
}catch(SQLException e){
System.out.println("查询出错！");
e.printStackTrace();
}
return list;
}
//删除新闻
public List<News> selectAll(){
con = Newsdao.getCon();
List<News> list = new ArrayList<News>();
String sql = "select * from news";
Statement state;
ResultSet rs;
try{
state = con.createStatement();
rs = state.executeQuery(sql);
while(rs.next()){
News news = new News();
news.setId(rs.getInt("id"));
news.setTitle(rs.getString("title"));
news.setDatetime(rs.getString("datetime"));
news.setContent(rs.getString("content"));
news.setType(rs.getString("type"));
list.add(news);
}
rs.close();
state.close();
con.close();
}catch(SQLException e){
System.out.println("查询出错！");
e.printStackTrace();
}
return list;
}
//修改新闻
public boolean update(News news){
con = Newsdao.getCon();
boolean flag = false;
String sql = "update news set title=‘"+news.getTitle()+"‘,type=‘"+news.getType()+"‘,datetime=‘"+news.getDatetime()+"‘,content=‘"+news.getContent()+"‘ where id = "+news.getId()+"";
System.out.println(sql);
Statement state = null;
try{
state = con.createStatement();
int i=state.executeUpdate(sql);
System.out.println(i);
if(i>0){
flag = true;
}
}catch(SQLException e){
System.out.println("更新错误！");
e.printStackTrace();
}
return flag;
}
//删除新闻
public boolean delete(int id){
con = Newsdao.getCon();
boolean flag = false;
String sql = "delete from news where id=‘"+id+"‘";
PreparedStatement ps;
try{
ps = con.prepareStatement(sql);
int i = ps.executeUpdate();
if(i>0){
flag = true;
}
}catch(SQLException e){
System.out.println("删除错误！");
e.printStackTrace();
}
return flag;
}
}
Newsdao.java
package com.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import bean.User;
public class Userdao {
private static final long serialVersionUID = 1L;
private String driverName="com.mysql.cj.jdbc.Driver";
private String url="jdbc:mysql://localhost:3306/newsdata?useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=true";
private String name="root";
private String pwd="123456";
public boolean login(User u) {
boolean flag=false;
String sql="select * from user where uname=‘"+u.getName()+"‘ and password=‘"+u.getPassword()+"‘";
System.out.println(sql);
Connection connection=null;
Statement statement=null;
ResultSet resultSet=null;
try {
//System.out.println("******************");
Class.forName(driverName);
try {
//System.out.println("##################3");
connection = DriverManager.getConnection(url, name, pwd);
//System.out.println("******************");
statement = connection.createStatement();
resultSet = statement.executeQuery(sql);
flag=resultSet.next();
resultSet.close();
statement.close();
connection.close();
//System.out.println(flag+"**********");
} catch (SQLException e) {
e.printStackTrace();
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return flag;
}
}
Userdao.java
package servlet;
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;
import com.dao.Newsdao;
import bean.News;
@WebServlet("/AddServlet")
public class AddServlet extends HttpServlet {
public AddServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=UTF-8");
String title=request.getParameter("title");
String type=request.getParameter("type");
String datetime=request.getParameter("datetime");
String content=request.getParameter("ueditor");
System.out.println("这是ueditor的内容"+title+content);
News news=new News();
news.setTitle(title);
news.setContent(content);
news.setDatetime(datetime);
news.setType(type);
Newsdao nd=new Newsdao();
try{
nd.addNews(news);
response.sendRedirect("newslistServlet");
//request.getRequestDispatcher("/newslist.jsp").forward(request, response);
}catch(Exception e) {
System.out.println("添加失败");
}
}
}
AddServlet.java
package servlet;
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;
import com.dao.Newsdao;
@WebServlet("/DeleteServlet")
public class DeleteServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public DeleteServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String id=(String)request.getParameter("id");
System.out.println("被删除的新闻");
int nid=Integer.parseInt(id);
Newsdao nd=new Newsdao();
nd.delete(nid);
response.sendRedirect("newslistServlet");
}
}
DeleteServlet.java
package servlet;
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;
import com.dao.Newsdao;
import bean.News;
@WebServlet("/UpdateServlet")
public class UpdateServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public UpdateServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
request.setCharacterEncoding("utf-8");
String id=request.getParameter("id");
System.out.println("id的值为"+id);
int nid=Integer.parseInt(id);
String title=request.getParameter("title");
String type=request.getParameter("type");
String datetime=request.getParameter("datetime");
String content=request.getParameter("editor");
News news=new News();
news.setId(nid);
news.setTitle(title);
news.setContent(content);
news.setDatetime(datetime);
news.setType(type);
Newsdao nd=new Newsdao();
try{
nd.update(news);
response.sendRedirect("newslistServlet");
}catch(Exception e) {
System.out.println("修改失败");
}
}
}
UpdataServlet.java
package servlet;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dao.Newsdao;
import bean.News;
@WebServlet("/SelectServlet")
public class SelectServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public SelectServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;cahrset=utf-8");
String id=request.getParameter("id");
int nid=Integer.parseInt(id);
Newsdao nd=new Newsdao();
List<News> list=nd.selectByID(nid);
request.setAttribute("news", list);
System.out.println(list.size());
request.getRequestDispatcher("/content.jsp").forward(request, response);
}
}
SelectServlet.java
标签：war .sql 修改 Servle 小型 url 作用 .exe slist
原文地址：https://www.cnblogs.com/wajp/p/10886934.html
