Question

mvc模式流程

本人学过JavaBean和servlet的基础，现在想了解mvc开发（jsp+JavaBean+servlet）的方法，请以用户登录主页后新闻的显示说明，谢谢，请给出源码

Answer 1

//Struts MVC 程序示例
package cn.siox.web.struts;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

public class LoginAction extends Action {

@Override
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
LoginActionForm lf=(LoginActionForm)form;
// return mapping.findForward("sucess");
// if(lf.getUsername().equals("admin")&&lf.getPassword().equals("admin")){
// //提交成功
// return mapping.findForward("success");
// }else {
// //提交失败
// return mapping.findForward("error");
// }
try{
ValidateManager vm=ValidateManager.class.newInstance();
vm.login(lf.getUsername(), lf.getPassword());
request.setAttribute("username", lf.getUsername());
return mapping.findForward("success");
}catch(UserNotFoundException ue){
//ue.printStackTrace();
System.out.println("------------------>用户找不到");
System.out.println(lf.getUsername());
request.setAttribute("errorinfo", "用户找不到："+lf.getUsername());
return mapping.findForward("error");
}catch(PasswordErrorException pe){
//pe.printStackTrace();
System.out.println("------------------>密码错了");
request.setAttribute("errorinfo", "娘的，密码错了：");
return mapping.findForward("error");
}
}

}

package cn.siox.web.struts;

import org.apache.struts.action.ActionForm;

/**
*
* @author Lindily
*
*/

/**
* 登陆的ActionForm，他专门来做数据的收集
*/

public class LoginActionForm extends ActionForm {
private String username,password;

public String getUsername() {
return username;
}

public void setUsername(String username) {
this.username = username;
}

public String getPassword() {
return password;
}

public void setPassword(String password) {
this.password = password;
}

}

package cn.siox.web.struts;

public class PasswordErrorException extends RuntimeException {

}

package cn.siox.web.struts;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.InputStreamReader;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

/**
* @author Lindily
*
*/
public class SupportAction extends Action {

@Override
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
request.setCharacterEncoding("utf-8");
SupportActionForm sf=(SupportActionForm)form;
System.out.println("-------->"+sf.getText());
request.setAttribute("support", "<h3>感谢！</h3><p>你提供的建议："+sf.getText()+" 我们已经保存");
return mapping.findForward("support");
}

}

package cn.siox.web.struts;

import org.apache.struts.action.ActionForm;

/**
* @author Lindily
*
*/
public class SupportActionForm extends ActionForm {
private String text;

public String getText() {
return text;
}

public void setText(String text) {
this.text = text;
}

}

package cn.siox.web.struts;

public class UserNotFoundException extends RuntimeException {

}

package cn.siox.web.struts;

public class ValidateManager {

public void login(String user,String pass){
if(!"root".equals(user)){
throw new UserNotFoundException();
}
if(!"123456".equals(pass)){
throw new PasswordErrorException();
}
}
}

//web.xml 配置

<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<load-on-startup>2</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.go</url-pattern>
</servlet-mapping>
</web-app>

//struts-config.xml

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts-config PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 1.3//EN"
"http://struts.apache.org/dtds/struts-config_1_3.dtd">

<struts-config>
<form-beans>
<form-bean name="loginform" type="cn.siox.web.struts.LoginActionForm" />
<form-bean name="supportform" type="cn.siox.web.struts.SupportActionForm" />
</form-beans>

<action-mappings>
<action path="/login" type="cn.siox.web.struts.LoginAction" name="loginform" scope="request">
<forward name="success" path="/success.jsp"></forward>
<forward name="error" path="/error.jsp"></forward>
</action>

<action path="/support" type="cn.siox.web.struts.SupportAction" name="supportform" scope="request">
<forward name="support" path="/support.jsp"></forward>
</action>
</action-mappings>
</struts-config>

Answer 2

M:model 实体层，主要是javabean，封装数据的，它负责数据操作。
v：view 视图层，jsp html的页面
c：control 控制器（逻辑层） jsp页面提交的数据交由它判断，并根据判断结果转向相应的数据操作，即调用具体的javabean类。

Answer 3

mvc模式对开发来讲很好用，建议采用struts等框架，虽然学习起来需要花上一段时间，但是学会之后很好用的，不妨试一下

Answer 4

我有登录的页面，你可以直接拿去链接到你的新闻显示页，如果要的话百度hi我，我的邮箱是zhanghongzhen0301@163.com

Answer 5

MVC = model(模型)+view(视图)+control(控制器)