javaweb下MVC模式即学即用
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时间：2015年06月08日
<img src="http://img.blog.csdn.net/20150327153134076?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvZ3JlZW5saWdodF83NDExMA==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" alt="" />
1.搭建开发环境
1.1 导入项目所需的开发包
dom4j-1.6.1.jar
jaxen-1.1-beta-6.jar
commons-beanutils-1.8.0.jar
commons-logging.jar
jstl.jar
standard.jar
1.2 创建程序的包名
cn.itcast.domain
cn.itcast.dao
cn.itcast.dao.impl
cn.itcast.service
cn.itcast.service.impl
cn.itcast.web.controller
cn.itcast.web.UI (user interface)(放为用户提供用户界面的servlet)
cn.itcast.utils
junit.test
在web-inf\jsp目录，保存jsp页面
1.3 在类目录下面，创建用于保存用户数据的xml文件(users.xml)
2、开发实体user
private String id;
private String username;
private String password;
private String email;
private Date birthday;
3、开发dao(Data Access Object)
3.1 开发UserDaoXmlImpl
public void add(User user)
public User find(String username)
public User find(String username,String password)
3.2 抽取接口：UserDao
3.3 开发工具类： XmlUtils
3.4 开发测试类：Junit
4、开发service(service 对web层提供所有的业务服务)
4.1 开发BusinessServiceImp
public void registerUser(User user) throws UserExistException
public User loginUser(String username,String password);
3.2 抽取接口：BusinessService
3.3 开发工具类： WebUtils
3.4 开发测试类：Junit
5、开发web层
5.1 开发注册
5.1.1 写一个RegisterUIServlet为用户提供注册界面,它收到请求，跳到register.jsp
5.1.2 写register.jsp
5.1.3 register.jsp提交请求，交给RegisterServlet处理
5.1.4 写RegisterServlet
1.设计用于校验表单数据RegisterFormbean
2、写WebUtils工具类，封装请求数据到formbean中
3、如果校验失败跳回到register.jsp，并回显错误信息
4、如果校验通过，调用service向数据库中注册用户
5.2 开发登陆
5.2.1 写一个LoginUIServlet为用户提供注册界面,它收到请求，跳到login.jsp
5.2.2 login.jsp提交给LoginServlet处理登陆请求
6.3 开发注销
6.2.1 写一个LogoutUIServlet为用户提供注册界面,它收到请求，跳到logout.jsp
6.2.2 logout.jsp提交给LogoutServlet处理登陆请求
<img src="http://img.blog.csdn.net/20150327153218677?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvZ3JlZW5saWdodF83NDExMA==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" alt="" />
package he.junhua.domain;
import java.util.Date;
//实体类User
public class User {
private String id;
private String username;
private String password;
private Date birthday;
private String email;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
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;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
//UserDao接口的实现
package he.junhua.dao.impl;
import java.text.SimpleDateFormat;
import org.dom4j.Document;
import org.dom4j.Element;
import he.junhua.dao.UserDao;
import he.junhua.domain.User;
import he.junhua.utils.XmlUtils;
public class UserDaoXmlImpl implements UserDao {
public void add(User user){
try {
Document document = XmlUtils.getDocument();
Element root = document.getRootElement();
Element user_tag = root.addElement("user");
user_tag.setAttributeValue("id", user.getId());
user_tag.setAttributeValue("username", user.getUsername());
user_tag.setAttributeValue("password", user.getPassword());
user_tag.setAttributeValue("email", user.getEmail());
user_tag.setAttributeValue("birthday", user.getBirthday()==null?"":user.getBirthday().toLocaleString());
XmlUtils.write2Xml(document);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public User find(String username,String password){
try {
Document document = XmlUtils.getDocument();
Element e = (Element) document.selectSingleNode("//user[@username='"+username+"' and @password='"+password+"']");
//判断用户名和密码是否合法
if(e==null){
return null;
}
//new出一个user用以存放查找所得信息
User user = new User();
String date = e.attributeValue("birthday");
if(date==null||date.equals("")){
user.setBirthday(null);
}else{
//将String转换成Date
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
user.setBirthday(format.parse(date));
}
user.setUsername(e.attributeValue("username"));
user.setPassword(e.attributeValue("password"));
user.setId(e.attributeValue("id"));
user.setEmail(e.attributeValue("email"));
return user;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public boolean find(String username){
try {
Document document = XmlUtils.getDocument();
Element e = (Element) document.selectSingleNode("//user[@username='"+username+"']");//XPath
//判断用户名是否存在
if(e==null){
return false;
}
return true;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
//抽取接口，以便以后对程序修改时就可以根据需要直接实现该接口（即重写以上的UserDaoImpl）
package he.junhua.dao;
import he.junhua.domain.User;
public interface UserDao {
void add(User user);
User find(String username, String password);
//查找请求的用户是否存在
boolean find(String username);
}
//开发工具类XmlUtils，在这里引入了dom4j工具包
package he.junhua.utils;
import java.io.FileOutputStream;
import java.io.IOException;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
public class XmlUtils {
private static String filepath;
static {
filepath = XmlUtils.class.getClassLoader().getResource("users.xml")
.getPath();
}
public static Document getDocument() throws DocumentException {
SAXReader reader = new SAXReader();
Document document = reader.read(filepath);
return document;
}
public static void write2Xml(Document document) throws IOException{
// Pretty print the document to System.out
OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("utf-8");
XMLWriter writer = new XMLWriter(new FileOutputStream(filepath), format );
writer.write( document );
writer.close();
}
}
//对上述代码的功能作一简单测试，如有错及时debug，否则继续前进
package junit.test;
import java.util.Date;
import he.junhua.dao.impl.UserDaoXmlImpl;
import he.junhua.domain.User;
import org.junit.Test;
public class UserDaoTest {
@Test
public void testAdd() throws Exception {
User user = new User();
user.setUsername("bbb");
user.setPassword("123");
user.setEmail("[email protected]");
user.setBirthday(new Date());
user.setId("222");
new UserDaoXmlImpl().add(user);
}
@Test
public void testFind1(){
boolean b = new UserDaoXmlImpl().find("ccc");
System.out.println(b);
}
@Test
public void testFind2(){
User user = new User();
user = new UserDaoXmlImpl().find("ccc","vL4zZeasleosA0OiOVg03Q==");
System.out.println(user);
}
}
//开发service,对WEB层提供所有的业务服务
package he.junhua.service.impl;
import he.junhua.dao.UserDao;
import he.junhua.dao.impl.UserDaoXmlImpl;
import he.junhua.domain.User;
import he.junhua.exception.UserExistException;
import he.junhua.service.BusinessService;
import he.junhua.utils.WebUtils;
public class BusinessServiceImpl implements BusinessService {
UserDao dao = new UserDaoXmlImpl(); //实际中常使用工厂模式 spring
//对WEB层提供注册服务
public void register(User user) throws UserExistException{
if(dao.find(user.getUsername())){
throw new UserExistException("用户已存在！！");
//发现用户已存在，则给web层抛出一个异常，提醒web层处理该异常，并且给用户友好提示
}else{
user.setPassword(WebUtils.md5(user.getPassword()));
dao.add(user);
}
}
//对WEB层提供登录服务
public User login(String username,String password){
password = WebUtils.md5(password);
return dao.find(username, password);
}
}
//同理，要抽取service接口
package he.junhua.service;
import he.junhua.domain.User;
import he.junhua.exception.UserExistException;
public interface BusinessService {
//对WEB层提供注册服务
void register(User user) throws UserExistException;
//对WEB层提供登录服务
User login(String username, String password);
}
//对service层作一简单测试
package junit.test;
import he.junhua.domain.User;
import he.junhua.exception.UserExistException;
import he.junhua.service.BusinessService;
import he.junhua.service.impl.BusinessServiceImpl;
import java.util.Date;
import org.junit.Test;
public class ServiceTest {
@Test
public void testRigister(){
User user = new User();
user.setUsername("aaa");
user.setPassword("111");
user.setEmail("[email protected]");
user.setBirthday(new Date());
user.setId("111");
BusinessService bs = new BusinessServiceImpl();
try {
bs.register(user);
System.out.println("用户注册成功！");
} catch (UserExistException e) {
System.out.println("用户已经存在！");
}
}
@Test
public void testLogin(){
BusinessService bs = new BusinessServiceImpl();
User user = bs.login("bbb", "123");
System.out.println(user);
}
}
//开发web层
//开发注册模块
//RegisterUIServlet为用户提供注册界面
package he.junhua.web.UI;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class RegisterUIServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.getRequestDispatcher("/WEB-INF/jsp/register.jsp").forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
//注册页面，由RegisterUIServlet跳转过来
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>用户注册</title>
</head>
<body style="text-align: center;">
<form action="${pageContext.request.contextPath }/servlet/RegisterServlet" method="post">
<div align="center" style="color:blue;background-color: fuchsia; " >
<table width="641" border="1" height="228">
<tr>
<td>用户名</td>
<td>
<input type="text" name="username" value="${formbean.username }">${formbean.errors.username }
</td>
</tr>
<tr>
<td>密码</td>
<td>
<input type="password" name="password" value="${formbean.password }">${formbean.errors.password }
</td>
</tr>
<tr>
<td>确认密码</td>
<td>
<input type="password" name="password2" value="${formbean.password2 }">${formbean.errors.password2 }
</td>
</tr>
<tr>
<td>邮箱</td>
<td>
<input type="text" name="email" value="${formbean.email }">${formbean.errors.email }
</td>
</tr>
<tr>
<td>生日</td>
<td>
<input type="text" name="birthday" value="${formbean.birthday }">${formbean.errors.birthday }
</td>
</tr>
<tr>
<td>
<input type="reset" value="清空">
</td>
<td>
<input type="submit" value="注册">
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
//register.jsp提交请求，交给RegisterServlet处理
package he.junhua.web.controller;
import he.junhua.domain.User;
import he.junhua.exception.UserExistException;
import he.junhua.service.BusinessService;
import he.junhua.service.impl.BusinessServiceImpl;
import he.junhua.utils.WebUtils;
import he.junhua.web.formbean.RegisterFormBean;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class RegisterServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//将表单数据封装到formbean中（功能模块化）
RegisterFormBean formbean = WebUtils.request2Bean(request, RegisterFormBean.class);
//表单校检
//如果不合法，则重新跳回注册界面并对提交失败的信息回显
if(!formbean.isValidate()){
formbean.setPassword(null);
formbean.setPassword2(null);
request.setAttribute("formbean", formbean);
request.getRequestDispatcher("/WEB-INF/jsp/register.jsp").forward(request, response);
return;
}
//如果校检通过，则调用service处理请求
User user = new User();
WebUtils.copyBean(formbean, user);
user.setId(WebUtils.generateID());
BusinessService service = new BusinessServiceImpl();
try {
service.register(user);
request.setAttribute("message", "用户注册成功!!");
request.getRequestDispatcher("/message.jsp").forward(request, response);
} catch (UserExistException e) {
formbean.getErrors().put("username", "用户已存在!");
request.setAttribute("formbean", formbean);
request.getRequestDispatcher("/WEB-INF/jsp/register.jsp").forward(request, response);
} catch (Exception e) {
request.setAttribute("message", "注册失败！（服务器未知错误）");
request.getRequestDispatcher("/message.jsp").forward(request, response);
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
//设计RegisterFormBean类，并提供合法性校检方法isValidate()
package he.junhua.web.formbean;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.beanutils.locale.converters.DateLocaleConverter;
public class RegisterFormBean {
private String username;
private String password;
private String password2;
private String email;
private String birthday;
private Map<String, String> errors = new HashMap();
public Map<String, String> getErrors() {
return errors;
}
public void setErrors(Map<String, String> errors) {
this.errors = errors;
}
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;
}
public String getPassword2() {
return password2;
}
public void setPassword2(String password2) {
this.password2 = password2;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getBirthday() {
return birthday;
}
public void setBirthday(String birthday) {
this.birthday = birthday;
}
/*
private String username; 用户名不能为空，并且要是3-8的字符 abcdABcd
private String password; 密码不能为空，并且要是3-8的数字
private String password2; 两次密码要一致
private String email; 可以为空，不为空要是一个合法的邮箱
private String birthday; 可以为空，不为空时，要是一个合法的日期
正则表达式可以通过在javaAPI中搜索pattern得到
*
*/
public boolean isValidate(){
boolean isOk = true;
if(this.username==null||this.username.trim().equals("")){
isOk = false;
errors.put("username", "用户名不能为空！");
}else{
if(!this.username.matches("[a-zA-Z]{3,8}")){
isOk = false;
errors.put("username", "用户名必须是3-8位的字母！");
}
}
if(this.password==null||this.password.trim().equals("")){
isOk = false;
errors.put("password", "密码不能为空！");
}else{
if(!this.password.matches("\\d{3,8}")){
isOk = false;
errors.put("password", "密码必须是3-8位的数字！");
}
}
if(this.password2!=null){
if(!this.password2.equals(this.password)){
isOk = false;
errors.put("password2", "两次密码必须一致！");
}
}
if(this.email!=null){
if(!this.email.matches("\\w+@\\w+(\\.\\w+)+")){
isOk = false;
errors.put("email", "不是一个合法的邮箱！");
}
}
if(this.birthday!=null){
try {
//检验生日格式是否合法常用的方法
DateLocaleConverter converter = new DateLocaleConverter();
converter.convert(this.birthday);
} catch (Exception e) {
isOk = false;
errors.put("birthday", "不是合法的生日！");
}
}
return isOk;
}
}
//设计工具类WebUtil
package he.junhua.utils;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Date;
import java.util.Enumeration;
import java.util.UUID;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.beanutils.ConvertUtils;
import org.apache.commons.beanutils.locale.converters.DateLocaleConverter;
import sun.misc.BASE64Encoder;
public class WebUtils {
//对password加密
public static String md5(String data){
try {
MessageDigest md = MessageDigest.getInstance("md5");
byte[] md5 = md.digest(data.getBytes());
return new BASE64Encoder().encode(md5);
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e);
}
}
//将request携带来的参数写入formbean
public static <T>T request2Bean(HttpServletRequest request,Class<T> clazz){
try {
T bean = clazz.newInstance();
Enumeration e = request.getParameterNames();
while(e.hasMoreElements()){
String name = (String) e.nextElement();
String value = request.getParameter(name);
BeanUtils.setProperty(bean, name, value);
}
return bean;
} catch (Exception e) {
throw new RuntimeException();
}
}
//用于两个bean对象间的bean复制
public static void copyBean(Object src,Object dest){
ConvertUtils.register(new DateLocaleConverter(), Date.class);
try {
BeanUtils.copyProperties(dest, src);
} catch (Exception e) {
throw new RuntimeException();
}
}
//为user产生唯一的ID
public static String generateID(){
return UUID.randomUUID().toString();
}
}
//同理，开发登录模块
package he.junhua.web.UI;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginUIServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
//登录页面
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>用户登录</title>
</head>
<body>
<div align="center" style="background-color: yellow;">
<form action="${pageContext.request.contextPath }/servlet/LoginServlet" method="post">
用户名：<input name="username" type="text"/><br/>
密码： <input name="password" type="password"/><br/>
<input value="登录" type="submit">
</form>
</div>
</body>
</html>
//交给LoginServlet处理
package he.junhua.web.controller;
import he.junhua.domain.User;
import he.junhua.service.BusinessService;
import he.junhua.service.impl.BusinessServiceImpl;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
BusinessService service = new BusinessServiceImpl();
User user = service.login(username, password);
if(user==null){
request.setAttribute("message", "用户名或密码错误!");
request.getRequestDispatcher("/message.jsp").forward(request, response);
return;
}
request.getSession().setAttribute("user", user);
request.setAttribute("message", "欢迎您，"+user.getUsername()+"!<br/>3秒后将自动跳转到首页...<meta http-equiv='refresh' content='3;url=/day7/index.jsp'>");
request.getRequestDispatcher("/message.jsp").forward(request, response);
//response.sendRedirect("/message.jsp");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
//注销模块
package he.junhua.web.controller;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class LogoutServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
HttpSession session = request.getSession(false);
if(session!=null){
//注销实际上就是将存在session域中的user清除掉
session.removeAttribute("user");
}
request.setAttribute("message", "用户注销成功，5秒钟后将自动跳转到首页！<meta http-equiv='refresh' content='5;url="+request.getContextPath()+"/index.jsp'>");
request.getRequestDispatcher("/message.jsp").forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
//最后对细节方面进行优化
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