学习笔记 : Java web之JSP 开发模型
JSP Model1
简介 : JSP Model1采用JSP+JavaBean的技术,将页面显示和业务逻辑分开.其中,JSP实现流程控制和页面显示,JavaBean对象封装数据和业务逻辑.这种设计实现了数据,业务逻辑和页面显示的分离,在一定程度上实现了程序开发的模块化,降低了程序修改和维护的难度.
JSP Model1 案例
案例描述 : 通过一个简单的网络计算器程序来深化对JSP Model1模型的理解.
Calculator.java : 封装计算器中的数据,处理业务逻辑.
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111package pers.huangyuhui.jspmodel.model1.calculator;
import java.math.BigDecimal;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Pattern;
/**
* @ClassName: Calculator
* @Description: 封装计算器中的数据及处理业务逻辑
* @author: HuangYuhui
* @date: May 5, 2019 10:10:43 AM
*
*/
public class Calculator {
private char operator;
private String firstNumber;
private String secondNumber;
private Map<String, String> errors = new HashMap<String, String>();// 封装错误信息
public String getFirstNumber() {
return firstNumber;
}
public void setFirstNumber(String firstNumber) {
this.firstNumber = firstNumber;
}
public String getSecondNumber() {
return secondNumber;
}
public void setSecondNumber(String secondNumber) {
this.secondNumber = secondNumber;
}
public char getOperator() {
return operator;
}
public void setOperator(char operator) {
this.operator = operator;
}
public Map<String, String> getErrors() {
return errors;
}
public void setErrors(Map<String, String> errors) {
this.errors = errors;
}
// 运算操作
public String caculate() {
BigDecimal result = null;
BigDecimal firstNum = new BigDecimal(firstNumber);
BigDecimal secondNum = new BigDecimal(secondNumber);
switch (operator) {
case '+':
result = firstNum.add(secondNum);
break;
case '-':
result = firstNum.subtract(secondNum);
break;
case '*':
result = firstNum.multiply(secondNum);
break;
case '/':
if ("0".equals(secondNumber)) {
// throw new RuntimeException("除数不能为 0 !");
return null;
}
result = firstNum.divide(secondNum);
break;
default:
break;
}
return result.toString();
}
// 验证表单传入的数据是否合法
public boolean validate() {
boolean flag = true;
Pattern pattern = Pattern.compile("\\d+");// 匹配数字
if (firstNumber == null || "".equals(firstNumber)) {
errors.put("firstNumberErrorInfo", "第一个运算数不能为空 !");
flag = false;
} else if (!pattern.matcher(firstNumber).matches()) {
errors.put("firstNumberErrorInfo", "第一个运算数必须为数字 !");
flag = false;
}
if (secondNumber == null || "".equals(secondNumber)) {
errors.put("secondNumberErrorInfo", "第二个运算数不能为空 !");
flag = false;
} else if (!pattern.matcher(secondNumber).matches()) {
errors.put("secondNumberErrorInfo", "第二个运算数必须为数字 !");
flag = false;
} else if ("0".equals(secondNumber)) {
errors.put("secondNumberErrorInfo", "被除数不能为 0 !");
flag = false;
}
return flag;
}
}calculator.jsp : 显示网络计算机的页面.
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93<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" import="java.util.Map"%>
<jsp:useBean id="calculator" class="pers.huangyuhui.jspmodel.model1.calculator.Calculator"/>
<jsp:setProperty property="*" name="calculator"/>
<html>
<head>
<meta charset="UTF-8">
<title>JSP Model 1</title>
<style>
span{
font-size:13px;
color:red;
}
#main{
width:600px;
margin-left: 425px;
}
#main tr{
height:40px;
}
#main tr td{
width: 50px;
}
#main tr td input{
width: 200px;
}
.buttom {
text-align: center;
padding-top: 25px;
}
.buttom .calculate{
margin-right: 65px;
}
</style>
</head>
<body>
<h3 align="center">JSP Mode 1 : 计算器</h3><hr/>
<form action="" method="post">
<table id="main">
<tr>
<td> 第一个运算数</td>
<td >
<input type="text" name="firstNumber"/>
<span>${errors.firstNumberErrorInfo }</span>
</td>
</tr>
<tr>
<td> 运算符</td>
<td>
<select name="operator" style="margin-left:65px">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
</td>
</tr>
<tr>
<td>第二个运算符</td>
<td>
<input type="text" name="secondNumber"/>
<span>${errors.secondNumberErrorInfo }</span>
</td>
</tr>
<tr>
<td>运算结果: </td>
<td>
<%
Map<String,String> errorInfo = calculator.getErrors();
if(calculator.validate()){
pageContext.getSession().removeAttribute("errors");
%>
<font color="green">
<jsp:getProperty property="firstNumber" name="calculator"/>
<jsp:getProperty property="operator" name="calculator"/>
<jsp:getProperty property="secondNumber" name="calculator"/>
= <%=calculator.caculate() %>
<%
}else{
pageContext.getSession().setAttribute("errors",errorInfo);
}
%>
</font>
</td>
</tr>
</table>
<div class="buttom">
<input class="calculate" type="submit" value="计算"/>
<input type="reset" value="重置"/>
</div>
</form>
</body>
</html>程序运行效果示例图.
JSP Model2
简介 : JSP Model2架构模型采用JSP+Servlet+JavaBean技术,其将JSP Model1中JSP页面里的流程控制代码提取出来.封装到Servlet中,从而实现了整个程序页面显示,流程控制和业务逻辑的分离.实际上JSP Model2就是MVC设计模式,其中控制器(Colltroller)的角色由Servlet实现,视图(View)的角色由JSP实现,模型(Model)的角色由JavaBean实现.
JSP Model2 案例
案例描述 : 按照JSP Model2的模型思想编写一个用户注册的简单示例程序.
UserBean.java : 封装用户的注册信息.
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47package pers.huangyuhui.jspmodel.model2.register;
/**
* @ClassName: UserBean
* @Description: 封装用户注册信息
* @author: HuangYuhui
* @date: May 5, 2019 4:35:21 PM
*
*/
public class UserBean {
private String name;
private String password;
private String email;
public UserBean(String name, String password, String email) {
super();
this.name = name;
this.password = password;
this.email = email;
}
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 String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}RegisterFormBean.java : 封装并效验注册表单信息的JavaBean.
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108package pers.huangyuhui.jspmodel.model2.register;
import java.util.HashMap;
import java.util.Map;
/**
* @ClassName: RegisterFormBean
* @Description: 效验注册表单信息
* @author: HuangYuhui
* @date: May 5, 2019 4:37:33 PM
*
*/
public class RegisterFormBean {
private String name;
private String password;
private String password2;
private String email;
// 存储验证表单时发生的错误信息
private Map<String, String> errors = new HashMap<String, String>();
public RegisterFormBean(String name, String password, String password2, String email) {
super();
this.name = name;
this.password = password;
this.password2 = password2;
this.email = email;
}
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 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;
}
// 获取注册信息效验时发生的错误信息
public Map<String, String> getErrors() {
return errors;
}
// 添加注册信息效验时发生的错误信息
public void setErrorsMsg(String error, String errorMsg) {
if ((error) != null && (errorMsg != null)) {
errors.put(error, errorMsg);
}
}
// 校验用户注册信息
public boolean validate() {
boolean flag = true;
if (name == null || name.trim().equals("")) {
errors.put("nameErrorInfo", "请输入用户名 !");
flag = false;
}
if (password == null || password.trim().equals("")) {
errors.put("passwordErrorInfo", "请输入密码 !");
flag = false;
} else if (password.length() > 16 || password.length() < 6) {
errors.put("passwordErrorInfo", "请输入6-12位的密码 !");
flag = false;
}
if (password != null && !password.equals(password2)) {
errors.put("password2ErrorInfo", "两次输入的密码不相同 !");
flag = false;
}
if (email == null || email.trim().equals("")) {
errors.put("emailErrorInfo", "请输入邮箱地址 !");
flag = false;
} else if (!email.matches("[a-zA-Z0-9_-]+@[a-zA-Z0-9_-]+(\\.[a-zA-Z0-9_-]+)+")) {
errors.put("emailErrorInfo", "邮箱地址格式错误 !");
flag = false;
}
return flag;
}
}DBUtil.java : 访问数据库的辅助类,充当DAO.
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48package pers.huangyuhui.jspmodel.model2.register;
import java.util.HashMap;
/**
* @ClassName: DBUtil
* @Description: 模拟数据库,充当DAO
* @author: HuangYuhui
* @date: May 5, 2019 4:50:10 PM
*
*/
public class DBUtil {
private static DBUtil instance = new DBUtil();
private HashMap<String, UserBean> users = new HashMap<String, UserBean>();
private DBUtil() {
// 向数据库中添加一条用户数据
UserBean firstUser = new UserBean("YUbuntu0109", "myPassword", "Gentleman_0109@outlook.com");
users.put("YUbuntu0109", firstUser);
}
public static DBUtil getInstance() {
return instance;
}
// 获取数据库中指定用户名的数据
public UserBean getUser(String userName) {
UserBean user = users.get(userName);
return user;
}
// 向数据库中添加新的用户数据
public boolean insertUser(UserBean user) {
if (user == null) {
return false;
}
String userName = user.getName();
if (users.get(userName) != null) {
return false;
}
users.put(userName, user);
return true;
}
}ControllerServlet.java : 控制器,负责处理用户注册的请求.
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65package pers.huangyuhui.jspmodel.model2.register;
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;
/**
* @ClassName: ColltrollerServlet
* @Description: 处理用户注册请求
* @author: HuangYuhui
* @date: May 5, 2019 5:01:46 PM
*
*/
public class ControllerServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public ControllerServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String name = request.getParameter("userName");
String password = request.getParameter("userPassword");
String password2 = request.getParameter("userPassword2");
String email = request.getParameter("userEmail");
// 效验用户提交的注册表单信息
RegisterFormBean registerFormBean = new RegisterFormBean(name, password, password2, email);
if (!registerFormBean.validate()) {
request.setAttribute("registerFromBean", registerFormBean);
request.getRequestDispatcher("/register.jsp").forward(request, response);
return;
}
// 存储用户注册信息
UserBean userBean = new UserBean(name, password2, email);
if (!DBUtil.getInstance().insertUser(userBean)) {
request.setAttribute("BDUtilErrorInfo", "抱歉! 你注册的用户名已存在啦 !");
request.setAttribute("registerFromBean", registerFormBean);
request.getRequestDispatcher("/register.jsp").forward(request, response);
return;
}
request.getSession().setAttribute("userBean", userBean);
response.getWriter().print("注册成功啦 ! 三秒后将自动跳转到用户注册信息的页面 !");
response.setHeader("refresh", "3;url=registerInfo.jsp");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}register.jsp : 用户注册页面.
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86<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<html>
<head>
<meta charset="UTF-8">
<title>JSP Model 2</title>
<style type="text/css">
h3{
text-align:center;
}
#main{
width:600px;
margin-left: 450px;
}
#main tr{
height:40px;
}
#main tr td{
width: 50px;
}
#main tr td input{
width: 200px;
}
span{
font-size:13px;
color:red;
}
.buttom {
text-align: center;
padding-top: 25px;
}
.buttom .register{
margin-right: 70px;
}
</style>
</head>
<body>
<h3>用户注册页面</h3>
<hr/>
<form action="ControllerServlet" method="post">
<table id="main">
<tr>
<td>用户名</td>
<td>
<input type="text" name="userName" value="${registerFromBean.name }"/>
<span>
${registerFromBean.errors.nameErrorInfo }
${BDUtilErrorInfo }
</span>
</td>
</tr>
<tr>
<td>密码</td>
<td>
<input type="password" name="userPassword" />
<span>
${registerFromBean.errors.passwordErrorInfo }
</span>
</td>
</tr>
<tr>
<td>确认密码</td>
<td>
<input type="password" name="userPassword2"/>
<span>
${registerFromBean.errors.password2ErrorInfo }
</span>
</td>
</tr>
<tr>
<td>邮箱</td>
<td>
<input type="text" name="userEmail" value="${registerFromBean.email }"/>
<span>
${registerFromBean.errors.emailErrorInfo }
</span>
</td>
</tr>
</table>
<div class="buttom">
<input class="register" type="submit" value="注册"/>
<input type="reset" value="重置"/>
</div>
</form>
</body>
</html>registerInfo.jsp : 用户注册成功页面.
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24<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<meta charset="UTF-8">
<title>JSP Model 2</title>
</head>
<body>
<h3 align="center">JSP Mode2 : 用户注册信息</h3>
<hr/>
<c:choose>
<c:when test="${sessionScope.userBean == null }">
<a href="${pageContext.request.contextPath }/register.jsp">你还未注册! 请注册哟ヾ(●´∀｀●) ~</a>
</c:when>
<c:otherwise>
<div align="center">
<p>你的姓名: ${sessionScope.userBean.name }</p>
<p>你的邮箱: ${sessionScope.userBean.email }</p>
</div>
</c:otherwise>
</c:choose>
</body>
</html>程序运行效果示例图.
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