forked from admin/struts2-demo
173 lines
8.6 KiB
Plaintext
173 lines
8.6 KiB
Plaintext
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
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<!DOCTYPE html>
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<html lang="zh-CN">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<title>数据封装 - Struts2 学习</title>
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<style>
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body { font-family: 'Segoe UI', 'PingFang SC', sans-serif; background: linear-gradient(135deg, #667eea, #764ba2); min-height: 100vh; margin: 0; padding: 20px; }
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.container { max-width: 1200px; margin: 0 auto; }
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.breadcrumb { background: white; padding: 15px 25px; border-radius: 10px; margin-bottom: 20px; }
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.breadcrumb a { color: #667eea; text-decoration: none; }
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.content { background: white; border-radius: 20px; padding: 40px; box-shadow: 0 10px 40px rgba(0,0,0,0.2); }
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h1 { color: #667eea; border-bottom: 3px solid #667eea; padding-bottom: 15px; }
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h2 { color: #764ba2; margin-top: 30px; }
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.section { margin: 25px 0; padding: 20px; background: #f8f9fa; border-radius: 10px; }
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pre { background: #1e1e1e; color: #d4d4d4; padding: 20px; border-radius: 10px; overflow-x: auto; font-size: 0.9em; }
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.keyword { color: #569cd6; }
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.string { color: #ce9178; }
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.comment { color: #6a9955; }
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.btn { display: inline-block; padding: 12px 30px; background: #667eea; color: white; text-decoration: none; border-radius: 25px; margin-right: 10px; }
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.note { background: #fff3e0; border-left: 4px solid #ff9800; padding: 15px; margin: 20px 0; border-radius: 0 10px 10px 0; }
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</style>
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</head>
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<body>
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<div class="container">
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<div class="breadcrumb">
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<a href="/">🏠 首页</a> / 数据封装
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</div>
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<div class="content">
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<h1>📦 数据封装 - 属性驱动 vs 模型驱动</h1>
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<div class="note">
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<strong>📝 本节要点：</strong> 掌握 Struts2 两种数据封装方式，将请求参数封装到 Java 对象
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</div>
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<h2>1. 两种封装方式对比</h2>
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<div class="section">
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<table style="width:100%; border-collapse: collapse;">
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<tr style="background:#667eea; color:white;">
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<th style="padding:10px;">方式</th>
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<th style="padding:10px;">实现</th>
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<th style="padding:10px;">适用场景</th>
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</tr>
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<tr style="background:#f8f9fa;">
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<td style="padding:10px;"><strong>属性驱动</strong></td>
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<td style="padding:10px;">Action 中定义属性 + getter/setter</td>
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<td style="padding:10px;">简单场景，属性较少</td>
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</tr>
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<tr>
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<td style="padding:10px;"><strong>模型驱动</strong></td>
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<td style="padding:10px;">实现 ModelDriven 接口</td>
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<td style="padding:10px;">复杂对象，表单字段多</td>
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</tr>
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</table>
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</div>
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<h2>2. 方式一：属性驱动 (Property Driven)</h2>
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<h3>2.1 基本属性封装</h3>
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<div class="section">
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<pre><span class="comment">/**
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* 直接在 Action 中定义属性
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* 表单: <input name="username"> 会自动调用 setUsername()
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*/</span>
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<span class="keyword">public class</span> UserAction <span class="keyword">extends</span> ActionSupport {
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<span class="comment">// Struts2 自动调用 setter 注入参数</span>
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<span class="keyword">private</span> String username;
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<span class="keyword">private</span> String email;
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<span class="keyword">private</span> Integer age;
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<span class="annotation">@Override</span>
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<span class="keyword">public</span> String execute() {
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System.out.println(username + <span class="string">" - "</span> + email + <span class="string">" - "</span> + age);
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<span class="keyword">return</span> SUCCESS;
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}
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<span class="comment">// 必须提供 setter 和 getter</span>
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<span class="keyword">public</span> String getUsername() { <span class="keyword">return</span> username; }
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<span class="keyword">public void</span> setUsername(String username) { <span class="keyword">this</span>.username = username; }
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<span class="keyword">public</span> String getEmail() { <span class="keyword">return</span> email; }
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<span class="keyword">public void</span> setEmail(String email) { <span class="keyword">this</span>.email = email; }
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<span class="keyword">public</span> Integer getAge() { <span class="keyword">return</span> age; }
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<span class="keyword">public void</span> setAge(Integer age) { <span class="keyword">this</span>.age = age; }
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}</pre>
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</div>
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<h3>2.2 复杂属性 (嵌套对象)</h3>
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<div class="section">
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<p>表单中的 <code>user.username</code> 会自动调用 setUser(用户对象).setUsername()</p>
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<pre><span class="comment">// Action</span>
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<span class="keyword">private</span> User user; <span class="comment">// 包含 username, email 属性的对象</span>
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<span class="comment">// 表单</span>
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<span class="keyword"><input</span> name=<span class="string">"user.username"</span>/>
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<span class="keyword"><input</span> name=<span class="string">"user.email"</span>/></pre>
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</div>
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<h2>3. 方式二：模型驱动 (ModelDriven)</h2>
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<div class="note">
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<strong>💡 推荐：</strong> 对于复杂表单，使用模型驱动更清晰，Action 和 Model 分离
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</div>
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<div class="section">
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<pre><span class="keyword">import</span> com.opensymphony.xwork2.ModelDriven;
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<span class="comment">/**
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* 实现 ModelDriven 接口
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* 需要:
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* 1. 实现 getModel() 方法
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* 2. 泛型指定模型类型
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*/</span>
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<span class="keyword">public class</span> UserAction <span class="keyword">extends</span> ActionSupport <span class="keyword">implements</span> ModelDriven<User> {
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<span class="comment">// 模型对象</span>
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<span class="keyword">private</span> User user = <span class="keyword">new</span> User();
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<span class="comment">/**
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* 返回模型对象
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* Struts2 会把参数注入到返回的对象中
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*/</span>
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<span class="annotation">@Override</span>
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<span class="keyword">public</span> User getModel() {
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<span class="keyword">return</span> user;
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}
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<span class="annotation">@Override</span>
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<span class="keyword">public</span> String execute() {
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<span class="comment">// 直接使用 user 对象</span>
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System.out.println(user.getUsername());
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<span class="keyword">return</span> SUCCESS;
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}
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}</pre>
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</div>
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<h2>4. List/Map 属性封装</h2>
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<div class="section">
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<pre><span class="comment">// Action - 接收 List</span>
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<span class="keyword">private</span> List<User> users;
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<span class="keyword">public void</span> setUsers(List<User> users) { <span class="keyword">this</span>.users = users; }
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<span class="keyword">public</span> List<User> getUsers() { <span class="keyword">return</span> users; }
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<span class="comment">// 页面表单 - users[0].username, users[1].username</span>
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<span class="keyword"><input</span> name=<span class="string">"users[0].username"</span> value=<span class="string">"张三"</span>/>
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<span class="keyword"><input</span> name=<span class="string">"users[1].username"</span> value=<span class="string">"李四"</span>/>
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<span class="comment">// Action - 接收 Map</span>
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<span class="keyword">private</span> Map<String, User> userMap;
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<span class="keyword"><input</span> name=<span class="string">"userMap['one'].username"</span>/></pre>
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</div>
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<h2>5. 封装流程图</h2>
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<div class="section">
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<pre style="text-align: center; font-size: 1.1em;">
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请求参数 → Action setter 方法 → 属性赋值
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↓
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实现 ModelDriven → getModel() → 模型对象赋值
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↓
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值栈 (Value Stack)</pre>
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</div>
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<div style="margin-top: 30px;">
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<a href="/demo/upload" class="btn">下一节：文件上传 →</a>
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<a href="/" class="btn" style="background: #764ba2;">← 返回首页</a>
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</div>
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</div>
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</div>
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</body>
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</html> |