222 lines
9.7 KiB
HTML
222 lines
9.7 KiB
HTML
<!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>AOP 切面编程 - Spring Boot</title>
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<style>
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* { margin: 0; padding: 0; box-sizing: border-box; }
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body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; max-width: 900px; margin: 0 auto; padding: 20px; background: #f5f5f5; }
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h1 { color: #6DB33F; margin: 20px 0; }
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h2 { color: #333; border-bottom: 2px solid #6DB33F; padding-bottom: 10px; margin: 20px 0 15px; }
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h3 { color: #6DB33F; margin: 15px 0 10px; }
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.card { background: white; padding: 25px; margin: 15px 0; border-radius: 8px; box-shadow: 0 2px 4px rgba(0,0,0,0.1); }
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.btn { display: inline-block; padding: 12px 24px; border-radius: 8px; text-decoration: none; font-weight: 500; cursor: pointer; border: none; }
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.btn-primary { background: #6DB33F; color: white; }
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.btn-primary:hover { background: #5da32f; }
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.btn-info { background: #17a2b8; color: white; }
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code { background: #f0f0f0; padding: 2px 8px; border-radius: 4px; font-family: 'Fira Code', monospace; }
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pre { background: #2d2d2d; color: #f8f8f2; padding: 20px; border-radius: 8px; overflow-x: auto; margin: 15px 0; }
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pre code { background: none; color: inherit; }
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table { width: 100%; border-collapse: collapse; margin: 15px 0; }
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th, td { border: 1px solid #ddd; padding: 12px; text-align: left; }
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th { background: #6DB33F; color: white; }
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tr:nth-child(even) { background: #f9f9f9; }
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.tip { background: #e7f3ff; padding: 15px; border-radius: 8px; margin: 15px 0; border-left: 4px solid #6DB33F; }
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.warn { background: #fff3cd; padding: 15px; border-radius: 8px; margin: 15px 0; border-left: 4px solid #ffc107; }
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.result-box { background: #2d2d2d; color: #f8f8f2; padding: 15px; border-radius: 8px; font-family: monospace; white-space: pre-wrap; margin-top: 10px; }
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.nav { margin-bottom: 20px; }
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.nav a { margin-right: 15px; color: #6DB33F; text-decoration: none; }
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.nav a:hover { text-decoration: underline; }
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.lab { background:#fff7e6; border-left:4px solid #fa8c16; padding:15px; border-radius:8px; margin:15px 0; }
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.lab h4 { color:#ad6800; margin-bottom:8px; }
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</style>
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</head>
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<body>
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<div class="nav">
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<a href="/">← 返回首页</a>
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<a href="/users.html">用户管理</a>
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<a href="/events.html">事件机制</a>
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</div>
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<h1>🔪 AOP 切面编程</h1>
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<div class="lab">
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<h4>🧪 实验任务卡（AOP）</h4>
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<label style="display:block;margin-bottom:8px;"><input id="aopTaskDone" type="checkbox" onchange="toggleAopTaskDone(this)"> 本任务我已经完成</label>
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<ul style="padding-left:20px;line-height:1.8;">
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<li>目标：观察同一请求如何触发 Before/After/Around 通知</li>
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<li>步骤1：调用用户接口 <code>/api/users</code></li>
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<li>步骤2：回到本页点击“刷新统计数据”</li>
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<li>预期：统计里能看到 Controller/Service 方法耗时累积</li>
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<li>常见坑：只看页面不看控制台，容易错过切面日志</li>
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</ul>
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</div>
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<div class="card">
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<h3>📊 实时性能统计</h3>
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<p>AOP 自动统计所有 Controller 和 Service 方法的执行时间</p>
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<button class="btn btn-primary" onclick="loadStats()">刷新统计数据</button>
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<button class="btn btn-info" onclick="demoValidationError()">演示校验失败</button>
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<div class="result-box" id="statsResult">点击按钮查看...</div>
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</div>
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<h2>📚 AOP 核心概念</h2>
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<div class="card">
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<h3>1. 什么是 AOP？</h3>
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<p>AOP (Aspect-Oriented Programming) 面向切面编程，是将<strong>横切关注点</strong>与<strong>业务逻辑</strong>分离的编程范式。</p>
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<div class="tip">
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<strong>横切关注点：</strong>日志、事务、安全、性能监控等，散布在多个模块中的公共功能。
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</div>
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</div>
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<div class="card">
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<h3>2. 核心术语</h3>
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<table>
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<tr><th>术语</th><th>说明</th></tr>
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<tr><td><strong>Aspect (切面)</strong></td><td>横切关注点的模块化封装</td></tr>
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<tr><td><strong>JoinPoint (连接点)</strong></td><td>程序执行的某个点（方法调用、异常抛出等）</td></tr>
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<tr><td><strong>Pointcut (切入点)</strong></td><td>匹配连接点的表达式</td></tr>
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<tr><td><strong>Advice (通知)</strong></td><td>在连接点执行的动作</td></tr>
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<tr><td><strong>Weaving (织入)</strong></td><td>将切面应用到目标对象的过程</td></tr>
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</table>
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</div>
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<div class="card">
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<h3>3. 五种通知类型</h3>
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<table>
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<tr><th>注解</th><th>执行时机</th><th>用途</th></tr>
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<tr><td><code>@Before</code></td><td>方法执行前</td><td>参数校验、权限检查</td></tr>
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<tr><td><code>@After</code></td><td>方法执行后（无论成功或异常）</td><td>资源清理</td></tr>
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<tr><td><code>@AfterReturning</code></td><td>方法成功返回后</td><td>结果处理、日志记录</td></tr>
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<tr><td><code>@AfterThrowing</code></td><td>方法抛出异常后</td><td>异常处理、错误日志</td></tr>
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<tr><td><code>@Around</code></td><td>环绕方法执行（最强大）</td><td>性能统计、事务管理</td></tr>
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</table>
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</div>
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<h2>💻 代码示例</h2>
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<div class="card">
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<h3>日志切面示例</h3>
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<pre><code>@Aspect
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@Component
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public class LoggingAspect {
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// 切入点：匹配所有 Controller 方法
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@Pointcut("execution(* com.example.demo.controller.*.*(..))")
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public void controllerMethods() {}
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// 前置通知
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@Before("controllerMethods()")
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public void logBefore(JoinPoint jp) {
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System.out.println("[AOP-Before] 方法开始: " + jp.getSignature().getName());
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}
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// 返回通知
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@AfterReturning(pointcut = "controllerMethods()", returning = "result")
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public void logAfterReturning(JoinPoint jp, Object result) {
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System.out.println("[AOP-AfterReturning] 返回值: " + result);
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}
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}</code></pre>
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</div>
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<div class="card">
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<h3>性能监控切面 (@Around)</h3>
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<pre><code>@Aspect
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@Component
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public class PerformanceAspect {
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@Around("execution(* com.example.demo..*.*(..))")
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public Object measureTime(ProceedingJoinPoint pjp) throws Throwable {
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long start = System.currentTimeMillis();
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try {
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Object result = pjp.proceed(); // 执行目标方法
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long duration = System.currentTimeMillis() - start;
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System.out.println("[AOP] " + pjp.getSignature() + " 耗时: " + duration + "ms");
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return result;
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} catch (Throwable e) {
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System.out.println("[AOP] 方法异常: " + e.getMessage());
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throw e;
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}
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}
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}</code></pre>
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</div>
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<div class="card">
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<h3>切入点表达式语法</h3>
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<pre><code>// 匹配任意公共方法
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execution(public * *(..))
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// 匹配 com.example 包下所有方法
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execution(* com.example.*.*(..))
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// 匹配 Controller 层所有方法
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execution(* com.example.demo.controller.*.*(..))
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// 匹配所有 Service 层的 save 开头的方法
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execution(* com.example.demo.service.*.save*(..))
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// 匹配带有 @Service 注解的类
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@within(org.springframework.stereotype.Service)
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// 匹配带有自定义注解的方法
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@annotation(com.example.demo.aop.RateLimited)</code></pre>
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</div>
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<h2>🎯 实际应用场景</h2>
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<div class="card">
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<table>
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<tr><th>场景</th><th>实现方式</th></tr>
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<tr><td>日志记录</td><td>@Before + @AfterReturning</td></tr>
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<tr><td>性能监控</td><td>@Around</td></tr>
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<tr><td>事务管理</td><td>@Around (Spring 已内置)</td></tr>
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<tr><td>权限检查</td><td>@Before</td></tr>
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<tr><td>限流控制</td><td>@Around + 自定义注解</td></tr>
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<tr><td>缓存</td><td>@Around (Spring Cache)</td></tr>
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</table>
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</div>
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<p style="margin-top: 30px;"><a href="/">← 返回学习中心</a></p>
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<script>
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const AOP_TASK_KEY = 'task.aop.done';
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function toggleAopTaskDone(el) {
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localStorage.setItem(AOP_TASK_KEY, el.checked ? '1' : '0');
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}
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function initAopTaskState() {
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const done = localStorage.getItem(AOP_TASK_KEY) === '1';
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const checkbox = document.getElementById('aopTaskDone');
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if (checkbox) checkbox.checked = done;
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}
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async function demoValidationError() {
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const box = document.getElementById('statsResult');
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box.textContent = '发送错误示例请求中...';
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try {
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const res = await fetch('/api/users', {
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method: 'POST',
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headers: { 'Content-Type': 'application/json' },
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body: JSON.stringify({ name: '', email: 'bad', age: 999 })
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});
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const data = await res.json();
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box.textContent = JSON.stringify(data, null, 2);
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} catch (e) {
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box.textContent = '错误: ' + e.message;
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}
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}
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async function loadStats() {
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const res = await fetch('/aop/stats');
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const data = await res.json();
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document.getElementById('statsResult').textContent = JSON.stringify(data, null, 2);
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}
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initAopTaskState();
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</script>
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</body>
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</html> |