feat(springDemo): 添加 Server-Sent Events (SSE) 功能和代理演示

- 新增 SSEEmitter 类实现 Server-Sent Events功能 - 添加 ProxyDemo 类演示动态代理 - 更新 UserService 类，增加 Bean 生命周期相关注释 - 调整 application.yaml 文件格式
2024-10-22 23:23:03 +08:00 · 2024-10-22 23:23:03 +08:00 · 25f4784daa
commit 25f4784daa
parent 72843c9027
4 changed files with 191 additions and 11 deletions
--- a/ForJdk8/src/main/java/cn/whaifree/tech/proxy/ProxyDemo.java
+++ b/ForJdk8/src/main/java/cn/whaifree/tech/proxy/ProxyDemo.java
@ -0,0 +1,46 @@
+package cn.whaifree.tech.proxy;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/10/22 23:13
+ * @注释
+ */
+public class ProxyDemo {
+
+    interface base{
+        void print();
+    }
+
+    static class A implements base {
+
+        @Override
+        public void print() {
+            System.out.println("A");
+        }
+    }
+
+
+    public static void main(String[] args) {
+        base a = (base)
+                java.lang.reflect.Proxy.newProxyInstance(
+                        base.class.getClassLoader(),
+                        new Class[]{
+                                base.class
+                        },
+                        new InvocationHandler() {
+                            @Override
+                            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+                                System.out.println("ProxyA");
+                                method.invoke(new A(), args);
+                                System.out.println("after invoke");
+                                return null;
+                            }
+                        }
+                );
+        a.print();
+    }
+}
--- a/springDemo/src/main/java/cn/whaifree/springdemo/controller/SSE/SSEEmitter.java
+++ b/springDemo/src/main/java/cn/whaifree/springdemo/controller/SSE/SSEEmitter.java
@ -0,0 +1,55 @@
+package cn.whaifree.springdemo.controller.SSE;
+
+import cn.hutool.core.util.StrUtil;
+import org.springframework.http.MediaType;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
+
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/10/22 21:44
+ * @注释
+ */
+@RestController
+public class SSEEmitter {
+
+    public static void main(String[] args) {
+        int a = 127;
+        byte c = (byte) a;
+        System.out.println(Integer.toBinaryString(c));
+        System.out.println(c);
+    }
+    Map<String, SseEmitter> sseEmitterMap = new java.util.HashMap<>();
+
+    @GetMapping(value = "/sseStart", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
+    public SseEmitter sse(String key) {
+        System.out.println(key);
+        if (!sseEmitterMap.containsKey(key)) {
+            SseEmitter sseEmitter = new SseEmitter();
+            sseEmitterMap.put(key, sseEmitter);
+        }
+
+        return sseEmitterMap.get(key);
+    }
+
+    @PostMapping("sendSSE")
+    public void send(String key, String message) {
+        if (sseEmitterMap.containsKey(key)) {
+            SseEmitter sseEmitter = sseEmitterMap.get(key);
+            try {
+                System.out.println(StrUtil.format("send message to {}:{}", key, message));
+                sseEmitter.send(message);
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }else {
+            throw new IllegalArgumentException("No such key");
+        }
+    }
+}
--- a/springDemo/src/main/java/cn/whaifree/springdemo/entity/UserService.java
+++ b/springDemo/src/main/java/cn/whaifree/springdemo/entity/UserService.java
@ -1,12 +1,10 @@
 package cn.whaifree.springdemo.entity;

+
 import jakarta.annotation.PostConstruct;
 import jakarta.annotation.PreDestroy;
 import org.springframework.beans.BeansException;
-import org.springframework.beans.factory.BeanFactory;
-import org.springframework.beans.factory.BeanFactoryAware;
-import org.springframework.beans.factory.DisposableBean;
-import org.springframework.beans.factory.InitializingBean;
+import org.springframework.beans.factory.*;
 import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
@ -22,11 +20,53 @@ import org.springframework.core.annotation.Order;
 */
@Configuration
@Order(-1)
-class Config{
+class Config {

 }
-//@Component("userService")
-public class UserService implements InitializingBean, DisposableBean, BeanFactoryAware, ApplicationContextAware, BeanPostProcessor,AutoCloseable {
+
+/**
+ * <h1>Spring Bean生命周期</h1>
+ * <p>Spring Bean 的生命周期包括创建、初始化、使用、销毁等过程。</p>
+ * <p>Spring Bean 的生命周期</p>
+ *
+*      <li>实例化阶段：Bean 被实例化，Bean 实例化后，Bean 处于未初始化状态。</li>
+*       <li>初始化阶段：Bean 完成实例化后，Bean 处于初始化状态，Bean 实例变量可以被赋值。</li>
+*       <ul>
+*           <li><code>BeanNameAware.setBeanName</code></li>
+*           <li><code>BeanFactoryAware.setBeanFactory</code></li>
+*           <li><code>ApplicationContextAware.setApplicationContext</code></li>
+*       </ul>
+*     <ul>
+*         <li><code>@PostConstruct</code></li>
+*         <li><code>InitializingBean.afterPropertiesSet</code></li>
+*         <li><code>BeanPostProcessor.postProcessBeforeInitialization</code></li>
+*         <li>初始化</li>
+*         <li><code>BeanPostProcessor.postProcessAfterInitialization</code></li>
+*     </ul>
+*        <li>使用阶段：Bean 完成初始化后，Bean 处于可使用状态，Bean 可以被使用。</li>
+*         <li>销毁阶段：Bean 不再被使用时，Bean 处于销毁状态，Bean 实例将被销毁。</li>
+*
+*          <ul>
+*          <li><code>@PreDestroy</code></li>
+*          <li><code>DisposableBean.destroy</code></li>
+*
+*
+*
+*      </ul>
+*
+ *
+ *
+ *
+ *
+ * <h2>相关Aware注入：让 Bean 能够**感知**到它们所运行的环境或依赖的资源e</h2>
+ * <h2>为什么要叫Aware</h2>
+ * Aware是一个接口，
+ * 指示 Bean 有资格通过 Callback 样式方法由 Spring 容器通知特定框架对象。
+ * 实际的方法签名由各个子接口确定，但通常应仅包含一个接受单个参数的返回 void 的方法
+ */
+//@Component
+public class UserService implements InitializingBean, DisposableBean, BeanNameAware, BeanFactoryAware, ApplicationContextAware, BeanPostProcessor, AutoCloseable {
+

    /**
     * 执行 BeanFactoryAware.setBeanFactory
@ -43,14 +83,17 @@ public class UserService implements InitializingBean, DisposableBean, BeanFactor
    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext("cn.whaifree.springdemo.entity");
        UserService userService = context.getBean("userService", UserService.class);
+        System.out.println(userService);
        // 执行 DisposableBean

        context.close();
    }
+
    private String beanName;
    private BeanFactory beanFactory;
    private ApplicationContext applicationContext;

+
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("执行 BeanPostProcessor.postProcessBeforeInitialization");
@ -73,25 +116,39 @@ public class UserService implements InitializingBean, DisposableBean, BeanFactor
        System.out.println("UserService destroy");
    }

+    /**
+     * org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#invokeAwareMethods(java.lang.String, java.lang.Object)
+     *
+     * if (bean instanceof BeanFactoryAware beanFactoryAware) { // 如果实现了BeanFactoryAware接口，就执行setBeanFactory
+     * 	beanFactoryAware.setBeanFactory(AbstractAutowireCapableBeanFactory.this);
+     *   }
+     * @param beanFactory owning BeanFactory (never {@code null}).
+     * The bean can immediately call methods on the factory.
+     * @throws BeansException
+     */
    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        this.beanFactory = beanFactory;
        System.out.println("执行 BeanFactoryAware.setBeanFactory");
    }

+
+
+
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
-        System.out.println("执行 ApplicationContextAware.setApplicationContext");
+        System.out.println("ApplicationContextAware.setApplicationContext(ApplicationContext applicationContext) 可以获取applicantionContext，便于获取context，可以提取变成一个公共的component，每次从这个component获取Bean");
    }

+
    @PostConstruct
-    public void init(){
+    public void init() {
        System.out.println("执行 @PostConstruct");
    }

    @PreDestroy
-    public void destroyMethod(){
+    public void destroyMethod() {
        System.out.println("执行 @PreDestroy");
    }

@ -100,6 +157,12 @@ public class UserService implements InitializingBean, DisposableBean, BeanFactor

    }

+    @Override
+    public void setBeanName(String name) {
+        System.out.println("执行 BeanNameAware.setBeanName");
+        // 修改原来的BeanName
+    }
+

    /**
     * org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#invokeAwareMethods(java.lang.String, java.lang.Object)
@ -107,7 +170,7 @@ public class UserService implements InitializingBean, DisposableBean, BeanFactor
     * if (bean instanceof Aware) {
     * 			if (bean instanceof BeanNameAware beanNameAware) {
     * 				beanNameAware.setBeanName(beanName);
-     * 			            }
+     *                        }
     * 			if (bean instanceof BeanClassLoaderAware beanClassLoaderAware) {
     * 				ClassLoader bcl = getBeanClassLoader();
     * 				if (bcl != null) {
@ -121,3 +184,18 @@ public class UserService implements InitializingBean, DisposableBean, BeanFactor


 }
+
+/**
+ * 模拟工具类，其实就是可以随时获取本Context
+ */
+//@Component
+//class SpringContextUtil implements ApplicationContextAware {
+//    static ApplicationContext applicationContext;
+//    @Override
+//    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
+//        this.applicationContext = applicationContext;
+//    }
+//    public static ApplicationContext getApplicationContext(){
+//        return applicationContext;
+//    }
+//}
--- a/springDemo/src/main/resources/application.yaml
+++ b/springDemo/src/main/resources/application.yaml
@ -8,6 +8,7 @@ spring:

  data:
    redis:
+
      host: localhost
      port: 6379
      # 选择db1