JAVA小白进阶day20

于 2020-08-12 22:54:09 发布
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本文链接：https://blog.youkuaiyun.com/hyj_123/article/details/107942994
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Java注解复习

Bean.java
@Target(ElementType.TYPE) //可以作用在接口、类、枚举、注解
@Retention(RetentionPolicy.RUNTIME)
public @interface Bean {
	public String id();
}

Property.java
@Target(ElementType.FIELD) 
@Retention(RetentionPolicy.RUNTIME)
public @interface Property {
	String ref();
}

EmapDao.java
@Bean(id = "empDao")
public class EmpDao {
	public  void insert() {
		System.out.println("insert....");
	}
}

EmpService.java
@Bean(id="empService")
public class EmpService {
	@Property(ref="empDao")
	private EmpDao empDao;
	public void addEmp() {
		empDao.insert();
	}
}

BeanFactory.java
public class BeanFactory {
	private static Map<String, Object> map = new HashMap<>();
	static {
		try {
			init();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	public static void init() throws Exception {
		// 解析xml为文件，获取包路径
		SAXReader reader = new SAXReader();
		Document document = reader.read("config/Test0811.xml");
		Element root = document.getRootElement();
		Element e = root.element("context-scan");
		String packageName = e.attributeValue("package");
		// 获取该路径下的文件D:\SubjectSoftware\MyEclipse\eclipse-workspace\hhh0810\Demo0811
//		Properties p = System.getProperties();
//		System.out.println(p);
//		System.out.println();
		String path = System.getProperty("user.dir") + "\\src\\" + packageName;
//		System.out.println(path);
//		System.out.println(System.getProperty("user.dir"));//获取工作目录
		File file = new File(path);
		File[] files = file.listFiles();// 获取所有文件和文件夹
		for (File f : files) {
			if (f.isFile()) {
				// EmpDao.java用点将类名读到
				String fileName = f.getName().substring(0, f.getName().indexOf("."));
				String className = packageName + "." + fileName;
				Class<?> class1 = Class.forName(className);
				if (class1.isAnnotationPresent(Bean.class)) {
					Bean bean = class1.getAnnotation(Bean.class);
					String id = bean.id();
					map.put(id, class1.newInstance());
				}
			}
		}
		for (File f : files) {
			if (f.isFile()) {
				// EmpDao.java用点将类名读到
				String fileName = f.getName().substring(0, f.getName().indexOf("."));
				String className = packageName + "." + fileName;
				Class<?> class1 = Class.forName(className);
				if (class1.isAnnotationPresent(Bean.class)) {
					Bean bean = class1.getAnnotation(Bean.class);
					String id = bean.id();
					//获取所有成员变量
					Field[] fields = class1.getDeclaredFields();
					for(Field field:fields) {
						if(field.isAnnotationPresent(Property.class)) {
							Property p = field.getAnnotation(Property.class);
							field.setAccessible(true);
							//map.get(id)表示当前类对象
							//map.get(p.ref())表示成员变量的类型的对象
							field.set(map.get(id),map.get(p.ref()));
						}
					}
					
				}
			}
		}
	}
	public static Object getBean(String key) {
		return map.get(key);
	}

	public static void main(String[] args) {
		System.out.println(map);
	}
}

Test.java
public class Test {
	public static void main(String[] args) {
		EmpService empService = (EmpService)BeanFactory.getBean("empService");
		empService.addEmp();
	}
}

模拟客户端和服务器之间的交互

第一个版本
写服务器端，多线程的服务器端（ClientHandler）
1.包：cn.tedu.core
2.类名：WebServer
3.声明成员变量：
server：ServerSocket
4.方法：
无参的构造方法：WebServer
功能：初始化server，端口号为8080
start方法：
功能：启动服务器
接收客户端请求：accept（）
定义线程对象，并启动线程start（）
5.定义内部类:ClientHandler
线程类定义成员变量：socket：Socket
定义带参的构造方法初始化：socket
重写run方法：功能：控制台输出处理客户端请求
6.定义main方法：启动服务器
7.测试：打开浏览器客户端：http://localhost:8888

public class WebServer_v1 {
	ServerSocket server;

	public WebServer_v1() {
		try {
			server = new ServerSocket(8888);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public void start() {
		while (true) {
			Socket socket;
			try {
				while (true) {
					System.out.println("等待客户端的请求");
					socket = server.accept();
					new Thread(new ClientHandler(socket)).start();
				}
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

	class ClientHandler implements Runnable {
		Socket socket;
		public ClientHandler() {
		}
		public ClientHandler(Socket socket) {
			this.socket = socket;
		}
		@Override
		public void run() {
			System.out.println("接收客户端请求");
			
		}
	}

	public static void main(String[] args) {
		new WebServer_v1().start();
	}

}

第二个版本
1.读客户端的请求
在run方法处理客户端请求
1）获取InputStream对象
2）使用read方法读取数据，判断如果!=-1,输出
int d = -1;
while((d= in.read())!=-1){
System.out.print((char)d);
}
3）观察打印结果：学习http协议请求头信息格式
2.解析请求行：使用StringBuilder存放

StringBuilder builder = new StringBuilder();
		int d = -1;
		char c1 = 0,c2=0;
		while((d= in.read())!=-1){
			c2 = (char)d;
			if(c1== 13 && c2 == 10){
				break; 
			}
			builder.append(c2);
			c1 = c2;
			}
		System.out.println(builder.toString().trim());
		in.close();

2)测试：打开浏览器客户端：http://localhost:8080/myweb/index.html
3.解析url，并打印输出

public class WebServer_v2 {
	ServerSocket server;
	public WebServer_v2() {
		try {
			server = new ServerSocket(8888);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	public void start() {
		while (true) {
			Socket socket;
			try {
				while (true) {
					System.out.println("等待客户端的请求");
					socket = server.accept();
					new Thread(new ClientHandler(socket)).start();
				}
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	
	class ClientHandler implements Runnable {
		Socket socket;
		public ClientHandler() {
		}
		public ClientHandler(Socket socket) {
			this.socket = socket;
		}
		@Override
		public void run() {
			//  \r\n ASCⅡ 13 10
			System.out.println("接收客户端请求");
			//获取请求状态行
			try {
				InputStream in =  socket.getInputStream();
				StringBuilder builder = new StringBuilder();
				char c1 = 0,c2 = 0;
				int d = -1;
				while((d=in.read())!=-1) {
					c2 = (char)d;
					//解析第一行,遇到 \r\n，break
					if(c1 == 13 && c2 == 10) {
						break;
					}
					builder.append(c2);
					c1 = c2;
				}
				String str = builder.toString().trim();//去掉字符串两端的多余的空格,
				String[] data = str.split(" ");//用空格分隔开str,并存入数组中
				System.out.println(data[0]);//获取请求方式get
				System.out.println(data[1]);//url请求
				System.out.println(data[2]);//协议名称
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	public static void main(String[] args) {
		new WebServer_v2().start();
	}
}

第三个任务：
1.定义HttpRequest类
1）定义HttpRequest类在com.tedu.http包中
2）定义变量：method，url，protocol；
3）定义带参的构造方法HttpRequest(InputStream in)
4）定义三个变量的get方法
5）定义方法：parseRquestLine(InputStream in)：void
方法的功能：解析请求行，给三个变量赋值
在构造方法中调用
2.重构WebServer的run方法
创建HttpRequest对象，调用get方法打印请求的方法，url，protocl
3.测试：打开浏览器客户端：http://localhost:8888/myweb/index.html

public class WebServer {
	ServerSocket server;
	public WebServer() {
		try {
			server = new ServerSocket(8888);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	public void start() {
		while (true) {
			Socket socket;
			try {
				while (true) {
					System.out.println("等待客户端的请求");
					socket = server.accept();
					new Thread(new ClientHandler(socket)).start();
				}
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

	class ClientHandler implements Runnable {
		Socket socket;
		public ClientHandler() {
		}
		public ClientHandler(Socket socket) {
			this.socket = socket;
		}
		@Override
		public void run() {
			//  \r\n ASCⅡ 13 10
			System.out.println("接收客户端请求");
			//获取请求状态行
			try {
				InputStream in =  socket.getInputStream();
				HttpRequest request =new HttpRequest(in);
				System.out.println(request.getMethod());
				System.out.println(request.getUrl());
				System.out.println(request.getProtocol());
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	public static void main(String[] args) {
		new WebServer().start();
	}
]
}

第四个任务
读文件，响应文件到客户端
1.在项目中添加目录webapps,并在里面添加一个子目录myweb,然后在其中存放我们定义的页面index.html
2.响应包括两部分，响应头和响应文件
3.学习掌握响应头信息
4.响应画面到客户端
1）读文件：通过url File file = new File(“webapps”+request.getUrl());
2）获取输出流
3）通过输出流写响应头信息

public class WebServer {
	ServerSocket server;
	public WebServer() {
		try {
			server = new ServerSocket(8888);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	public void start() {
		while (true) {
			Socket socket;
			try {
				while (true) {
					System.out.println("等待客户端的请求");
					socket = server.accept();
					new Thread(new ClientHandler(socket)).start();
				}
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

	class ClientHandler implements Runnable {
		Socket socket;
		public ClientHandler() {
		}
		public ClientHandler(Socket socket) {
			this.socket = socket;
		}
		@Override
		public void run() {
			//  \r\n ASCⅡ 13 10
			System.out.println("接收客户端请求");
			//获取请求状态行
			try {
				InputStream in =  socket.getInputStream();
				OutputStream out = socket.getOutputStream();
				HttpRequest request =new HttpRequest(in);
//				System.out.println(request.getMethod());
//				System.out.println(request.getUrl());
//				System.out.println(request.getProtocol());
				File file = new File("webapps"+request.getUrl());
				//响应页面
				//状态行
				out.write("HTTP/1.1 200 OK".getBytes());
				out.write(13);
				out.write(10);
				//响应头信息
				out.write("Content-Type:text/html".getBytes());
				out.write(13);
				out.write(10);
				out.write(("Content-Length:"+file.length()).getBytes());
				out.write(13);
				out.write(10);
				//空行
				out.write(13);
				out.write(10);
				//响应的文档内容
				FileInputStream fin = new FileInputStream(file);
				byte[] buffer = new byte[(int)file.length()];
				fin.read(buffer);
				out.write(buffer);
				fin.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	public static void main(String[] args) {
		new WebServer().start();
	}
}

public class HttpRequest {
	public String method;
	public String url;
	public String protocol;
	public HttpRequest() {}
	public HttpRequest(InputStream in) {
		try {
			parseRequestLine(in);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	public String getMethod() {
		return method;
	}
	public String getUrl() {
		return url;
	}
	public String getProtocol() {
		return protocol;
	}
	public void parseRequestLine(InputStream in) throws IOException {
		StringBuilder builder = new StringBuilder();
		char c1 = 0,c2 = 0;
		int d = -1;
		while((d=in.read())!=-1) {
			c2 = (char)d;
			//解析第一行,遇到 \r\n，break
			if(c1 == 13 && c2 == 10) {
				break;
			}
			builder.append(c2);
			c1 = c2;
		}
		String str = builder.toString().trim();
		String[] data = str.split(" ");
		this.method = data[0];//获取请求方式get
		this.url = data[1];//url请求
		this.protocol = data[2];//协议名称
	}
}
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