4 EventListener接口
让我们继续看SocketConnector中的acceptConnect方法：
@Override
protected void acceptConnect() throws ConnectorException {
new Thread(() -> {
while (true && started) {
Socket socket = null;
try {
socket = serverSocket.accept();
LOGGER.info("新增连接：" + socket.getInetAddress() + ":" + socket.getPort());
} catch (IOException e) {
//单个Socket异常，不要影响整个Connector
LOGGER.error(e.getMessage(), e);
} finally {
IoUtils.closeQuietly(socket);
}
}
}).start();
}注意socket = serverSocket.accept()，这里获取到socket之后只是打印日志，并没获取socket的输入输出进行操作。
操作socket的输入和输出是否应该在SocketConnector中？
这时大师又说话了，Connector责任是啥，就是管理connect的啊，connect怎么使用，关它屁事。
再看那个无限循环，像不像再等待事件来临啊，成功accept一个socket就是一个事件，对scoket的使用，其实就是事件响应嘛。
OK，让我们按照这个思路来重构一下，目的就是加入事件机制，并将对具体实现的依赖控制在那几个工厂类里面去。
新增接口EventListener接口进行事件监听
public interface EventListener<T> {
/**
* 事件发生时的回调方法
* @param event 事件对象
* @throws EventException 处理事件时异常都转换为该异常抛出
*/
void onEvent(T event) throws EventException;
}为Socket事件实现一下，acceptConnect中打印日志的语句可以移动到这来
public class SocketEventListener implements EventListener<Socket> {
private static final Logger LOGGER = LoggerFactory.getLogger(SocketEventListener.class);
@Override
public void onEvent(Socket socket) throws EventException {
LOGGER.info("新增连接：" + socket.getInetAddress() + ":" + socket.getPort());
}重构Connector，添加事件机制，注意whenAccept方法调用了eventListener
public class SocketConnector extends Connector<Socket> {
... ...
private final EventListener<Socket> eventListener;
public SocketConnector(int port, EventListener<Socket> eventListener) {
this.port = port;
this.eventListener = eventListener;
}
@Override
protected void acceptConnect() throws ConnectorException {
new Thread(() -> {
while (true && started) {
Socket socket = null;
try {
socket = serverSocket.accept();
whenAccept(socket);
} catch (Exception e) {
//单个Socket异常，不要影响整个Connector
LOGGER.error(e.getMessage(), e);
} finally {
IoUtils.closeQuietly(socket);
}
}
}).start();
}
@Override
protected void whenAccept(Socket socketConnect) throws ConnectorException {
eventListener.onEvent(socketConnect);
}
... ...
}重构ServerFactory，添加对具体实现的依赖
public class ServerFactory {
public static Server getServer(ServerConfig serverConfig) {
List<Connector> connectorList = new ArrayList<>();
SocketEventListener socketEventListener = new SocketEventListener();
ConnectorFactory connectorFactory =
new SocketConnectorFactory(new SocketConnectorConfig(serverConfig.getPort()), socketEventListener);
connectorList.add(connectorFactory.getConnector());
return new SimpleServer(serverConfig, connectorList);
}
}再运行所有单元测试，一切都OK。
现在让我们来操作socket，实现一个echo功能的server吧。
直接添加到SocketEventListener中
public class SocketEventListener implements EventListener<Socket> {
private static final Logger LOGGER = LoggerFactory.getLogger(SocketEventListener.class);
@Override
public void onEvent(Socket socket) throws EventException {
LOGGER.info("新增连接：" + socket.getInetAddress() + ":" + socket.getPort());
try {
echo(socket);
} catch (IOException e) {
throw new EventException(e);
}
}
private void echo(Socket socket) throws IOException {
InputStream inputstream = null;
OutputStream outputStream = null;
try {
inputstream = socket.getInputStream();
outputStream = socket.getOutputStream();
Scanner scanner = new Scanner(inputstream);
PrintWriter printWriter = new PrintWriter(outputStream);
printWriter.append("Server connected.Welcome to echo.\n");
printWriter.flush();
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
if (line.equals("stop")) {
printWriter.append("bye bye.\n");
printWriter.flush();
break;
} else {
printWriter.append(line);
printWriter.append("\n");
printWriter.flush();
}
}
} finally {
IoUtils.closeQuietly(inputstream);
IoUtils.closeQuietly(outputStream);
}
}
}之前都是在单元测试里面启动Server的，这次需要启动Server后，用telnet去使用echo功能。
所以再为Server编写一个启动类，在其main方法里面启动Server
public class BootStrap {
public static void main(String[] args) throws IOException {
ServerConfig serverConfig = new ServerConfig();
Server server = ServerFactory.getServer(serverConfig);
server.start();
}
}服务器启动后，使用telnet进行验证，打开cmd，然后输入telnet localhost 端口，端口是ServerConfig里面的默认端口或者其他，回车就可以交互了。
到现在为止，我们的服务器终于有了实际功能，下一步终于可以去实现请求静态资源的功能了。
完整代码：https://github.com/pkpk1234/BeggarServletContainer/tree/step4
5 EventHandler接口和FileEventHandler实现
首先重构代码，让事件监听和事件处理分离开，各自责任更加独立。
否则想将Echo功能替换为返回静态文件，又需要到处改代码。
将责任分开后，只需要传入不同的事件处理器，即可实现不同效果。
增加EventHandler接口专门进行事件处理，SocketEventListener类中事件处理抽取到专门的EchoEventHandler实现中。
提出AbstractEventListener类，规定了事件处理的模板
public abstract class AbstractEventListener<T> implements EventListener<T> {
/**
* 事件处理流程模板方法
* @param event 事件对象
* @throws EventException
*/
@Override
public void onEvent(T event) throws EventException {
EventHandler<T> eventHandler = getEventHandler(event);
eventHandler.handle(event);
}
/**
* 返回事件处理器
* @param event
* @return
*/
protected abstract EventHandler<T> getEventHandler(T event);
}SocketEventListener重构为通过构造器传入事件处理器
public class SocketEventListener extends AbstractEventListener<Socket> {
private final EventHandler<Socket> eventHandler;
public SocketEventListener(EventHandler<Socket> eventHandler) {
this.eventHandler = eventHandler;
}
@Override
protected EventHandler<Socket> getEventHandler(Socket event) {
return eventHandler;
}
}EchoEventHandler实现Echo
public class EchoEventHandler extends AbstractEventHandler<Socket> {
@Override
protected void doHandle(Socket socket) {
InputStream inputstream = null;
OutputStream outputStream = null;
try {
inputstream = socket.getInputStream();
outputStream = socket.getOutputStream();
Scanner scanner = new Scanner(inputstream);
PrintWriter printWriter = new PrintWriter(outputStream);
printWriter.append("Server connected.Welcome to echo.\n");
printWriter.flush();
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
if (line.equals("stop")) {
printWriter.append("bye bye.\n");
printWriter.flush();
break;
} else {
printWriter.append(line);
printWriter.append("\n");
printWriter.flush();
}
}
} catch (IOException e) {
throw new HandlerException(e);
} finally {
IoUtils.closeQuietly(inputstream);
IoUtils.closeQuietly(outputStream);
}
}
}再次将对具体实现的依赖限制到Factory中
public class ServerFactory {
/**
* 返回Server实例
*
* @return
*/
public static Server getServer(ServerConfig serverConfig) {
List<Connector> connectorList = new ArrayList<>();
//传入Echo事件处理器
SocketEventListener socketEventListener = new SocketEventListener(new EchoEventHandler());
ConnectorFactory connectorFactory =
new SocketConnectorFactory(new SocketConnectorConfig(serverConfig.getPort()), socketEventListener);
connectorList.add(connectorFactory.getConnector());
return new SimpleServer(serverConfig, connectorList);
}
}执行单元测试，一切正常。运行Server，用telnet进行echo，也是正常的。
现在添加返回静态文件功能。功能大致如下：
- 服务器使用user.dir作为根目录。
- 控制台输入文件路径，如果文件是目录，则打印目录中的文件列表；如果文件不是目录，且可读，则返回文件内容;如果不满足前面两种场景，返回文件找不到
新增FileEventHandler
public class FileEventHandler extends AbstractEventHandler<Socket>{
private final String docBase;
public FileEventHandler(String docBase) {
this.docBase = docBase;
}
@Override
protected void doHandler(Socket socket) {
getFile(socket);
}
private void getFile(Socket socket) {
InputStream inputStream = null;
OutputStream outputStream = null;
try{
inputStream = socket.getInputStream();
outputStream = socket.getOutputStream();
Scanner scanner = new Scanner(inputStream, "UTF-8");
PrintWriter printWriter = new PrintWriter(outputStream);
printWriter.append("Server connected.Welcome to File Server.\n");
printWriter.flush();
while (scanner.hasNextLine()){
String line = scanner.nextLine();
if(line.equals("stop")){
printWriter.append("bye bye.\n");
printWriter.flush();
break;
}else {
Path filePath = Paths.get(this.docBase, line);
if(Files.isDirectory(filePath)){
printWriter.append("目录 ").append(filePath.toString()).append(" 下有文件: ").append("\n");
try{
DirectoryStream<Path> stream = Files.newDirectoryStream(filePath);
for (Path path: stream){
printWriter.append(path.getFileName().toString()).append("\n").flush();
}
}catch(IOException e){
e.printStackTrace();
}
//如果文件可读，就打印文件内容
} else if(Files.isReadable(filePath)){
printWriter.append("File: ").append(filePath.toString()).append(" 的内容是: ").append("\n").flush();
Files.copy(filePath, outputStream);
printWriter.append("\n");
//其他情况返回文件找不到
} else {
printWriter.append("File ").append(filePath.toString())
.append(" is not found.").append("\n").flush();
}
}
}
}catch (IOException e) {
throw new HandlerException(e);
} finally {
IoUtils.closeQuietly(inputStream);
IoUtils.closeQuietly(outputStream);
}
}
}修改ServerFactory，使用FileEventHandler
public class ServerFactory {
/**
* 返回Server实例
* @return
*/
public static Server getServer(ServerConfig serverConfig) {
List<Connector> connectorList = new ArrayList<>();
//EventHandler eventHandler =new EchoEventHandler();
EventHandler eventHandler = new FileEventHandler(System.getProperty("user.dir"));
SocketEventListener socketEventListener = new SocketEventListener(eventHandler);
ConnectorFactory connectorFactory = new SocketConnectorFactory(new SocketConnectorConfig(serverConfig.getPort()), socketEventListener);
connectorList.add(connectorFactory.getConnector());
return new SimpleServer(serverConfig, connectorList);
}
}运行BootStrap启动Server进行验证：
绿色框：输入回车，返回目录下文件列表。
黄色框：输入README.MD，返回文件内容
蓝色框：输入不存在的文件，返回文件找不到。
完整代码：https://github.com/pkpk1234/BeggarServletContainer/tree/step5
