Netty核心组件介绍及手写简易版Tomcat详解程序员

//Netty就是一个同时支持多协议的网络通信框架 
public class WuzzTomcat { 
//打开Tomcat源码，全局搜索ServerSocket 
private int port = 8080; 
private Map<String, WuzzServlet> servletMapping = new HashMap<String, WuzzServlet>(); 
private Properties webxml = new Properties(); 
private void init() { 
//加载web.xml文件,同时初始化 ServletMapping对象 
try { 
String WEB_INF = this.getClass().getResource("/").getPath(); 
FileInputStream fis = new FileInputStream(WEB_INF + "web.properties");
　　　　　　  //加载配置文件 
webxml.load(fis); 
for (Object k : webxml.keySet()) { 
String key = k.toString(); 
if (key.endsWith(".url")) { 
String servletName = key.replaceAll("//.url$", ""); 
String url = webxml.getProperty(key); 
String className = webxml.getProperty(servletName + ".className"); 
WuzzServlet obj = (WuzzServlet) Class.forName(className).newInstance(); 
servletMapping.put(url, obj); 
} 
} 
} catch (Exception e) { 
e.printStackTrace(); 
} 
} 
public void start() { 
init(); 
//Netty封装了NIO，Reactor模型，Boss，worker 
// Boss线程 
EventLoopGroup bossGroup = new NioEventLoopGroup(); 
// Worker线程 
EventLoopGroup workerGroup = new NioEventLoopGroup(); 
try { 
// Netty服务 
//ServetBootstrap   ServerSocketChannel 
ServerBootstrap server = new ServerBootstrap(); 
// 链路式编程 
            server.group(bossGroup, workerGroup) 
// 主线程处理类,看到这样的写法，底层就是用反射 
.channel(NioServerSocketChannel.class) 
// 子线程处理类 , Handler 
.childHandler(new ChannelInitializer<SocketChannel>() { 
// 客户端初始化处理 
protected void initChannel(SocketChannel client) throws Exception { 
// 无锁化串行编程 
//Netty对HTTP协议的封装，顺序有要求 
// HttpResponseEncoder 编码器 
client.pipeline().addLast(new HttpResponseEncoder()); 
// HttpRequestDecoder 解码器 
client.pipeline().addLast(new HttpRequestDecoder()); 
// 业务逻辑处理 
client.pipeline().addLast(new WuzzTomcatHandler()); 
} 
}) 
// 针对主线程的配置 分配线程最大数量 128 
.option(ChannelOption.SO_BACKLOG, 128) 
// 针对子线程的配置 保持长连接 
.childOption(ChannelOption.SO_KEEPALIVE, true); 
// 启动服务器 
ChannelFuture f = server.bind(port).sync(); 
System.out.println("Wuzz Tomcat 已启动，监听的端口是：" + port); 
f.channel().closeFuture().sync(); 
} catch (Exception e) { 
e.printStackTrace(); 
} finally { 
// 关闭线程池 
            bossGroup.shutdownGracefully(); 
workerGroup.shutdownGracefully(); 
} 
}public static void main(String[] args) { 
new WuzzTomcat().start(); 
} 
}

servlet.one.url=/firstServlet.do 
servlet.one.className=com.wuzz.demo.netty.tomcat.servlet.FirstServlet 
servlet.two.url=/secondServlet.do 
servlet.two.className=com.wuzz.demo.netty.tomcat.servlet.SecondServlet

public abstract class WuzzServlet { 
　　public void service(WuzzRequest request, WuzzResponse response) throws Exception{ 
//由service方法来决定，是调用doGet或者调用doPost 
if("GET".equalsIgnoreCase(request.getMethod())){ 
doGet(request, response); 
}else{ 
doPost(request, response); 
} 
} 
public abstract void doGet(WuzzRequest request, WuzzResponse response) throws Exception; 
public abstract void doPost(WuzzRequest request, WuzzResponse response) throws Exception; 
}
 
public class FirstServlet extends WuzzServlet { 
@Override 
public void doGet(WuzzRequest request, WuzzResponse response) throws Exception { 
this.doPost(request, response); 
} 
@Override 
public void doPost(WuzzRequest request, WuzzResponse response) throws Exception { 
response.write("This is First Serlvet"); 
} 
}
 
public class SecondServlet extends WuzzServlet { 
@Override 
public void doGet(WuzzRequest request, WuzzResponse response) throws Exception { 
this.doPost(request, response); 
} 
@Override 
public void doPost(WuzzRequest request, WuzzResponse response) throws Exception { 
response.write("This is Second Serlvet"); 
} 
}

public class WuzzRequest { 
private ChannelHandlerContext ctx; 
private HttpRequest req; 
public WuzzRequest(ChannelHandlerContext ctx, HttpRequest req) { 
this.ctx = ctx; 
this.req = req; 
} 
public String getUrl() { 
return req.uri(); 
} 
public String getMethod() { 
return req.method().name(); 
} 
}

public class WuzzResponse { 
//SocketChannel的封装 
private ChannelHandlerContext ctx; 
private HttpRequest req; 
public WuzzResponse(ChannelHandlerContext ctx, HttpRequest req) { 
this.ctx = ctx; 
this.req = req; 
} 
public void write(String out) throws Exception { 
try { 
if (out == null || out.length() == 0) { 
return; 
} 
// 设置 http协议及请求头信息 
FullHttpResponse response = new DefaultFullHttpResponse( 
// 设置http版本为1.1 
                HttpVersion.HTTP_1_1, 
// 设置响应状态码 
                HttpResponseStatus.OK, 
// 将输出值写出 编码为UTF-8 
Unpooled.wrappedBuffer(out.getBytes("UTF-8"))); 
response.headers().set("Content-Type", "text/html;"); 
// 当前是否支持长连接 
//            if (HttpUtil.isKeepAlive(r)) { 
//                // 设置连接内容为长连接 
//                response.headers().set(CONNECTION, HttpHeaderValues.KEEP_ALIVE); 
//            } 
            ctx.write(response); 
} finally { 
ctx.flush(); 
ctx.close(); 
} 
} 
}

 //业务处理handler 
public class WuzzTomcatHandler extends ChannelInboundHandlerAdapter { 
@Override 
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { 
if (msg instanceof HttpRequest) { 
HttpRequest req = (HttpRequest) msg; 
// 转交给我们自己的request实现 
WuzzRequest request = new WuzzRequest(ctx, req); 
// 转交给我们自己的response实现 
WuzzResponse response = new WuzzResponse(ctx, req); 
// 实际业务处理 
String url = request.getUrl(); 
if (servletMapping.containsKey(url)) { 
servletMapping.get(url).service(request, response); 
} else { 
response.write("404 - Not Found"); 
} 
} 
} 
　　　　　//异常处理 
        @Override 
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { 
} 
}