基于netty手写Tomcat

netty 简介

Netty一个基于NIO的客户、服务器端的编程框架

1.环境准备

maven依赖

<groupId>io.netty</groupId>

<artifactId>netty-all</artifactId>

<version>4.1.42.Final</version>

</dependency>

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RequestMethodEnum 请求方式

public enum RequestMethodEnum {

GET("GET"),

POST("POST");

public String code;

RequestMethodEnum(String code) {

this.code=code;

}

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ParentServlet 父类servlet

public abstract class ParentServlet {

public void service(ParentRequest request, ParentResponse response) throws Exception {

//service 方法决定调用doGet、doPost；

if (RequestMethodEnum.GET.code.equalsIgnoreCase(request.getMethod())) {

doGet(request, response);

} else {

doPost(request, response);

}

protected abstract void doPost(ParentRequest request, ParentResponse response) throws Exception;

protected abstract void doGet(ParentRequest request, ParentResponse response) throws Exception;

}

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FirstServlet

public class FirstServlet extends ParentServlet {

@Override

protected void doPost(ParentRequest request, ParentResponse response) throws Exception {

response.write("This is the first");

}

@Override

protected void doGet(ParentRequest request, ParentResponse response) throws Exception {

this.doPost(request,response);

}

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SecondServlet

public class SecondServlet extends ParentServlet {

@Override

protected void doPost(ParentRequest request, ParentResponse response) throws Exception {

response.write("this is the second");

}

@Override

protected void doGet(ParentRequest request, ParentResponse response) throws Exception {

this.doPost(request,response);

}

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ParentRequest

public class ParentRequest {

private String method;

private String url;

public String getUrl() {

return url;

}

public String getMethod() {

return method;

}

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ParentResponse

public class ParentResponse {

private OutputStream out;

public ParentResponse (OutputStream out) {

this.out = out;

}

public void write(String s) throws Exception{

//输出也要遵循HTTP

//状态码为200

StringBuilder sb = new StringBuilder();

sb.append("HTTP/1.1 200 OK \n")

.append("Content-Type: text/html;\n")

.append("\r\n")

.append(s);

out.write(sb.toString().getBytes());

}

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web.properties

servlet.first.url=/first

servlet.first.className=com.aiden.servlet.FirstServlet

servlet.second.url=/second

servlet.second.className=com.aiden.servlet.SecondServlet

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2.基于传统I/O手写Tomcat

修改ParentRequest

public class ParentRequest {

private String method;

private String url;

public ParentRequest(InputStream in) {

try {

String content = "";

byte[] buff = new byte[1024];

int len = 0;

if ((len = in.read(buff)) > 0) {

content = new String(buff,0,len);

}

String line = content.split("\\n")[0];

String [] arr = line.split("\\s");

this.method = arr[0];

System.out.println(method);

this.url = arr[1].split("\\?")[0];

} catch (IOException e) {

e.printStackTrace();

}

public String getUrl() {

return url;

}

public String getMethod() {

return method;

}

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编写tomcatStart类

public class TomcatStart {

private int port = 8080;

private ServerSocket server;

private Map<String, ParentServlet> servletMapping = new HashMap<String, ParentServlet>();

private Properties webProperties = new Properties();

private void init() {

try {

String WEB_INF = this.getClass().getResource("/").getPath();

FileInputStream fis = new FileInputStream(WEB_INF + "web.properties");

webProperties.load(fis);

for (Object k : webProperties.keySet()) {

String key = k.toString();

if (key.endsWith(".url")) {

String servletName = key.replaceAll("\\.url$", "");

String url = webProperties.getProperty(key);

String className = webProperties.getProperty(servletName + ".className");

//单实例多线程

ParentServlet obj = (ParentServlet) Class.forName(className).newInstance();

servletMapping.put(url, obj);

}

} catch (Exception e) {

e.printStackTrace();

}

public void start() {

//1.加载配置类，初始化servletMapping

init();

try {

//2.绑定端口启动

server = new ServerSocket(this.port);

System.out.println("Tomcat 已启动，监听端口是：" + this.port);

//3.等待用户请求，用一个死循环

while (true) {

Socket client = server.accept();

//4.http 请求

process(client);

}

} catch (IOException e) {

e.printStackTrace();

}

private void process(Socket client) throws IOException {

InputStream is = null;

OutputStream os = null;

try {

is = client.getInputStream();

os = client.getOutputStream();

//5.Request(inputstream) Response (outputstream)

ParentRequest request = new ParentRequest(is);

ParentResponse response = new ParentResponse(os);

//6.从协议内容中获取url 映射相应的servlet

String url = request.getUrl();

if (servletMapping.containsKey(url)) {

//7.调用实例化对象的service方法

servletMapping.get(url).service(request, response);

} else {

response.write("404 - Not Found");

}

} catch (Exception e) {

e.printStackTrace();

} finally {

if (os != null) {

os.flush();

os.close();

}

if (is != null) {

is.close();

}

client.close();

}

public static void main(String[] args) {

//启动

new TomcatStart().start();

}

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3.基于netty手写Tomcat

修改ParentRequest

public class ParentRequest {

private ChannelHandlerContext ctx;

private HttpRequest req;

public ParentRequest(ChannelHandlerContext ctx, HttpRequest req) {

this.ctx = ctx;

this.req = req;

}

public String getUrl() {

return req.uri();

}

public String getMethod() {

return req.method().name();

}

public Map<String, List<String>> getParameters() {

QueryStringDecoder decoder = new QueryStringDecoder(req.uri());

return decoder.parameters();

}

public String getParameter(String name) {

Map<String, List<String>> params = getParameters();

List<String> param = params.get(name);

if (null == param) {

return null;

} else {

return param.get(0);

}

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修改ParentResponse

public class ParentResponse {

//SocketChannel的封装

private ChannelHandlerContext ctx;

private HttpRequest req;

public ParentResponse(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;");

ctx.write(response);

} finally {

ctx.flush();

ctx.close();

}

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修改TomcatStart

public class TomcatStart {

private int port = 8080;

private Map<String, ParentServlet> servletMapping = new HashMap<String, ParentServlet>();

private Properties webProperties = new Properties();

private void init() {

try {

String WEB_INF = this.getClass().getResource("/").getPath();

FileInputStream fis = new FileInputStream(WEB_INF + "web.properties");

webProperties.load(fis);

for (Object k : webProperties.keySet()) {

String key = k.toString();

if (key.endsWith(".url")) {

String servletName = key.replaceAll("\\.url$", "");

String url = webProperties.getProperty(key);

String className = webProperties.getProperty(servletName + ".className");

//单实例多线程

ParentServlet obj = (ParentServlet) Class.forName(className).newInstance();

servletMapping.put(url, obj);

}

} catch (Exception e) {

e.printStackTrace();

}

public void start() {

//1.加载配置类，初始化servletMapping

init();

// Netty NIO Reactor模型 Boss Worker

//Boss 线程

EventLoopGroup bossGroup = new NioEventLoopGroup();

//Work线程

EventLoopGroup workGroup = new NioEventLoopGroup();

ServerBootstrap server = null;

try {

//创建对象

server = new ServerBootstrap();

//配置参数

//链式编程

server.group(bossGroup, workGroup)

//主线程处理类，

.channel(NioServerSocketChannel.class)

//子线程处理类

.childHandler(new ChannelInitializer<SocketChannel>() {

@Override

protected void initChannel(SocketChannel client) throws Exception {

//无锁化串行编程

//netty对http的封装对顺序有要求

//httpResponseEncoder 编码器

client.pipeline().addLast(new HttpResponseEncoder());

//httprequestDecoder 解码器

client.pipeline().addLast(new HttpRequestDecoder());

//业务处理器

client.pipeline().addLast(new TomcatHandler());

}

})

//主线程线程最大数量128

.option(ChannelOption.SO_BACKLOG, 128)

//子线程配置保存长连接

.childOption(ChannelOption.SO_KEEPALIVE, true);

ChannelFuture f = server.bind(port).sync();

System.out.println("Tomcat 已启动，监听端口是：" + this.port);

f.channel().closeFuture().sync();

} catch (Exception e) {

e.printStackTrace();

} finally {

bossGroup.shutdownGracefully();

workGroup.shutdownGracefully();

}

public class TomcatHandler extends ChannelInboundHandlerAdapter {

@Override

public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {

if (msg instanceof HttpRequest) {

System.out.println("hello request");

HttpRequest req = (HttpRequest) msg;

ParentRequest request = new ParentRequest(ctx, req);

ParentResponse response = new ParentResponse(ctx, req);

String url = request.getUrl();

if (servletMapping.containsKey(url)) {

//7.调用实例化对象的service方法

servletMapping.get(url).service(request, response);

} else {

response.write("404 - Not Found");

}

public static void main(String[] args) {

//启动

new TomcatStart().start();

}

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4.访问

http://localhost:8080/first