走进tomcat之一个简单Web服务器

来源：互联网发布：马歇尔计划知乎编辑：程序博客网时间：2024/05/16 08:18

HTTP(超文本传输协议)允许Web服务器和浏览器通过Internet发送并接收数据，是一种基于“请求-响应”的协议。HTTP使用可靠的TCP链接，TCP协议默认端口为80端口；
Java中Socket类实现了TCP协议，使用Socket进行编写简易Web服务器:包含类（request，response，HttpServer）

Rquest类 :

public class Request {

private InputStream input;

private String uri;

public Request(InputStream input) {

this.input = input;

}

//接收请求

public void parse() {

StringBuffer request = new StringBuffer();

int i;

byte[] buffer = new byte[2048];

try {

i = input.read(buffer);

} catch (Exception e) {

i = -1;

}

for (int j = 0; j < i; j++) {

request.append((char) buffer[j]);

}

System.out.println(request.toString());

uri = parse(request.toString());//解析请求

}

//解析请求

private String parse(String requestString) {

int index1, index2;

index1 = requestString.indexOf(' ');

if (index1 != -1) {

index2 = requestString.indexOf(' ', index1 + 1);

if (index2 > index1) {

return requestString.substring(index1 + 1, index2);

}

return null;

}

public String getUri() {

return uri;

}

}

Reponse 类

public class Response {

private static final int BUFFER_SIZE = 1024;

Request request;

OutputStream output;

public Response(OutputStream output) {

this.output = output;

}

public void serRequest(Request request) {

this.request = request;

}

public void sendStaticResource() throws IOException {

byte[] bytes = new byte[BUFFER_SIZE];

FileInputStream fis = null;

try {

File file = new File(HttpServer1.WEB_ROOT, request.getUri());

if (file.exists()) {

fis = new FileInputStream(file);

int ch = fis.read(bytes, 0, BUFFER_SIZE);

while (ch != -1) {

output.write(bytes, 0, ch);

ch = fis.read(bytes, 0, BUFFER_SIZE);

}

} else {

String errorMessage = "HTTP/1.1 404 File Not Found\r\n" + "Content-Type:text/html\r\n"

+ "Content-length:23\r\n" + "\r\n<h1>404 File Not Found</h1>";

output.write(errorMessage.getBytes());

}

} catch (Exception e) {

System.out.println(e.toString());

} finally {

if (fis != null) {

fis.close();

}

HttpServer类

public class HttpServer1 {

// public static final String WEB_ROOT = System.getProperty("user.der") +

// File.separator + "webroot";

public static final String WEB_ROOT = new File("").getAbsolutePath() + File.separator + "webroot";

private static final String SHUDOWN_COMMAND = "/SHUTDOWN";

private boolean shutdown = false;

public void await() {

ServerSocket serverSocket = null;

int port = 8080;

try {

serverSocket = new ServerSocket(port);

} catch (Exception e) {

e.printStackTrace();

}

while (!shutdown) {

Socket socket = null;

InputStream input = null;

OutputStream output = null;

try {

socket = serverSocket.accept();// 等待请求,返回socket实例

input = socket.getInputStream();

output = socket.getOutputStream();

Request request = new Request(input);

request.parse();

Response response = new Response(output);

response.serRequest(request);

response.sendStaticResource();

socket.close();

shutdown = request.getUri().equals(SHUDOWN_COMMAND);

} catch (Exception e) {

e.printStackTrace();

continue;

}

public static void main(String[] args) {

HttpServer server = new HttpServer();

server.await();

}

静态页面，在工程目录下新建一个webroot文件夹，并新建index.html文件

<!DOCTYPE html>

<html>

<head>

<title>Insert title here</title>

</head>

<body>

<h1>Hello Tomcat</h1>

<h2>走近Tomcat之一个简单Web服务器</h2>

</body>

</html>

运行HttpServer：
在浏览器输入 localhost:8080/index.html
控制台输出:

GET /index.html HTTP/1.1

Host: localhost:8080

Connection: keep-alive

Cache-Control: max-age=0

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8

Upgrade-Insecure-Requests: 1

User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.110 Safari/537.36

DNT: 1

Accept-Encoding: gzip, deflate, sdch

Accept-Language: zh-CN,zh;q=0.8,en-US;q=0.6,en;q=0.4

输入：http://localhost:8080/other.html

控制台内容

GET /other.html HTTP/1.1
Host: localhost:8080
Connection: keep-alive
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.110 Safari/537.36
DNT: 1
Accept-Encoding: gzip, deflate, sdch
Accept-Language: zh-CN,zh;q=0.8,en-US;q=0.6,en;q=0.4

输入localhost:8080/SHUTDOWN
控制台输出

GET /SHUTDOWN HTTP/1.1

Host: localhost:8080

Connection: keep-alive

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8

Upgrade-Insecure-Requests: 1

User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.110 Safari/537.36

DNT: 1

Accept-Encoding: gzip, deflate, sdch

Accept-Language: zh-CN,zh;q=0.8,en-US;q=0.6,en;q=0.4

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