The simplest http server, the source code can be downloaded: http://download.csdn.net/detail/ajaxhu/6356885
Let’s briefly introduce the principle. The browser opens a web page can be simply divided into 3 stages:
1. Send a request string in a certain format to the server through the socket (which contains the URL entered by the user), such as:
| Accept | text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 |
| Accept-Encoding | gzip, deflate |
| Accept-Language | zh-cn,zh;q=0.8,en-us;q=0.5,en;q=0.3 |
| Connection | keep-alive |
| Host | localhost:8001 |
| User-Agent | Mozilla/5.0 (Windows NT 6.1; rv:22.0) Gecko/20100101 Firefox/22.0 |
2. The server receives the request string from the browser and parses out the URL requested by the user. The URL actually corresponds to the file in the server.
For example, http:\\www.demo.com actually corresponds to http:\\www.demo.com\index.html in the server. The server will read the index.html file into the byte array and add the header information (also string), returned to the browser that sent the request.
3. The browser receives the byte stream returned by the server, and judges the original data type of the returned byte array (web page, picture, other) according to the returned header information. For example, the returned header information is as follows:
| Content-Type | text/html |
Note that the returned byte array is originally an html page, and the browser will parse the html page and display the data.
If the header information returned by the server is as follows:
| Content-Type | image/jpeg |
The source code is given below:
Note: 1. To run the program, you need to create a new webapp folder in the same directory, and put the website you want to run into (temporarily only support html, jpg, gif, png)
2. Program running parameters: It can be run without parameters, and it is bound to port 80 by default, which may conflict. You can add a parameter to set the port, for example: java -jar MyHtmlServer.jar 8001
8001 is the bound port number.
3. After running the program, enter http://localhost:port number/resource path in the browser. For example, the port 8001 is bound, and there is an index.html file in the webapp folder. Now you need to access this file. Enter: http://localhost:8001/index.html in the browser to access. If it is bound to port 80, you can directly write: http://localhost/index.html, the browser uses 80 as the server port by default.
Source code:
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.InterruptedIOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class MyHtmlServer {
public static void main(String[] args) throws IOException {
int port=80;
if(args.length>0)
port=Integer.valueOf(args[0]);
new MyHtmlServer().start(port);
}
/**
* Start the http server on the specified port
* @param port specified port
* @throws IOException
*/
public void start(int port) throws IOException {
ServerSocket server = new ServerSocket(port);
System.out.println("server start at "+port+"...........");
while (true) {
Socket client = server.accept();
ServerThread serverthread = new ServerThread(client);
serverthread.start();
}
}
/**
* The server responds to the thread, which starts a ServerThread thread every time a browser request is received
* @author
*
*/
class ServerThread extends Thread {
Socket client;
public ServerThread(Socket client) {
this.client = client;
}
/**
* Read the file content and convert it into a byte array
* @param filename filename
* @return
* @throws IOException
*/
public byte[] getFileByte(String filename) throws IOException
{
ByteArrayOutputStream baos=new ByteArrayOutputStream();
File file=new File(filename);
FileInputStream fis=new FileInputStream(file);
byte[] b=new byte[1000];
int read;
while((read=fis.read(b))!=-1)
{
baos.write(b,0,read);
}
fis.close();
baos.close();
return baos.toByteArray();
}
/**
* Analyze the url in the http request, analyze the resources requested by the user, and normalize the request url
* For example, the request "/" should be standardized as "/index.html", and "/index" should be standardized as "/index.html"
* @param queryurl user's original url
* @return the normalized url, which is the path for the user to request the resource
*/
private String getQueryResource(String queryurl)
{
String queryresource=null;
int index=queryurl.indexOf('?');
if(index!=-1)
{
queryresource=queryurl.substring(0,queryurl.indexOf('?'));
}
else
queryresource=queryurl;
index=queryresource.lastIndexOf("/");
if(index+1==queryresource.length())
{
queryresource=queryresource+"index.html";
}
else
{
String filename=queryresource.substring(index+1);
if(!filename.contains("."))
queryresource=queryresource+".html";
}
return queryresource;
}
/**
* According to the resource type requested by the user, set the information of the http response header, mainly to determine the file type (html, jpg...) requested by the user
* @param queryresource
* @return
*/
private String getHead(String queryresource)
{
String filename="";
int index=queryresource.lastIndexOf("/");
filename=queryresource.substring(index+1);
String[] filetypes=filename.split("\\.");
String filetype=filetypes[filetypes.length-1];
if(filetype.equals("html"))
{
return "HTTP/1.0200OK\n"+"Content-Type:text/html\n" + "Server:myserver\n" + "\n";
}
else if(filetype.equals("jpg")||filetype.equals("gif")||filetype.equals("png"))
{
return "HTTP/1.0200OK\n"+"Content-Type:image/jpeg\n" + "Server:myserver\n" + "\n";
}
else return null;
}
@Override
public void run() {
InputStream is;
try {
is = client.getInputStream();
BufferedReader br = new BufferedReader(
new InputStreamReader(is));
int readint;
char c;
byte[] buf = new byte[1000];
OutputStream os = client.getOutputStream();
client.setSoTimeout(50);
byte[] data = null;
String cmd = "";
String queryurl = "";
int state = 0;
String queryresource;
String head;
while (true) {
readint = is.read();
c = (char) readint;
boolean space=Character.isWhitespace(readint);
switch (state) {
case 0:
if (space)
continue;
state = 1;
case 1:
if (space) {
state=2;
continue;
}
cmd+=c;
continue;
case 2:
if(space)
continue;
state=3;
case 3:
if(space)
break;
queryurl+=c;
continue;
}
break;
}
queryresource=getQueryResource(queryurl);
head=getHead(queryresource);
while (true) {
try {
if ((readint = is.read(buf)) > 0) {
// System.out.write(buf);
} else if (readint < 0)
break;
} catch (InterruptedIOException e) {
data = getFileByte("webapp"+queryresource);
}
if (data != null) {
os.write(head.getBytes("utf-8"));
os.write(data);
os.close();
break;
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace ();
}
}
}
}