A simple Java Web server implementation

A simple Java Web server implementation, relatively simple, based on java.net.Socket and java.net.ServerSocket implementation;

Program execution steps

2. Create a ServerSocket object;
4. Call the Accept method of the ServerSocket object, wait for the connection, the successful connection will return a socket object, otherwise blocking the wait;
6. Gets the InputStream and outputstream byte streams from the socket object that correspond to request requests and response responses respectively;
8. processing request: Reading inputstream byte stream information, turn into a string form, and parse, here the resolution is relatively simple, just get Uri ) information;
10. Processing response: Based on the parsed URI information, look for the requested resource resource file from the Web_root directory, read the resource file, and write it to the outputstream byte stream ;
12. Close the socket object;
14. Go to step 2 and continue waiting for the connection request;

Code implementation

Server implementation:

 PackageEx01.pyrmont;ImportJava.net.Socket;ImportJava.net.ServerSocket;Importjava.net.InetAddress;ImportJava.io.InputStream;ImportJava.io.OutputStream;Importjava.io.IOException;ImportJava.io.File; Public classHttpserver {/*** Web_root is the directory where HTML and other files are stored. Web_root here is the Webroot directory under the working directory*/     Public Static FinalString web_root = System.getproperty ("User.dir") + File.separator + "Webroot"; //Close Service Command    Private Static FinalString Shutdown_command = "/shutdown";  Public Static voidMain (string[] args) {httpserver server=NewHttpserver (); //Wait for connection requestserver.await (); }     Public voidawait () {ServerSocket ServerSocket=NULL; intPort = 8080; Try {            //Server Socket ObjectServerSocket =NewServerSocket (port, 1, Inetaddress.getbyname ("127.0.0.1")); } Catch(IOException e) {e.printstacktrace (); System.exit (1); }        //Loop waits for a request         while(true) {Socket Socket=NULL; InputStream input=NULL; OutputStream Output=NULL; Try {                //wait for connection, after successful connection, return a socket objectSocket =serversocket.accept (); Input=Socket.getinputstream (); Output=Socket.getoutputstream (); //create a Request object and parseRequest Request =NewRequest (input);                Request.parse (); //Check whether the service command is closed                if(Request.geturi (). Equals (Shutdown_command)) { Break; }                //Create a Response objectResponse Response =NewResponse (output);                Response.setrequest (Request);                Response.sendstaticresource (); //close the Socket objectSocket.close (); } Catch(Exception e) {e.printstacktrace (); Continue; }        }    }}

Request class:

 PackageEx01.pyrmont;ImportJava.io.InputStream;Importjava.io.IOException; Public classRequest {PrivateInputStream input; PrivateString URI;  PublicRequest (InputStream input) { This. Input =input; }    //read the request information from the InputStream and get the URI value from the request     Public voidParse () {StringBuffer request=NewStringBuffer (2048); inti; byte[] buffer =New byte[2048]; Try{i=input.read (buffer); } Catch(IOException e) {e.printstacktrace (); I=-1; }         for(intj = 0; J < I; J + +) {request.append (Char) buffer[j]);        } System.out.print (Request.tostring ()); URI=Parseuri (request.tostring ()); }    /*** * requeststring form as follows: * get/index.html http/1.1 * host:localhost:8080 * Connection:keep-aliv E * cache-control:max-age=0 * ... * This function is intended to get the/index.html string*/    Privatestring Parseuri (String requeststring) {intindex1, Index2; Index1= Requeststring.indexof (' '); if(Index1! =-1) {Index2= Requeststring.indexof (", Index1 + 1); if(Index2 >index1)returnRequeststring.substring (index1 + 1, INDEX2); }        return NULL; }     PublicString GetURI () {returnURI; }}

Response class:

 PackageEx01.pyrmont;ImportJava.io.OutputStream;Importjava.io.IOException;ImportJava.io.FileInputStream;ImportJava.io.File;/*HTTP Response = Status-line * ((general-header | response-header | entity-header) CRLF) CRLF [Message-bod Y] status-line = http-version sp status-code sp reason-phrase CRLF*/ Public classResponse {Private Static Final intBuffer_size = 1024;    Request request;    OutputStream output;  PublicResponse (OutputStream output) { This. Output =output; }     Public voidsetrequest (Request request) { This. Request =request; }     Public voidSendstaticresource ()throwsIOException {byte[] bytes =New byte[Buffer_size]; FileInputStream FIS=NULL; Try {            //writes a web file to the OutputStream byte streamFile File =NewFile (Httpserver.web_root, Request.geturi ()); if(File.exists ()) {FIS=Newfileinputstream (file); intch = fis.read (Bytes, 0, buffer_size);  while(ch! =-1) {output.write (bytes,0, CH); CH= Fis.read (Bytes, 0, buffer_size); }            } Else {                //File not foundString errormessage = "http/1.1 404 File Not found\r\n" + "content-type:text/html\r\n" + "content- length:23\r\n "+" \ r \ n "+" ;            Output.write (Errormessage.getbytes ()); }        } Catch(Exception e) {//thrown if cannot instantiate a File objectSystem.out.println (e.tostring ()); } finally {            if(FIS! =NULL) Fis.close (); }    }}

Results test

Access the existing resource files (note the Webroot folder in the project directory):

To access a resource file that does not exist:

To shut down the server:

Reference: Deep analysis of Tomcat

A simple Java Web server implementation