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Я пытаюсь создать небольшой веб-сервер и иметь возможность генерировать сообщения ответа HTTP 200, 301, и 404.генерирующих Http 301 Ответное сообщение
Я могу получить 200 и 404, чтобы работать, но У меня возникли проблемы с 301.
Когда я пытаюсь получить доступ к странице, которая «постоянно перемещена», мой браузер не перенаправляется, и я получаю java.lang.NullPointerException из java.
Способ, которым он определяется, если код должен быть 301, он проверяет список строк для файла, к которому клиент пытается получить доступ, и если исходный файл, к которому они пытались получить доступ, был перемещен, он будет в списке, а также его новое имя/местоположение. Поэтому, если исходный файл «index5.html» и он был перенесен в «index.html», то они будут в массиве, а «index5.html» будет иметь индекс 1 до «index.html»
Я также просто тестируем на своей машине, так что я буду использовать Localhost для URL и использует порт 9012.
Вот мой код:
import java.io.*;
import java.net.*;
import java.util.*;
public final class HttpRequest implements Runnable {
final static String CarrLine = "\r\n";
Socket clientSocket;
// A list of files that have been moved.
// Even indexes (0, 2, 4, ...) are the original file names.
// Odd indexes (1, 3, 5, ...) are where the files of previous indexes moved to.
static String movedFiles[] = {"index5.html", "index.html", "page.html", "homepage.html"};
// This sets the Httprequest object socket equal to
// the socket the client comes in through
public HttpRequest(Socket socket) throws Exception {
this.clientSocket = socket;
}
// Here we define a new method that overwrites the
// previous method in the Runnables class. This is done
// so that when an Http request is attempted, and
// something goes wrong, our whole web server will
// not fail and crash.
@Override
public void run(){
try {
// This is where the method to actually start the Http request starts.
requestProcessing();
} catch (Exception ex) { System.out.print(ex); }
}
// This is our main processing method to take in out Http request
// and spit out a reponse header along with the requested data,
// if there is any.
void requestProcessing() throws Exception {
Boolean fileExists = false;
String CarrLine = "\r\n";
String statusCode = null;
String responseHeader = "HTTP/1.1 ";
String fileName, line = null;
String clientSentence = null;
ArrayList<String> records = new ArrayList<String>();
FileInputStream requestedFileStream = null;
File requestedFile;
// Starts input from client and establishes filters
BufferedReader inFromClient = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
// Starts output stream for output to client through socket
DataOutputStream outToClient = new DataOutputStream(clientSocket.getOutputStream());
/*
// Reads in GET from client BufferedReader
while ((line = inFromClient.readLine()) != null){
records.add(line);
break;
}*/
clientSentence = inFromClient.readLine();
// Parses and stores file name the client wants in a string
fileName = parseGET(clientSentence);
if (!existingFile(fileName)){
// Here is where the 301 response message is generated and
// retrieve the correct filename.
if (hasMoved(fileName) != -1){
statusCode = "301";
responseHeader = responseHeader + statusCode + " Moved Permanently\n";
responseHeader = responseHeader + "Location: localhost:9012/"
+ movedFiles[hasMoved(fileName)] + CarrLine;
}
// This generates the response header for the client
// if the file the client is looking for is not there (404).
else {
statusCode = "404";
responseHeader = responseHeader + statusCode + " Not Found: \n";
responseHeader = responseHeader + "Content-Type: text/html" + CarrLine;
}
}
// This generates the 200 status code response header
// to send to the client saying the file was found.
if (existingFile(fileName)) {
statusCode = "200";
responseHeader = responseHeader + statusCode + " OK: \n";
responseHeader = responseHeader + "Content-Type: " + fileType(fileName) + CarrLine;
requestedFileStream = openFileStream(fileName);
}
// Outputs the response message to the client through a data stream
outToClient.writeBytes(responseHeader);
outToClient.writeBytes(CarrLine);
// If the file the client is requesting exists,
// begin writing file out to client.
if (existingFile(fileName)){
fileWriteOut(requestedFileStream, outToClient);
requestedFileStream.close();
}
else if(hasMoved(fileName) != -1){
outToClient.writeBytes("File Moved");
}
// If the file the client is requesting does not exist,
// return a 404 message.
else {
outToClient.writeBytes("404: File not found!");
}
// Closes all open streams and sockets to the client.
inFromClient.close();
outToClient.close();
clientSocket.close();
}
// This parses the GET line from the client to get the filename the client is requesting
String parseGET(String clientString){
String temp[] = clientString.split(" /");
temp = temp[1].split(" ");
return temp[0];
}
// This is used to find the file the client is requesting.
// It will return null if no file was found/opened.
FileInputStream openFileStream(String file){
FileInputStream fileStream = null;
// Opening the file stream is in a try catch statment so that
// incase there was no file, the program doesn't crash
// and it'll alert the user on the console.
try {
fileStream = new FileInputStream(file);
} catch (FileNotFoundException e) {
System.out.println(e);
return null;
}
return fileStream;
}
// Determines the file type that is being sent to the client
// and returns the appropriate string
String fileType(String clientRequestFile){
// If the file ends in .html or .htm, it will return "text/html"
// so that it can be added to the response message.
if (clientRequestFile.endsWith(".html") || clientRequestFile.endsWith(".htm")){
return "text/html";
}
// If the file ends in .jpg, it will return "text/jpeg"
// so that it can be added to the response message.
if (clientRequestFile.endsWith(".jpg")){
return "text/jpg";
}
// If the file ends in .css, it will return "text/css"
// so that it can be added to the response message.
if (clientRequestFile.endsWith(".css")){
return "text/css";
}
// Returns this by default, if none of the above.
return "application/octet-stream";
}
// This creates a 2k buffer and writes out
// requested filed to the client.
static void fileWriteOut(FileInputStream clientStream, OutputStream toClient) throws Exception{
byte[] buffer = new byte[2048];
int bytes = 0;
while ((bytes = clientStream.read(buffer)) != -1){
toClient.write(buffer, 0, bytes);
}
}
// This determines whether or not a file that
// the client has requested exists or not.
// Returns a Boolean value.
static Boolean existingFile(String fileName){
File file = new File(fileName);
if (file.exists() && !file.isDirectory()){
return true;
}
return false;
}
// Determines if a file has been moved and if so,
// returns the index of the NEW file. Else it
// returns -1.
static int hasMoved(String fileName){
int i = 0;
for (i = 0; i < movedFiles.length; i=i+2){
if (movedFiles[i].equals(fileName)){
return i+1;
}
}
return -1;
}
}
Может кто-то мне точку в правильном направлении делаете это правильно?
Спасибо!