【发布时间】：2015-04-22 04:08:40
【问题描述】：
这是我们正在上的一门课程的作业，我需要一些帮助。
我遇到问题，例如，尝试请求一个不存在的文件，它会出现一个 404 文件未找到页面，但是当我查看 Safari 的网络工具时，我可以看到响应代码是200，OK，这是定义错误，应该是错误的代码。
但是为什么我看不到，我在发生错误时发送错误代码标题，但它仍然不起作用。有人可以指出我正确的方向，或者只是说问题是什么，我可以解决它：D？
主要：
import java.io.File;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketAddress;
public class WebServer {
private static int PORT = 8888;
private static String ROOT_DIR = "";
public static void main(String[] args) {
if (isCorrect(args) == true) {
boolean isRunning = true;
try {
/* Creates a new server socket */
ServerSocket serverSocket = new ServerSocket();
/* Binds the port to the server */
SocketAddress localBindPoint = new InetSocketAddress(PORT);
serverSocket.bind(localBindPoint);
System.out.println("==============================================" +
"\n| HTTP Web Server |" +
"\n===================" +
"\n| Configuration: " +
"\n| Directory: " +
"\n| " + ROOT_DIR +
"\n| Port: " +
"\n| " + PORT +
"\n| Usage: <directory> <port>" +
"\n| ctrl-c to exit" +
"\n==============================================");
/* The server is running */
while (isRunning) {
try {
/* Accept connection by client */
Socket socket = serverSocket.accept();
/* Each connected client gets a new thread */
new Thread(new RequestHandler(socket, ROOT_DIR)).start();
} catch (IOException e) {
System.err.println(e.getMessage());
}
}
} catch (IOException e) {
System.err.println("Address already in use!" +
"\nClose running connection or choose other port");
}
} else
usageMsg();
System.exit(1);
}
public static boolean isDirectory(String path){
File filePath = null;
try{
filePath = new File(path);
/* False if file is not a directory */
if (!filePath.isDirectory())
return false;
}
catch (Exception e){
System.err.println(e.getMessage());
}
/* Seems to be a file path */
return true;
}
public static boolean isCorrect(String[] args){
if (args.length != 2){
usageMsg();
return false;
}
try{
ROOT_DIR = args[0].toString();
PORT = Integer.parseInt(args[1]);
}
catch (NumberFormatException n){
System.err.println(n.getMessage());
}
if (!isDirectory(ROOT_DIR)){
usageMsg();
return false;
}
return true;
}
public static void usageMsg(){
System.err.println("Invalid arguments"+
"\nUsage: java -jar Webserver.jar <directory> <port>");
}
}
请求处理程序：
import java.io.*;
import java.net.Socket;
import java.util.StringTokenizer;
/**
* Web Server Request Handler.
* Created on 2015-02-16.
*/
public class RequestHandler implements Runnable {
/*
TODO ( ) Problem 1
TODO ( ) Problem 2
TODO ( ) Problem 3
TODO (X) Index page for first page.
TODO (X) Read and download images & other files
TODO ( ) Fix header responses
TODO ( ) Error responses
*/
private String
OK = "HTTP/1.0 200 OK",
NOT_FOUND = "HTTP/1.0 404 Not Found",
BAD_REQUEST = "HTTP/1.0 400 Bad Request",
FORBIDDEN = "HTTP/1.0 403 Forbidden",
SERVER_ERROR = "HTTP/1.0 500 Internal Server Error";
private String ROOT_DIR;
private Socket client;
private PrintStream send;
private DataInputStream fromClient;
private DataOutputStream out;
RequestHandler(Socket client, String ROOT_DIR) {
this.client = client;
this.ROOT_DIR = ROOT_DIR;
try {
send = new PrintStream(client.getOutputStream());
fromClient = new DataInputStream(client.getInputStream());
out = new DataOutputStream(new BufferedOutputStream(client.getOutputStream()));
} catch (IOException e) {
System.err.println(e.getMessage());
}
}
/* Reads the HTTP request and responds */
public void run() {
String request = null;
String fileName = null;
StringTokenizer tok = null;
try {
/* Read HTTP request from client */
while ((request = fromClient.readLine()) != null) {
System.out.println(request);
tok = new StringTokenizer(request);
/* Extracts the file path from the GET command */
if (tok.hasMoreElements() && tok.nextToken().equals("GET")
&& tok.hasMoreElements()) {
fileName = tok.nextToken();
} else
throw new FileNotFoundException();
/* */
if (fileName.endsWith("/"))
fileName += "index.html";
/* Illegal characters, prevent access to super directories */
if (fileName.indexOf("..") >= 0 || fileName.indexOf('|') >= 0
|| fileName.indexOf(':') >= 0 || fileName.indexOf('~') >= 0) {
error(FORBIDDEN, "Forbidden Access", fileName);
}
else
if (new File(fileName).isDirectory()) {
fileName = fileName.replace('\\', '/');
send.close();
return;
}
/* File name is ROOT_DIR + file name */
fileName = ROOT_DIR + fileName;
/* Create file */
File file = new File(fileName);
if (file.isDirectory()) {
fileName = fileName + "index.html";
}
/* File does not exist */
if (file.exists()){
/* Determines the MIME type of the file */
String mimeType = getMimeType(file);
/* Sends the file */
sendFile(file, mimeType, fileName);
client.close();
}
else
error(NOT_FOUND, "404 File Not Found", fileName);
}
}
catch (FileNotFoundException e) {
System.err.println(e.getMessage());
}
catch (IOException e){
System.err.println(e.getMessage());
}
}
/* Sends the requested file to the client */
public void sendFile(File file, String fileType, String fileName) {
try {
// Buffer must not be to low, => fragments
int length = (int) file.length();
FileInputStream fileIn = new FileInputStream(fileName);
byte[] bytes = new byte[length];
/* Write until bytes is empty */
while ((length = fileIn.read(bytes)) != -1 ){
out.write(bytes, 0, length);
out.flush();
out.writeBytes(OK);
out.writeBytes("Server: Jakobs Web Server v1.0");
out.writeBytes("Content-Type: " + fileType + "\r\n");
out.writeBytes("Content-Length: " + length + "\r\n");
out.writeBytes("");
}
send.close();
} catch (IOException e) {
System.err.println(e.getMessage());
}
}
/* Sends the header response to the client */
public void sendHeaderResponse(String code, String fileType){
try {
out.writeBytes(code);
out.writeBytes("Server: Jakobs Web Server v1.0");
out.writeBytes("Content-Type: " + fileType + "\r\n");
out.writeBytes("");
}
catch (IOException e){
System.err.println(e.getMessage());
}
}
/* Sends error response to the client */
public void error(String code, String error, String fileName){
System.err.println(error +
"\nFile Requested: " + fileName);
/* Sends the error code header */
sendHeaderResponse(code, fileName);
/* Sends the error message and cause to client */
send.print("<html><head><title>" + error + "</title></head><body>");
send.print("<h1>" + error + "</h1>\r\n");
send.println("Location: /" + fileName + "/\r\n");
send.println("Exception Cause: " + error + "\r\n");
send.print("<a href=\"index.html\">Start Page</a>");
send.print("</body>\"</html>");
send.flush();
send.close();
}
/* Finds out the MIME type of the requested file */
public String getMimeType(File f) {
String file = f.toString();
String type = "";
if (file.endsWith(".txt")) {
type = "text/txt";
} else if (file.endsWith(".html") || file.endsWith("htm")) {
type = "text/html";
} else if (file.endsWith(".jpg")) {
type = "image/jpg";
} else if (file.endsWith(".png")) {
type = "image/png";
} else if (file.endsWith(".jpeg")) {
type = "image/jpeg";
} else if (file.endsWith(".gif")) {
type = "image/gif";
} else if (file.endsWith(".pdf")) {
type = "application/pdf";
} else if (file.endsWith(".mp3")) {
type = "audio/mpeg";
} else if (file.endsWith(".class")){
type = "application/octet-stream";
} else if (file.endsWith(".mp4")){
type = "video/mp4";
}
return type;
}
}
【问题讨论】：