我正在使用套接字编程在 java 中实现 HTTP 1 协议。我得到了输出，但是在听取了一个请求后，服务器给出了如下错误
null
java.lang.NullPointerException
at httpRequest.processRequest(httpRequest.java:24)
at httpRequest.run(httpRequest.java:119)
at java.lang.Thread.run(Unknown Source)
这是我的 eclipse 输出的副本
Waiting for connection
Connection Established
Waiting for connection
Connection Established
Waiting for connection
GET / HTTP/1.1
Host: localhost:5358
Connection: keep-alive
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.76 Safari/537.36
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
null
java.lang.NullPointerException
这是我的源代码。
import java.net.*;
import java.io.*;
import java.util.*;
public final class webServer
{
public static void main(String arg[]) throws Exception
{
int port=5358;
ServerSocket listen = new ServerSocket(port);
while(true)
{
System.out.println("Waiting for connection\n\n");
Socket server = listen.accept();
System.out.println("Connection Established\n\n");
httpRequest request = new httpRequest(server);
Thread thread = new Thread(request);
thread.start();
}
}
}
class httpRequest implements Runnable
{
final String CRLF = "\r\n";
Socket socket;
public httpRequest(Socket socket) throws Exception
{
this.socket = socket;
}
public void processRequest() throws Exception
{
InputStream is = socket.getInputStream();
DataOutputStream os = new DataOutputStream(socket.getOutputStream());
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String requestLine = br.readLine();
System.out.println("\n\n\n" + requestLine);
String headerLine = null;
while ((headerLine = br.readLine()).length() != 0)
{
System.out.println(headerLine);
}
StringTokenizer tokens = new StringTokenizer(requestLine);
tokens.nextToken(); // skip over the method, which should be "GET"
String fileName = tokens.nextToken();
// Prepend a "." so that file request is within the current directory.
fileName = "." + fileName;
FileInputStream fis = null;
boolean fileExists = true;
try
{
fis = new FileInputStream(fileName);
}
catch (FileNotFoundException e)
{
fileExists = false;
}
String statusLine = null;
String contentTypeLine = null;
String entityBody = null;
if (fileExists)
{
statusLine = "HTTP/1.0 200 OK" + CRLF ;
contentTypeLine = "Content-type: " + contentType( fileName ) + CRLF;
}
else
{
statusLine = "HTTP/1.0 404 Not Found" + CRLF;
contentTypeLine = "Content-type: " + "text/html" + CRLF;
entityBody = "<HTML>" +
"<HEAD><TITLE>Not Found</TITLE></HEAD>" +
"<BODY>Not Found</BODY></HTML>";
}
// os.close();
//br.close();
//socket.close();
// Send the status line.
os.writeBytes(statusLine);
// Send the content-type line.
os.writeBytes(contentTypeLine);
// Send a blank line to indicate the end of the header lines.
os.writeBytes(CRLF);
if (fileExists) {
sendBytes(fis, os);
fis.close();
} else {
os.writeBytes(entityBody);
}
}
private void sendBytes(FileInputStream fis, DataOutputStream os) throws Exception {
byte[] buffer = new byte[1024];
int bytes = 0;
// Copy requested file into the socket's output stream.
while((bytes = fis.read(buffer)) != -1 ) {
os.write(buffer, 0, bytes);
}
}
private String contentType(String fileName)
{
if (fileName.endsWith(".htm") || fileName.endsWith(".html"))
{
return "text/html";
}
if (fileName.endsWith(".jpg") || fileName.endsWith(".jpeg"))
{
return "image/jpeg";
}
if (fileName.endsWith(".gif"))
{
return "image/gif";
}
if (fileName.endsWith(".txt"))
{
return "text/plain";
}
if (fileName.endsWith(".pdf"))
{
return "application/pdf";
}
return "application/octet-stream";
}
public void run()
{
try
{
processRequest();
}
catch (Exception e)
{
System.out.println(e);
}
}
}