我找到了here以下的Web服务器类。我需要编写一个可以从此服务器检索文件的Android应用程序（客户端）。如果有人能够帮助我做到这一点会很棒。谢谢。
服务器主机地址为：My-PC / ipaddress
当我执行客户端时，它会给出异常。
java.net.ConnectException：拒绝连接：连接
WebServer.Java
import java.io.*;
import java.net.*;
public class WebServer extends Thread {
public WebServer() {
this.start();
}
private void displayString(String string) { //an alias to avoid typing so much!
System.out.println(string);
}
private static final int UMBRA_PORT = 30480;
private static final int ROOM_THROTTLE = 200;
private InetAddress hostAddress;
//this is a overridden method from the Thread class we extended from
public void run() {
//we are now inside our own thread separated from the gui.
ServerSocket serversocket = null;
//To easily pick up lots of girls, change this to your name!!!
displayString("The simple httpserver v. 0000000000\nCoded by Jon Berg" +
"<jon.berg[on server]turtlemeat.com>\n\n");
//Pay attention, this is where things starts to cook!
try {
//print/send message to the guiwindow
displayString("Trying to bind to localhost on port " + Integer.toString(UMBRA_PORT) + "...");
//make a ServerSocket and bind it to given port,
//serversocket = new ServerSocket(port);
}
catch (Exception e) { //catch any errors and print errors to gui
displayString("\nFatal Error:" + e.getMessage());
return;
}
// Attempt to get the host address
try
{
hostAddress = InetAddress.getLocalHost();
}
catch(UnknownHostException e)
{
System.out.println("Could not get the host address.");
return;
}
// Announce the host address
System.out.println("Server host address is: "+hostAddress);
// Attempt to create server socket
try
{
serversocket = new ServerSocket(UMBRA_PORT,0,hostAddress);
}
catch(IOException e)
{
System.out.println("Could not open server socket.");
return;
}
// Announce the socket creation
System.out.println("Socket "+serversocket+" created.");
displayString("OK!\n");
//go in a infinite loop, wait for connections, process request, send response
while (true) {
displayString("\nReady, Waiting for requests...\n");
try {
//this call waits/blocks until someone connects to the port we
//are listening to
Socket connectionsocket = serversocket.accept();
//figure out what ipaddress the client commes from, just for show!
InetAddress client = connectionsocket.getInetAddress();
//and print it to gui
displayString(client.getHostName() + " connected to server.\n");
//Read the http request from the client from the socket interface
//into a buffer.
BufferedReader input =
new BufferedReader(new InputStreamReader(connectionsocket.
getInputStream()));
//Prepare a outputstream from us to the client,
//this will be used sending back our response
//(header + requested file) to the client.
DataOutputStream output =
new DataOutputStream(connectionsocket.getOutputStream());
//as the name suggest this method handles the http request, see further down.
//abstraction rules
http_handler(input, output);
}
catch (Exception e) { //catch any errors, and print them
displayString("\nError:" + e.getMessage());
}
} //go back in loop, wait for next request
}
//our implementation of the hypertext transfer protocol
//its very basic and stripped down
private void http_handler(BufferedReader input, DataOutputStream output) {
int method = 0; //1 get, 2 head, 0 not supported
String http = new String(); //a bunch of strings to hold
String path = new String(); //the various things, what http v, what path,
String file = new String(); //what file
String user_agent = new String(); //what user_agent
try {
//This is the two types of request we can handle
//GET /index.html HTTP/1.0
//HEAD /index.html HTTP/1.0
String tmp = input.readLine(); //read from the stream
String tmp2 = new String(tmp);
tmp.toUpperCase(); //convert it to uppercase
if (tmp.startsWith("GET")) { //compare it is it GET
method = 1;
} //if we set it to method 1
if (tmp.startsWith("HEAD")) { //same here is it HEAD
method = 2;
} //set method to 2
if (method == 0) { // not supported
try {
output.writeBytes(construct_http_header(501, 0));
output.close();
return;
}
catch (Exception e3) { //if some error happened catch it
displayString("error:" + e3.getMessage());
} //and display error
}
//}
//tmp contains "GET /index.html HTTP/1.0 ......."
//find first space
//find next space
//copy whats between minus slash, then you get "index.html"
//it's a bit of dirty code, but bear with me...
int start = 0;
int end = 0;
for (int a = 0; a < tmp2.length(); a++) {
if (tmp2.charAt(a) == ' ' && start != 0) {
end = a;
break;
}
if (tmp2.charAt(a) == ' ' && start == 0) {
start = a;
}
}
path = tmp2.substring(start + 2, end); //fill in the path
}
catch (Exception e) {
displayString("errorr" + e.getMessage());
} //catch any exception
//path do now have the filename to what to the file it wants to open
displayString("\nClient requested:" + new File(path).getAbsolutePath() + "\n");
FileInputStream requestedfile = null;
try {
//try to open the file,
requestedfile = new FileInputStream(path);
}
catch (Exception e) {
try {
//if you could not open the file send a 404
output.writeBytes(construct_http_header(404, 0));
//close the stream
output.close();
}
catch (Exception e2) {}
displayString("error" + e.getMessage());
} //print error to gui
//happy day scenario
try {
int type_is = 0;
//find out what the filename ends with,
//so you can construct a the right content type
if (path.endsWith(".zip") ) {
type_is = 3;
}
if (path.endsWith(".jpg") || path.endsWith(".jpeg")) {
type_is = 1;
}
if (path.endsWith(".gif")) {
type_is = 2;
}
if (path.endsWith(".ico")) {
type_is = 4;
}
if (path.endsWith(".xml")) {
type_is = 5;
}
//write out the header, 200 ->everything is ok we are all happy.
output.writeBytes(construct_http_header(200, 5));
//if it was a HEAD request, we don't print any BODY
if (method == 1) { //1 is GET 2 is head and skips the body
byte [] buffer = new byte[1024];
while (true) {
//read the file from filestream, and print out through the
//client-outputstream on a byte per byte base.
int b = requestedfile.read(buffer, 0,1024);
if (b == -1) {
break; //end of file
}
output.write(buffer,0,b);
}
//clean up the files, close open handles
}
output.close();
requestedfile.close();
}
catch (Exception e) {}
}
//this method makes the HTTP header for the response
//the headers job is to tell the browser the result of the request
//among if it was successful or not.
private String construct_http_header(int return_code, int file_type) {
String s = "HTTP/1.0 ";
//you probably have seen these if you have been surfing the web a while
switch (return_code) {
case 200:
s = s + "200 OK";
break;
case 400:
s = s + "400 Bad Request";
break;
case 403:
s = s + "403 Forbidden";
break;
case 404:
s = s + "404 Not Found";
break;
case 500:
s = s + "500 Internal Server Error";
break;
case 501:
s = s + "501 Not Implemented";
break;
}
s = s + "\r\n"; //other header fields,
s = s + "Connection: close\r\n"; //we can't handle persistent connections
s = s + "Server: SimpleHTTPtutorial v0\r\n"; //server name
switch (file_type) {
//plenty of types for you to fill in
case 0:
break;
case 1:
s = s + "Content-Type: image/jpeg\r\n";
break;
case 2:
s = s + "Content-Type: image/gif\r\n";
break;
case 3:
s = s + "Content-Type: application/x-zip-compressed\r\n";
break;
case 4:
s = s + "Content-Type: image/x-icon\r\n";
case 5:
s = s + "Content-Type: text/xml\r\n";
break;
default:
s = s + "Content-Type: text/html\r\n";
break;
}
////so on and so on......
s = s + "\r\n"; //this marks the end of the httpheader
//and the start of the body
//ok return our newly created header!
return s;
}
}
Client.Java
public class WatchMeManagerClient {
private static Socket socket;
private static PrintWriter printWriter;
public static void main(String[] args) throws Exception {
try {
URL url;
URLConnection urlConn;
DataInputStream dis;
url = new URL("http://ipaddress/xml/userGroup.xml");
urlConn = url.openConnection();
urlConn.setDoInput(true);
urlConn.setUseCaches(false);
dis = new DataInputStream(urlConn.getInputStream());
String s;
while ((s = dis.readLine()) != null) {
System.out.println(s);
}
dis.close();
}
catch (MalformedURLException mue) {
System.out.println(mue.toString());
} catch (IOException ioe) {
System.out.println(ioe.toString());
}
}
}
当我在PC上运行代码时，它可以工作。但是当我尝试在Android设备上执行它时会出现以下错误。
答案 0 :(得分：1)
此类问题可能是由于以下原因之一：
端口错误
防火墙正在阻止它。
答案 1 :(得分：0)
使用套接字需要以下权限，我认为您缺少这些权限：
<uses-permission android:name="android.permission.INTERNET" />
答案 2 :(得分：0)
您是否允许在清单中访问互联网？
<uses-permission android:name="android.permission.INTERNET"/>