这是一个简单的联网信息服务代码，向服务器传送信息并获取服务器响应信息。其实这种代码也适用于聊天程序设计，向服务器发送信息，获取对方经服务器传来的信息。
import javax.microedition.midlet.*;
import javax.microedition.io.*;
import java.io.*;
public class ViewFile extends MIDlet
{
private String url = "http://www.corej2me.com/midpbook_v1e1/ch14/getHeaderInfo.txt";
public void startApp()
{
try
{
processRequest();
}
catch (Exception e)
{
System.err.println("Msg: " + e.toString());
}
}
private void processRequest() throws IOException
{
HttpConnection http = null;
InputStream iStrm = null;
try
{
// Create the connection
http = (HttpConnection) Connector.open(url);
//----------------
// Client Request
//----------------
// 1) Send request method
http.setRequestMethod(HttpConnection.GET);
// 2) Send header information (this header is optional)
http.setRequestProperty("User-Agent", "Profile/MIDP-1.0 Configuration/CLDC-1.0");
// http.setRequestProperty("If-Modified-Since", "Mon, 16 Jul 2001 22:54:26 GMT");
// If you experience IO problems, try
// removing the comment from the following line
//http.setRequestProperty("Connection", "close");
// 3) Send body/data - No data for this request
//----------------
// Server Response
//----------------
System.out.println("url: " + url);
System.out.println("-------------------------");
// 1) Get status Line
System.out.println("Msg: " + http.getResponseMessage());
System.out.println("Code: " + http.getResponseCode());
// 2) Get header information
if (http.getResponseCode() == HttpConnection.HTTP_OK)
{
System.out.println("field 0: " + http.getHeaderField(0));
System.out.println("field 1: " + http.getHeaderField(1));
System.out.println("field 2: " + http.getHeaderField(2));
System.out.println("-------------------------");
System.out.println("key 0: " + http.getHeaderFieldKey(0));
System.out.println("key 1 : " + http.getHeaderFieldKey(1));
System.out.println("key 2: " + http.getHeaderFieldKey(2));
System.out.println("-------------------------");
System.out.println("content: " + http.getHeaderField("content-type"));
System.out.println("date: " + http.getHeaderField("date"));
System.out.println("last-modified: " + http.getHeaderField("last-modified"));
System.out.println("-------------------------");
// 3) Get data (show the file contents)
String str;
iStrm = http.openInputStream();
int length = (int) http.getLength();
if (length != -1)
{
// Read data in one chunk
byte serverData[] = new byte[length];
iStrm.read(serverData);
str = new String(serverData);
}
else // Length not available...
{
ByteArrayOutputStream bStrm = new ByteArrayOutputStream();
// Read data one character at a time
int ch;
while ((ch = iStrm.read()) != -1)
bStrm.write(ch);
str = new String(bStrm.toByteArray());
bStrm.close();
}
System.out.println("File Contents: " + str);
//-----------------------------
// Show connection information
//-----------------------------
System.out.println("Host: " + http.getHost());
System.out.println("Port: " + http.getPort());
System.out.println("Type: " + http.getType());
// System.out.println("File: " + http.getFile());
// System.out.println("Protocol: " + http.getProtocol());
// System.out.println("URL: " + http.getURL());
// System.out.println("Query: " + http.getQuery());
}
}catch(Exception e){
e.printStackTrace();
}finally{
// Clean up
if (iStrm != null)
iStrm.close();
if (http != null)
http.close();
}
}
public void pauseApp(){}
public void destroyApp(boolean unconditional){ }
}