gettext_form.java

j2me的数据库系统开发的经典案例

package connectpacket;

import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import java.io.*;//要用到inputStream outputStream 
import javax.microedition.io.*;//要用到httpconnection

public class GetText_Form extends Form implements CommandListener {
	private GetText_MIDlet gtm;
	private Command exitCommand;
	private HttpConnection http_con=null;
	private InputStream is=null;
	private OutputStream os=null;
	private DataOutputStream dos=null;
	public GetText_Form(GetText_MIDlet gtm,String str_url)
	{
		super("GetText_Form");
		this.gtm=gtm;
		exitCommand=new Command("<Exit>",Command.EXIT,1);
		this.addCommand(exitCommand);
		this.setCommandListener(this);
		try
		{
			if(http_con==null)
			{
				http_con=(HttpConnection)javax.microedition.io.Connector.open(str_url);
				http_con.setRequestMethod(HttpConnection.GET);
				http_con.setRequestProperty("if_Modified-Since", "5 April 2007 20:00:00 GMT");
				http_con.setRequestProperty("User_Agent","Profile/MIDP-2.0 Configuration/CLDC+1.0");
			}
			if(is==null||os==null)
			{
				is=http_con.openInputStream();
				os=http_con.openOutputStream();
			}
			
			//BufferedReader br=new BufferedReader(new InputStreamReader(is));//在j2me里面去除了bufferedreader类
			InputStreamReader isr=new InputStreamReader(is);
			int temp_length=is.available();//获取字节流的长度
		    char []buf=new char[temp_length];
			isr.read(buf,0,buf.length);
			this.append(String.valueOf(buf,0,buf.length));
			//以下尝试想字节输出流中写东西...全高失败//
			/*
			  os.write("123adsf".getBytes());
			 */
			
			/*int key_code=0;
				ByteArrayOutputStream bos=new ByteArrayOutputStream();
				while((key_code=is.read())!=-1)
				{
	                bos.write(key_code);
	                bos.flush();
					 
				}
				byte []buf_text=bos.toByteArray();
				 DataInputStream dis=new DataInputStream(new ByteArrayInputStream(buf_text));
				 this.append(dis.readUTF());
			 */
			/*
				  if(dos==null)
				{
				  dos=http_con.openDataOutputStream();
				  dos.writeUTF("123adsf我很感动你门的热烈欢迎，同时感谢你们的热情招待，预祝你们成功");
				}
			*/
			
			/*
				  OutputStreamWriter osr=new OutputStreamWriter(os);
				osr.write("adsfads123001220");
			*/
				
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
		
	}

	public void commandAction(Command c, Displayable arg1) {
		// TODO 自动生成方法存根

		 if(c==exitCommand)
		 {
			 gtm.quitApp();
		 }
	}

}