postdemo.java

语言：英文 主要是介绍企业J2ME开发

/*
 * PostDemo.java
 *
 * Created on 2005-1-4, 10:50
 */

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.io.*;
import java.io.*;

public class PostDemo extends MIDlet
        implements CommandListener {
    private Display myDisplay = null;
    
    private static String defaultURL =
            "http://localhost:8084/HttpPOSTExampleServlet/ResponseLargeData";
    
    private Form formMain;
    private Form formResult;
    
    private TextField requestField;
    private StringItem resultField;
    
    Command cmdSend = new Command("POST", Command.OK, 1);
    Command cmdBack = new Command("返回", Command.OK, 1);
    
    public PostDemo(){
        myDisplay = Display.getDisplay(this);
        formMain = new Form("Type in a URL:");
        requestField =
                new TextField(null, defaultURL, 100, TextField.URL);
        formMain.append(requestField);
        formMain.addCommand(cmdSend);
        formMain.setCommandListener(this);
    }
    
    public void startApp() {
        myDisplay.setCurrent(formMain);
    }
    
    public void pauseApp() {
    }
    
    public void destroyApp(boolean unconditional) {
        Display myDisplay = null;
        formMain = null;
        requestField = null;
        formResult = null;
        resultField = null;
    }
    
    public void commandAction(Command c, Displayable s) {
        if (c == cmdSend) {
            String urlstring = requestField.getString();
            String resultstring = "";
            try {
                resultstring = sendPostRequest(urlstring);
            } catch (IOException e) {
                resultstring = "ERROR";
            }

            formResult = new Form("POST Result:");
            resultField = new StringItem(null, resultstring);
            formResult.append(resultField);
            formResult.addCommand(cmdBack);
            formResult.setCommandListener(this);
            myDisplay.setCurrent(formResult);
        } else if (c == cmdBack) {
            requestField.setString(defaultURL);
            myDisplay.setCurrent(formMain);
        }
    }

    public String sendPostRequest(String urlstring) throws IOException {
        HttpConnection hc = null;
        DataInputStream dis = null;
        DataOutputStream dos = null;
        InputStream is = null;
        OutputStream os = null;
        String message = "";
        
        //向服务器发送的字符串
        String requeststring = "test large data reading";
        
        try {
            hc = (HttpConnection)
            Connector.open(urlstring, Connector.READ_WRITE);
            hc.setRequestMethod(HttpConnection.POST);

            os = hc.openOutputStream();
            System.out.println("hc.openOutputStream() 成功");
            
            byte[] request_body = requeststring.getBytes();
            for (int i = 0; i < request_body.length; i++) {
                os.write(request_body[i]);
                System.out.println((char)request_body[i]);
            }
            
            os.flush();
            System.out.println(" os.flush(); 成功\n");
            
            int rc = hc.getResponseCode();
            if (rc != HttpConnection.HTTP_OK) {
                throw new IOException("HTTP 响应代码: " + rc);
            }
            
            is = hc.openInputStream();
            System.out.println(" hc.openInputStream() 成功");
            
            System.out.println("\n从服务器读取数据...\n");
            int size=0;
            int ch;
            while ((ch = is.read()) != -1) {
                message = message + (char) ch;
                size++;
                System.out.print((char)ch);
            }
            
            message = "\n\n读取完成\n" +
                    "\n读取的字节数为："+ size +"\n" + message;
            System.out.println(message);
        } finally {
            if (hc != null) {
                hc.close();
                hc = null;
            }
            
            if (dis != null) {
                dis.close();
                dis = null;
            }
            
            if (dos != null) {
                dos.close();
                dos = null;
            }
            
            if (is != null) {
                is.close();
                is = null;
            }
            
            if (os != null) {
                os.close();
                os = null;
            }
        }
        return message;
    }
}