J2ME断点下载文件

package downfile;

import java.io.*;

import javax.microedition.io.*;
import javax.microedition.io.file.*;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.AlertType;
import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.Display;
import javax.microedition.midlet.MIDlet;

/**
* <p>Title: </p>
*
* <p>Description: </p>
*
* <p>Copyright: Copyright (c) 2009</p>
*
* <p>Company: </p>
*
* @author new soul
* @version 1.0
*/
public class Load extends Thread {
private String url;//网络文件的地址
private String path;//本地保存路径
private long loadsize=0;//下载文件的大小
private long size=0;//已下载的文件大小
private MIDlet midlet;

/**
* 下载线程
* @param urlstr String 网络文件地址
* @param pathstr String 本地存储路径
* @param mid MIDlet 当前显示主类
* 手机地址为 file:///E:/ 电脑模拟器地址 file://localhost/root1/
*/
public Load(String urlstr,String pathstr,MIDlet mid) {
this.url=urlstr;
this.path=pathstr;
this.midlet=mid;
Thread thread=new Thread(this);
thread.start();
}

public void run() {
try {
LoadFile(url, path);
Alert alert=new Alert("下载提示","下载已完成!",null,AlertType.ALARM);
alert.setTimeout(3000);
Display.getDisplay(midlet).setCurrent(alert);

} catch (Exception ex) {
ex.printStackTrace();
}
}

/**
* 文件的断点下载
* @param urladress String 网络文件的地址
* @param pathstr String 文件存储的本地地址
*/
public void LoadFile(String urladress, String pathstr) {
HttpConnection conn = null;
FileConnection fc = null;
InputStream is = null;
OutputStream os = null;

//截取文件名
String[] urlstr = Tool.Split(urladress, "/");
String filename = urlstr[urlstr.length - 1].toString();

try {
conn = (HttpConnection) Connector.open(url.trim());
conn.setRequestMethod(HttpConnection.POST);

//手机地址为 file:///E:/ 电脑地址file://localhost/root1/
fc = (FileConnection) Connector.open(pathstr + filename,Connector.READ_WRITE);
if (fc.exists())
this.size = fc.fileSize();
conn.setRequestProperty("RANGE", "bytes=" + size + "-"); //断点续传
setLoadsize(conn.getLength());//下载文件长度

is = conn.openInputStream();
int ch;
byte[] b = new byte[1024];

if (!fc.exists()) {//文件不存在
fc.create();
os = fc.openOutputStream();
}

else {//文件已经存在
fc.truncate(size);
os = fc.openOutputStream(size);
}

while ((ch = is.read(b)) != -1) {
os.write(b, 0, ch);
}

fc.close();
os.close();
is.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
}

}

public void setLoadsize(long loadsize) {
this.loadsize = loadsize;
}

public long getLoadsize() {
return loadsize;
}

public long getSize() {
return size;
}

}


本文来自优快云博客，转载请标明出处：http://blog.youkuaiyun.com/laigb/archive/2009/03/15/3992367.aspx