Java复习第一天---Javascript的基本知识点(二)
2014-11-23 17:52:35
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accessFile.setLength(fileLength);
// 关闭操作
accessFile.close();
// 首先计算出每个线程下载的大小 开始位置 结束位置
int threadSize = fileLength / threadNum;
// for循环开启线程处理
for (int threadId = 1; threadId <= 3; threadId++) {
int startIndex = (threadId - 1)
* threadSize;// 开始位置
int endIndex = threadId * threadSize - 1;
if (threadId == threadNum) {// 最后一个线程
endIndex = fileLength - 1;
}
System.out.println(当前线程-- + threadId
+ 开始位置--- + startIndex
+ 结束位置--- + endIndex + 线程大小---);
// 开启线程下载要用Start方法
new DownLoadThread(threadId, startIndex,
endIndex, spec, fileName).start();
}
} else {
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this,
设备的SD卡不可用, Toast.LENGTH_LONG)
.show();
}
});
}
} else {
// 这里用这个可以让它在主线程中运行
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this,
服务器端返回错误, Toast.LENGTH_LONG)
.show();
}
});
}
} catch (Exception e) {
e.printStackTrace();
}
};
}.start();
}
}
class DownLoadThread extends Thread {
private int threadId;
private int startIndex;
private int endIndex;
private String path;
private String fileName;
public DownLoadThread(int threadId, int startIndex, int endIndex,
String path, String fileName) {
super();
this.threadId = threadId;
this.startIndex = startIndex;
this.endIndex = endIndex;
this.path = path;
this.fileName = fileName;
}
@Override
public void run() {
// 可以通过每个线程去下载文件了。
try {
File sdfile = Environment.getExternalStorageDirectory();
// 获取每个线程下载的记录文件
File recordFile = new File(sdfile, threadId + .txt);
// 判断记录文件是否存在
if (recordFile.exists()) {
// 读取文件的内容
InputStream is = new FileInputStream(recordFile);
// 利用工具类转换
String value = StreamTools.streamTostr(is);
// 获取记录位置
int recordIndex = Integer.parseInt(value);
// 记录的位置复制给开始的位置即可
startIndex = recordIndex;
}
// 通过path路径构建URL对象
URL url = new URL(path);
// 通过URL对象的打开连接,返回对象
HttpURLConnection httpURLConnection = (HttpURLConnection) url
.openConnection();
// 设置请求头
httpURLConnection.setRequestMethod(GET);
httpURLConnection.setConnectTimeout(5000);
// 设置下载文件的开始位置和结束位置
httpURLConnection.setRequestProperty(Range, bytes=
+ startIndex + - + endIndex);
// 获取的状态吗
int code = httpURLConnection.getResponseCode();
if (code == 206) {
// 获取每个线程返回的流对象:
InputStream inputStream = httpURLConnection
.getInputStream();
// 获取文件名称 因为已经通过那边传过来了
// String fileName =
// path.substring(path.lastIndexOf(/)+1);
// 外部存储设备的路径
File file = new File(sdfile, fileName);
// 根据文件创建她RandomAccessFile对象
RandomAccessFile raf = new RandomAccessFile(file, rwd);
raf.seek(startIndex);
// 定义读取的长度
int len = 0;
byte buffer[] = new byte[50];
int total = 0;
// 循环读取
while ((len = inputStream.read(buffer)) != -1) {
System.out.println(当前线程-- + threadId + --已经下载了
+ (startIndex + total));
// 创建线程下载记录的文件
RandomAccessFile threadfile = new RandomAccessFile(
new File(sdfile, threadId + .txt), rwd);
threadfile.writeBytes((startIndex + total) + );
threadfile.close();
raf.write(buffer, 0, len);
total += len;
synchronized (MainActivity.this) {
currentProgress += len;
progressBar.setProgress(currentProgress);
// 计算百分比的操作 int
final String percent = currentProgress * 100L
/ progressBar.getMax() + ;
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
tv_pb.setText(当前的进度是: + percent + %);
}
});
RandomAccessFile pbfile = new RandomAccessFile(
new File(sdfile, pb.txt), rwd);
pbfile.writeBytes(progressBar.getMax() + ;
+ currentProgress + ; + percent);
pbfile.close();
}
}
raf.close();
inputStream.close();
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
// System.out.println(当前线程----+threadId+下载完毕);
Toast.makeText(MainActivity.this,
当前线程---- + threadId + 下载完毕,
Toast.LENGTH_LONG).show();
}
});
deleteRecordFiles();
} else {
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this, 服务器端下载错误,
Toast.LENGTH_LONG).show();
}
});
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
public synchronized void deleteRecordFiles() {
File sdfile = Environment.getExternalStorageDirectory();
System.out.println(-------------------------);
threadRunning--;
if (threadRunning == 0) {
for (int i = 1; i <= 3; i++) {
File recordFile = new File(sdfile, i + .txt);
if (recordFile.exists()) {
boolean flag1 = recordFile.delete();// 删除掉文件
System.out.println(下载记录 + i + 文件已 + flag1 + 删除);
}
File pdFile = new File(sdfile, pb.txt);
if (pdFile.exists()) {
boolean flag2 = pdFile.delete();
System.out.println(进度条记录文件已 + flag2 + 删除);
}
}
}
}
public void displayMsg() {
}
}
BUG注意事项:
1、继续线程下载的文件一定要执行threadfile.close(),不然就无法执行后面的删除TXT文件部分。
2、一定要注意下载速度的设置,不能太快,超过传输文件的大小,不然会导致模拟器死掉。;