一.项目用到的图片上传的关键方法：
直接使用android-async-http.jar
private void sendImage(Bitmap bm){
ByteArrayOutputStream stream = new ByteArrayOutputStream();
//压缩Bitmap到指定的位图到outputstream
bm.compress(Bitmap.CompressFormat.PNG, 60, stream);
byte[] bytes = stream.toByteArray();
String img = new String(Base64.encodeToString(bytes, Base64.DEFAULT));
AsyncHttpClient client = new AsyncHttpClient();
RequestParams params = new RequestParams();
params.add("img", img);
client.post("http:xxx/postIcon", params, new AsyncHttpResponseHandler() {
@Override
public void onSuccess(int i, Header[] headers, byte[] bytes) {
Toast.makeText(MainActivity.this, "Upload Success!", Toast.LENGTH_LONG).show();
}
@Override
public void onFailure(int i, Header[] headers, byte[] bytes, Throwable throwable) {
Toast.makeText(MainActivity.this, "Upload Fail!", Toast.LENGTH_LONG).show();
}
});
}
二、文件下载
1.普通单线程下载文件：
直接使用URLConnection.openStream()打开网络输入流,然后将流写入到文件中。
public static void downLoad(String path,Context context)throws Exception{
URL url = new URL(path);
InputStream is = url.openStream();
//截取最后的文件名
String end = path.substring(path.lastIndexOf("."));
//打开手机对应的输出流,输出到文件中
OutputStream os = context.openFileOutput("Cache_"+System.currentTimeMillis()+end, Context.MODE_PRIVATE);
byte[] buffer = new byte[1024];
int len = 0;
//从输入流中读取数据,读到缓冲区中
while((len = is.read(buffer)) > 0) {
os.write(buffer,0,len);
}
//关闭输入输出流
is.close();
os.close();
}
2.普通多线程下载：
多线程下载的流程：
1）、获取网络连接
2）、本地磁盘创建相同大小的空文件
3）、计算每条线程需从文件哪个部分开始下载，结束
4）、依次创建，启动多条线程来下载网络资源的指定部分
代码：
public void download() throws Exception {
//设置URL的地址和下载后的文件名
String filename = "meitu.exe";
String path = "http://10.13.20.32:8080/Test/XiuXiu_Green.exe";
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5000);
conn.setRequestMethod("GET");
//获得需要下载的文件的长度(大小)
int filelength = conn.getContentLength();
System.out.println("要下载的文件长度" + filelength);
//生成一个大小相同的本地文件
RandomAccessFile file = new RandomAccessFile(filename, "rwd");
file.setLength(filelength);
file.close();
conn.disconnect();
//设置有多少条线程下载
int threadsize = 3;
//计算每个线程下载的量
int threadlength = filelength % 3 == 0 ? filelength / 3 : filelength + 1;
for (int i = 0; i < threadsize; i++) {
//设置每条线程从哪个位置开始下载
int startposition = i * threadlength;
//从文件的什么位置开始写入数据
RandomAccessFile threadfile = new RandomAccessFile(filename, "rwd");
threadfile.seek(startposition);
//启动三条线程分别从startposition位置开始下载文件
new DownLoadThread(i, startposition, threadfile, threadlength, path).start();
}
int quit = System.in.read();
while ('q' != quit) {
Thread.sleep(2000);
}
}
在DownLoadThread 类中实现下载
private class DownLoadThread extends Thread {
private int threadid;
private int startposition;
private RandomAccessFile threadfile;
private int threadlength;
private String path;
public DownLoadThread(int threadid, int startposition,
RandomAccessFile threadfile, int threadlength, String path) {
this.threadid = threadid;
this.startposition = startposition;
this.threadfile = threadfile;
this.threadlength = threadlength;
this.path = path;
}
public DownLoadThread() {}
@Override
public void run() {
try{
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5000);
conn.setRequestMethod("GET");
//指定从什么位置开始下载
conn.setRequestProperty("Range", "bytes="+startposition+"-");
//System.out.println(conn.getResponseCode());
if(conn.getResponseCode() == 206) {
InputStream is = conn.getInputStream();
byte[] buffer = new byte[1024];
int len = -1;
int length = 0;
while(length < threadlength && (len = is.read(buffer)) != -1){
threadfile.write(buffer,0,len);
//计算累计下载的长度
length += len;
}
threadfile.close();
is.close();
System.out.println("线程"+(threadid+1) + "已下载完成");
}
}catch(Exception ex){System.out.println("线程"+(threadid+1) + "下载出错"+ ex);}
}
}
注意事项：
int filelength = conn.getContentLength(); //获得下载文件的长度(大小);
RandomAccessFile file = new RandomAccessFile(filename, "rwd"); //该类运行对文件进行读写,是多线程下载的核心;
nt threadlength = filelength % 3 == 0 ? filelength/3:filelength+1; //计算每个线程要下载的量;
conn.setRequestProperty("Range", "bytes="+startposition+"-"); //指定从哪个位置开始读写,这个是URLConnection提供的方法;
//System.out.println(conn.getResponseCode()); //这个注释了的代码是用来查看conn的返回码的,我们前面用的都是200, 而针对多线程的话,通常是206,必要时我们可以通过调用该方法查看返回码！;
int quit = System.in.read();while('q' != quit){Thread.sleep(2000);} //这段代码是做延时操作的,因为我们用的是本地下载,可能该方法运行完了,而我们的 线程还没有开启,这样会引发异常,这里的话,让用户输入一个字符,如果是'q'的话就退出。
三、使用DownloadManager更新应用并覆盖安装：
下面的代码可以直接用，加入到项目后，记得为这个内部广播注册一个过滤器
public class UpdateAct extends AppCompatActivity {
//这个更新的APK的版本部分，我们是这样命名的:xxx_v1.0.0_xxxxxxxxx.apk
//这里我们用的是git提交版本的前九位作为表示
private static final String FILE_NAME = "ABCDEFGHI";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
String endpoint = "";
try {
//这部分是获取AndroidManifest.xml里的配置信息的，包名，以及Meta_data里保存的东西
ApplicationInfo info = getPackageManager().getApplicationInfo(getPackageName(), PackageManager.GET_META_DATA);
//我们在meta_data保存了xxx.xxx这样一个数据，是https开头的一个链接，这里替换成http
endpoint = info.metaData.getString("xxxx.xxxx").replace("https", "http");
} catch (PackageManager.NameNotFoundException e) {
e.printStackTrace();
}
//下面的都是拼接apk更新下载url的，path是保存的文件夹路径
final String _Path = this.getIntent().getStringExtra("path");
final String _Url = endpoint + _Path;
final DownloadManager _DownloadManager = (DownloadManager)getSystemService(DOWNLOAD_SERVICE);
DownloadManager.Request _Request = new DownloadManager.Request(Uri.parse(_Url));
_Request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, FILE_NAME + ".apk");
_Request.setTitle(this.getString(R.string.app_name));
//是否显示下载对话框
_Request.setShowRunningNotification(true);
_Request.setMimeType("application/com.trinea.download.file");
//将下载请求放入队列
_DownloadManager.enqueue(_Request);
this.finish();
}
}
//注册一个广播接收器，当下载完毕后会收到一个android.intent.action.DOWNLOAD_COMPLETE
//的广播,在这里取出队列里下载任务，进行安装
public static class Receiver extends BroadcastReceiver {
public void onReceive(Context context, Intent intent) {
final DownloadManager _DownloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
final long _DownloadId = intent.getLongExtra( DownloadManager.EXTRA_DOWNLOAD_ID, 0);
final DownloadManager.Query _Query = new DownloadManager.Query();
_Query.setFilterById(_DownloadId);
final Cursor _Cursor = _DownloadManager.query(_Query);
if (_Cursor.moveToFirst()) {
final int _Status = _Cursor.getInt(_Cursor .getColumnIndexOrThrow(DownloadManager.COLUMN_STATUS));
final String _Name = _Cursor.getString(_Cursor.getColumnIndexOrThrow("local_filename"));
if (_Status == DownloadManager.STATUS_SUCCESSFUL && _Name.indexOf(FILE_NAME) != 0) {
Intent _Intent = new Intent(Intent.ACTION_VIEW);
_Intent.setDataAndType( Uri.parse(_Cursor.getString(_Cursor.getColumnIndexOrThrow(DownloadManager.COLUMN_LOCAL_URI))), "application/vnd.android.package-archive");
_Intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(_Intent);
}
}
_Cursor.close();
}
}