火灭中文小说网,墨鲤抄,户外广告网
本文实例为大家分享了android文件下载功能的具体代码，供大家参考，具体内容如下
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！
我要评论
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;
//从输入六中读取数据,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：
步骤：
public class downloader {
//添加@test标记是表示该方法是junit测试的方法,就可以直接运行该方法了
@test
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);
}
}
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);}
}
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持移动技术网。
如对本文有疑问，请在下面进行留言讨论，广大热心网友会与你互动！！ 点击进行留言回复
Android studio开发小型对话机器人app(实例代码)
Android通过Java sdk的方式接入OpenCv的方法
Android 通过cmake的方式接入opencv的方法步骤
Android Studio finish()方法的使用与解决app点击“返回”(直接退出)
Android 进度条 ProgressBar的实现代码(隐藏、出现、加载进度)
网友评论