JAVA实现下载网络文件
public class DownloadTest {
public static void downFile(String url, String fileName) throws Exception {
URL u = new URL(url);
//打开连接
HttpURLConnection conn = (HttpURLConnection) u.openConnection();
//设置请求方式为"GET"
conn.setRequestMethod("GET");
//超时响应时间为20秒
conn.setConnectTimeout(20000);
//通过输入流获取图片数据
InputStream is = conn.getInputStream();
//得到图片的二进制数据,以二进制封装得到数据,具有通用性
byte[] data = readInputStream(is);
//创建一个文件对象用来保存图片,创建路径
File file = new File("/sdcard/" + fileName);
if (file.isFile() && file.exists()) {
//文件存在则删除
file.delete();
}
//创建文件
file.createNewFile();
//创建输出流
FileOutputStream outStream = new FileOutputStream(file);
//写入数据
outStream.write(data);
//关闭输出流,释放资源
outStream.close();
}
public static byte[] readInputStream(InputStream inStream) throws Exception {
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
//创建一个Buffer字符串
byte[] buffer = new byte[1024];
//每次读取的字符串长度,如果为-1,代表全部读取完毕
int len;
long total = 0;
//使用一个输入流从buffer里把数据读取出来
while ((len = inStream.read(buffer)) != -1) {
total += len;
//用输出流往buffer里写入数据,中间参数代表从哪个位置开始读,len代表读取的长度
outStream.write(buffer, 0, len);
}
//关闭输入流
inStream.close();
//把outStream里的数据写入内存
return outStream.toByteArray();
}
public static void main(String[] args) throws Exception {
//调用下载方法
downFile("下载链接","文件名");
}
}
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