安卓 下载文件

 下载文件示例：

String Url = "https://raw.githubusercontent.com/scimence/AndroidPlugin/master/apk/AndroidPlugin_plugin1.apk";
String filePath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/backups/apps/AndroidPlugin_plugin1.apk";

DownloadTool.DownloadFile(Url, filePath);    // 从网络下载文件到本地

package sci.tool.web;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.concurrent.Executors;

/** 调用前需添加权限  */
public class DownloadTool
{
	/** 获取指定网络文件url，保存至本地文件路径filePath */
	public static void DownloadFile(final String url, final String filePath)
	{
		ConfirmFile(filePath);
		
		Executors.newCachedThreadPool().execute(new Runnable()
		{
			@Override
			public void run()
			{
				try
				{
					URL webUrl = new URL(url);
					URLConnection con = webUrl.openConnection();	// 打开连接
					InputStream in = con.getInputStream();			// 获取InputStream
					
					File f = new File(filePath);					// 创建文件输出流
					FileOutputStream fo = new FileOutputStream(f);
					
					byte[] buffer = new byte[1024 * 1024];
					int len = 0;
					while( (len = in.read(buffer)) > 0)		// 读取文件
					{
						fo.write(buffer, 0, len); 			// 写入文件
					}
					
					in.close();
					
					fo.flush();
					fo.close();
				}
				catch (Exception e)
				{
					e.printStackTrace();
				}
			}
		});
	}
	
	/** 创建目录和文件 */
	public static void ConfirmFile(String filePath)
	{
		try
		{
			File f = new File(filePath);
			File parent = f.getParentFile();
			
			if (!parent.exists()) parent.mkdirs();
			if (!f.exists()) f.createNewFile();
		}
		catch (Exception ex)
		{	
			ex.printStackTrace();
		}
	}
}