android之下载文件

使用场景：用tomcat搭建了一个文件服务器，然后在安卓端去下载文件。

使用技术：使用 HttpURLConnection 建立http连接，并下载

package com.example.facecompare.FaceApi;

import android.content.Context; import android.util.Log;

import java.io.BufferedReader; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.URL;

public class ModelDownload { /* * 获取http连接处理类HttpURLConnection */ private HttpURLConnection getConnection(String strUrl) { URL url; HttpURLConnection urlcon = null; try { url = new URL(strUrl); urlcon = (HttpURLConnection) url.openConnection(); } catch (Exception e) { e.printStackTrace(); } return urlcon; }

/*
 * 写文件到sd卡 demo
 * 前提需要设置模拟器sd卡容量，否则会引发EACCES异常
 * 先创建文件夹，在创建文件
 */
public boolean down2sd(String strUrl, String filename, downhandler handler)
{
    HttpURLConnection urlcon = getConnection(strUrl);
    if (urlcon == null){
        return false;
    }
    File file = new File(filename);

    FileOutputStream outputStream = null;
    try {
        int currentSize =0;
        int totalSize =0;
        InputStream inputStream = urlcon.getInputStream();
        if (200 != urlcon.getResponseCode()){
            return false;
        }
        totalSize = urlcon.getContentLength();
        outputStream = new FileOutputStream(file);
        byte[] buffer = new byte[1024*10];
        while (true) {
            int iReadSize = inputStream.read(buffer);
            if (-1 == iReadSize){
                break;
            }
            outputStream.write(buffer,0,iReadSize);
            //同步更新数据
            currentSize = currentSize+iReadSize;
            handler.setSize(currentSize,totalSize);
        }
        inputStream.close();
    } catch (Exception e) {
        return false;
    } finally {
        try {
            outputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return true;
}

/*
 * 内部回调接口类
 */
public abstract static class downhandler
{
    public abstract void setSize(int currentSize,int totalSize);
}

} 使用方法：

                    ModelDownload load = new ModelDownload();
                    load.down2sd("http://192.168.31.16:8080/download/"+modelName,storagePath,new ModelDownload.downhandler(){

                        @Override
                        public void setSize(int currentSize, int totalSize) {
                            item.put("DownState",currentSize+"/"+totalSize);
                            Message mes = mHandle.obtainMessage();
                            mes.what = 100;
                            mHandle.sendMessage(mes);
                        }