Httpclient 实现文件下载

依赖jar包：

httpclient-4.0.jar

类的实现：

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import java.io.*;

/**
 * Created by IntelliJ IDEA.
 * User: haoshihai
 * Date: 13-6-17
 * Time: 下午5:22
 * To change this template use File | Settings | File Templates.
 */
public class DownLoad {
    private String workPath = null;
    private String downLoadUrl = null;
    private DefaultHttpClient httpClient = new DefaultHttpClient();

    public void downLoad(String url, String dst) {
        try {
            HttpGet httpGet = new HttpGet(url);
            HttpResponse httpResponse = httpClient.execute(httpGet);
            HttpEntity entity = httpResponse.getEntity();
            InputStream in = entity.getContent();
            long length=entity.getContentLength();
            if(length<=0){
                System.out.println("下载文件不存在！");
                return;
            }
            OutputStream out = new FileOutputStream(new File(dst));
            saveTo(in, out);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void saveTo(InputStream in, OutputStream out) throws Exception {
        byte[] data = new byte[1024*1024];
        int index =0;
        while ((index=in.read(data) )!= -1) {
            out.write(data,0,index);
        }
        in.close();
        out.close();
    }

    public static void main(String args[]) {
        DownLoad downLoad = new DownLoad();
        String url = "http://www.gjt.org/download/time/java/tar/javatar-2.5.tar.gz";
        downLoad.downLoad(url, "E:\\javatar-2.5.tar.gz");
    }
}