Java实现网络图片下载 / java 图片下载小工具

/**
*
* @param fromUrl 从哪里download？ 该图片的原始路径 比如：http://c.hiphotos.baidu.com/image/pic/item/c2cec3fdfc039245c4556c698494a4c27c1e25f7.jpg
* @param toUrl download到那里去？ D:/test/myImg/
* @param newFileName 新文件名称  my_first.jpg
* @return
* @throws IOException
*/
public static String DownloadFile(String fromUrl,String toUrl,String newFileName) throws IOException{

        URLConnection con=null;
        URL theUrl=null;
        try {
            theUrl=new URL(fromUrl);//建立地址
            con = theUrl.openConnection();//打开连接
            con.setConnectTimeout(30000);
            con.connect();//连接
        } catch (MalformedURLException e) {
            return "给定的URL地址有误，请查看";
        }
        catch (IOException e) {
            return "无法连接到远程机器，请重试！";
        }
        File filePath = new File(toUrl);
        if(filePath.exists()==false){
        filePath.mkdirs();
        }
        File file=new File(toUrl+newFileName);
        if(!file.exists()){
        file.createNewFile();
        }
        String type = con.getContentType();
        if (type != null) {
            byte[] buffer = new byte[4 * 1024];
            int read;
            try {
                FileOutputStream os = new FileOutputStream(file);
                InputStream in = con.getInputStream();//重定向输入
                while ((read = in.read(buffer)) > 0) {//读取输出
                    os.write(buffer, 0, read);//写入本地文件
                }
                os.close();
                in.close();
            } catch (FileNotFoundException e) {
            e.printStackTrace();
                return "所要下载的文件不存在！";
            }catch (IOException e) {
            e.printStackTrace();
                return "读取远程文件时出错！";
            }
        } else {
            return "文件未找着:"+fromUrl;
        }
        return "拷贝成功";
    }