目录

1：通过url请求下载文件

2：从服务器的路径拿到文件

1：通过url请求下载文件

/**
 * URL
 * 类 URL 代表一个统一资源定位符，它是指向互联网“资源”的指针。
 * 抓取文件:以下载一张图片为例
 * 1、创建URL对象  指定文件的URL地址（图片的URL地址）
 * 2、获取远程连接的对象
 * 3、设置获取方式，一般用到GET、POST方式
 * 4、获取HTTP响应的状态码  200表示请求成功
 * 5、字节输入流  读取文件
 * 6、字节输出流  把读取的文件存入本地
 * @author hw
 *
 */
--------------------- 

public class TestDowload {
    public static void main(String[] args) {
        BufferedInputStream bufferedInputStream = null;
        BufferedOutputStream bufferedOutputStream = null;


        try {
            URL url = new URL("https://e-cloudstore.com/files/ecology_dev.zip");
            HttpURLConnection conn=(HttpURLConnection)url.openConnection();
            conn.setRequestMethod("GET");
            //设置URL请求方式  GET方式
            conn.setRequestMethod("GET");
            //从HTTP响应消息获取状态码
            int code=conn.getResponseCode();
               //如果状态码为200表示请求成功
            if(code ==200){
                bufferedInputStream = new BufferedInputStream(conn.getInputStream());
                bufferedOutputStream = new BufferedOutputStream(new FileOutputStream("D://ecology_dev.zip"));


                byte[] by=new byte[1024];
                int len=0;
                while((len=bufferedInputStream.read(by))!=-1) {
                    bufferedOutputStream.write(by, 0, len);
                    //刷新
                    bufferedOutputStream.flush();
                }
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                bufferedInputStream.close();
                bufferedOutputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

2：从服务器的路径拿到文件

public class TestDowload {
    public static void main(String[] args) {
        FileInputStream fileInputStream = null;
        BufferedInputStream bufferedInputStream = null;
        FileOutputStream fileOutputStream = null;
        BufferedOutputStream bufferedOutputStream = null;


        try {
            fileInputStream = new FileInputStream(new File("d://xxx.txt"));
            bufferedInputStream = new BufferedInputStream(fileInputStream);

            fileOutputStream = new FileOutputStream(new File("D:/开发文档/txt"));
            bufferedOutputStream = new BufferedOutputStream(fileOutputStream);

            int tag;
            while ((tag = (bufferedInputStream.read())) != -1) {
                bufferedOutputStream.write(tag);
            }
            bufferedOutputStream.flush();

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fileInputStream!=null){
                try {
                    fileInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (fileOutputStream!=null){
                try {
                    fileOutputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bufferedInputStream!=null){
                try {
                    bufferedInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bufferedOutputStream!=null){
                try {
                    bufferedOutputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }
}