URl编程

1.URL(Uniform Resource Locator)的理解:

• 统一资源定位符，对应着互联网的某一资源地址

2.URL的5个基本结构：

• http://localhost:8080/examples/beauty.jpg?username=Tom

• 协议 主机名 端口号 资源地址 参数列表

  3.如何实例化:

• URL url = new URL(“http://localhost:8080/examples/beauty.jpg?username=Tom”);;)

4.常用方法：

5.可以读取、下载对应的url资源：

public static void main(String[] args) {
    HttpURLConnection urlConnection = null;
    InputStream is = null;
    FileOutputStream fos = null;
    try {
        URL url = new URL("http://localhost:8080/examples/beauty.jpg");
        urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.connect();
        is = urlConnection.getInputStream();
        fos = new FileOutputStream("day10\\beauty3.jpg");
        byte[] buffer = new byte[1024];
        int len;
        while((len = is.read(buffer)) != -1){
            fos.write(buffer,0,len);
        }
        System.out.println("下载完成");
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        //关闭资源
        if(is != null){
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if(fos != null){
            try {
                fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if(urlConnection != null){
            urlConnection.disconnect();
        }
    }
}