Java代码如何从网络中获取资源呢?

网络获取资源的实现思路:
    1.定义一个URL对象
	2.借助HttpURLConnection对象打开URL对象
	3.使用getInputStream下载网络上的资源

InputStream in = null;
byte[] data = null;

URL url = new URL("你的url");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();

if (conn.getResponseCode() == HttpURLConnection.HTTP_OK) {
    //conn.getContentLength() 获取到读取的数据流大小
    log.info("文件名={},文件长度={}",fileName,conn.getContentLength());

    in = conn.getInputStream();

    data = new byte[conn.getContentLength()];
    int total = 0;
    int len = 0; 
    //read(byte b[], int off, int len).b为缓冲区;off为读取字节的下标;len为每次读取的长度
    while ((len = in.read(data, total,
	      conn.getContentLength() - total > 1024 ? 1024 : conn.getContentLength() - total)) != -1) {
        total = total + len;
    }
    in.close();
    conn.disconnect();
}