通过http路径获取文本内容（Java）

public static String readFileByUrl(String urlStr) {
    String res = null;
    try {
        URL url = new URL(urlStr);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        //设置超时间为3秒
        conn.setConnectTimeout(3 * 1000);
        //防止屏蔽程序抓取而返回403错误
        conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
        //得到输入流
        InputStream inputStream = conn.getInputStream();
        res = readInputStream(inputStream);
    } catch (Exception e) {
        System.out.println("通过url地址获取文本内容失败");
    }
    return res;
}

/**
 * 从输入流中获取字符串
 *
 * @param inputStream
 * @return
 * @throws IOException
 */
public static String readInputStream(InputStream inputStream) throws IOException {
    byte[] buffer = new byte[1024];
    int len = 0;
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    while ((len = inputStream.read(buffer)) != -1) {
        bos.write(buffer, 0, len);
    }
    bos.close();
    return new String(bos.toByteArray(), "utf-8");
}