Java - Not getting html code from a URL [duplicate]

问题

I want to get the html source code of https://www2.cslb.ca.gov/OnlineServices/CheckLicenseII/LicenseDetail.aspx?LicNum=872423 and for that I am using this method but I am not getting the html source code.

public static String getHTML(URL url) {
    HttpURLConnection conn; // The actual connection to the web page
    BufferedReader rd; // Used to read results from the web page
    String line; // An individual line of the web page HTML
    String result = ""; // A long string containing all the HTML
    try {
        conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        while ((line = rd.readLine()) != null) {
            result += line;
        }
        rd.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return result;
}

回答1:

The server filters out Java's default User-Agent. This works:

public static String getHTML(URL url) {
    try {
        final URLConnection urlConnection = url.openConnection();
        urlConnection.addRequestProperty("User-Agent", "Foo?");
        final InputStream inputStream = urlConnection.getInputStream();
        final String html = IOUtils.toString(inputStream);
        inputStream.close();
        return html;
    } catch (Exception e) {
        throw new RuntimeException(e);
    }

Looks like the user agents are black listed. By default my JDK sends:

User-Agent: Java/1.6.0_26

Note that I'm using IOUtils class to simplify example, but the key things is:

urlConnection.addRequestProperty("User-Agent", "Foo?");

来源：https://stackoverflow.com/questions/8142039/java-not-getting-html-code-from-a-url

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httpurlconnection