java使用HTTP代理连接总是能连接的问题

public static void main(String[] argv) throws Exception {
        byte[] b = new byte[1];
        Properties systemSettings = System.getProperties();
        systemSettings.put("http.proxyHost", "23.32.22.83");
        systemSettings.put("http.proxyPort", "915");
        systemSettings.put("proxySet","true");
      
        URL u = new URL("http://www.);
        HttpURLConnection con = (HttpURLConnection) u.openConnection();
            BASE64Encoder encoder = new BASE64Encoder();
            String encodedUserPwd = encoder.encode(" : ".getBytes());
            con.setRequestProperty("Proxy-Authorization", "Basic " + encodedUserPwd);
        DataInputStream di = new DataInputStream(con.getInputStream());
        while (-1 != di.read(b, 0, 1)) {
            System.out.print(new String(b));
        }
        System.out.println("\r\nEND:");
    }