URLConnection获取网页的数据

桃扇骨 2022-05-25 00:58 152阅读 0赞

package com.strr.connection;
    
    import java.io.IOException;
    import java.net.URL;
    import java.net.URLConnection;
    import java.nio.charset.StandardCharsets;
    import java.util.Base64;
    import java.util.List;
    import java.util.Map;
    import java.util.Scanner;
    
    public class URLConnectionTest {
        public static void main(String[] args) throws IOException {
            String urlName;
            if (args.length > 0) urlName = args[0];
            else urlName = "http://horstmann.com";
            URL url = new URL(urlName);
            URLConnection connection = url.openConnection();
            if (args.length > 2) {
                String username = args[1];
                String password = args[2];
                String input = username + ":" + password;
                Base64.Encoder encoder = Base64.getEncoder();
                String encoding = encoder.encodeToString(input.getBytes(StandardCharsets.UTF_8));
                connection.setRequestProperty("Authorization", "Basic" + encoding);
            }
            connection.connect();
            Map<String, List<String>> headers = connection.getHeaderFields();
            for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
                String key = entry.getKey();
                for (String value : entry.getValue())
                    System.out.println(key + ":" + value);
            }
            System.out.println("----------------------");
            System.out.println("getContentType: " + connection.getContentType());
            System.out.println("getContentLength: " + connection.getContentLength());
            System.out.println("getContentEncoding: " + connection.getContentEncoding());
            System.out.println("getDate: " + connection.getDate());
            System.out.println("getExpiration: " + connection.getExpiration());
            System.out.println("getLastModify: " + connection.getLastModified());
            System.out.println("----------------------");
            String encoding = connection.getContentEncoding();
            if (encoding == null)
                encoding = "UTF-8";
            try (Scanner in = new Scanner(connection.getInputStream(), encoding)) {
                for (int n = 1; in.hasNextLine() && n <= 10; n++) { 
                    System.out.println(in.nextLine());
                }
                if (in.hasNextLine()) {
                    System.out.println("...");
                }
            }
        }
    }