java URL类接口及简单应用

绝地灬酷狼 2022-03-02 15:16 254阅读 0赞

#### URL 类方法 ####

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE2MTgxMQ_size_16_color_FFFFFF_t_70]实例：

import java.net.*;
    import java.io.*;
     
    public class URLDemo
    { 
       public static void main(String [] args)
       { 
          try
          { 
             URL url = new URL("http://www.runoob.com/index.html?language=cn#j2se");
             System.out.println("URL 为：" + url.toString());
             System.out.println("协议为：" + url.getProtocol());
             System.out.println("验证信息：" + url.getAuthority());
             System.out.println("文件名及请求参数：" + url.getFile());
             System.out.println("主机名：" + url.getHost());
             System.out.println("路径：" + url.getPath());
             System.out.println("端口：" + url.getPort());
             System.out.println("默认端口：" + url.getDefaultPort());
             System.out.println("请求参数：" + url.getQuery());
             System.out.println("定位位置：" + url.getRef());
          }catch(IOException e)
          { 
             e.printStackTrace();
          }
       }
    }

结果：

URL 为：http://www.runoob.com/index.html?language=cn#j2se
    协议为：http
    验证信息：www.runoob.com
    文件名及请求参数：/index.html?language=cn
    主机名：www.runoob.com
    路径：/index.html
    端口：-1
    默认端口：80
    请求参数：language=cn
    定位位置：j2se

#### URLConnections 类方法 ####

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE2MTgxMQ_size_16_color_FFFFFF_t_70 1]

import java.net.*;
    import java.io.*;
    public class URLConnDemo
    { 
       public static void main(String [] args)
       { 
          try
          { 
             URL url = new URL("http://www.runoob.com");
             URLConnection urlConnection = url.openConnection();
             HttpURLConnection connection = null;
             if(urlConnection instanceof HttpURLConnection)
             { 
                connection = (HttpURLConnection) urlConnection;
             }
             else
             { 
                System.out.println("请输入 URL 地址");
                return;
             }
             BufferedReader in = new BufferedReader(
             new InputStreamReader(connection.getInputStream()));
             String urlString = "";
             String current;
             while((current = in.readLine()) != null)
             { 
                urlString += current;
             }
             System.out.println(urlString);
          }catch(IOException e)
          { 
             e.printStackTrace();
          }
       }
    }

结果：

$ javac URLConnDemo.java 
    $ java URLConnDemo
    .....这里会输出菜鸟教程首页(http://www.runoob.com)的 HTML 内容.....

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE2MTgxMQ_size_16_color_FFFFFF_t_70]: /images/20220302/7d31d0fc26ed46198a903d7dd4cf3cf8.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE2MTgxMQ_size_16_color_FFFFFF_t_70 1]: /images/20220302/69a758a9b9024bfa91db89bed8fb2523.png