简单的通信（四）----URL类的使用

功能

URL编程，从网络上读取数据；

代码

package com.demo;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

/**
 * 
 * @author Lynn URL五部分： http://192.168.0.128:8080/helloworld/index.jsp
 *
 */
public class Demo07 {
    public static void main(String[] args) throws MalformedURLException {
        // 资源的网络路径；
        URL url = new URL("http://localhost:8080/Test/test.txt");
        System.out.println("协议：" + url.getProtocol());
        System.out.println("端口号:" + url.getPort());
        System.out.println("路径：" + url.getPath());
        System.out.println("文件名：" + url.getFile());
        System.out.println("映射：" + url.getRef());
        System.out.println("查询：" + url.getQuery());
        
    
        //读入文件的内容有两种方法
        //方法一
        //获取输入流；
        InputStream is = null;
        FileOutputStream fos = null;
        byte[] data;
        int len;
        try {
            is = url.openStream();
            fos = new FileOutputStream(new File("test1.txt"));
            data = new byte[1024];
            while((len=is.read(data))!=-1) {
                fos.write(data, 0,len );
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            if(fos!=null) {
                try {
                    fos.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if(is!=null) {
                try {
                    is.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
        
        
        //方法二
        //输入流；
        InputStream is1 = null;
        //输出流；
        OutputStream os = null;
        try {
            URLConnection urlConnection = url.openConnection();
            is1 = urlConnection.getInputStream();
            byte[] data1 = new byte[1024];
            int len1 = 0;
            while((len1=is1.read(data1))!=-1) {
                System.out.println(new String(data1,0,len1));
            }
            
//          urlConnection.setDoOutput(true);
//          os = urlConnection.getOutputStream();
//          
//          os.write("我是添加的内容".getBytes());
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            if(os!=null) {
                try {
                    os.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                
            }
            if(is1!=null) {
                try {
                    is1.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    
        
        
    }
}

运行结果

附

需要开启服务器，这里使用的是tomcat服务器。