URL编程demo

傷城~ 2022-08-23 01:41 133阅读 0赞

这个demo前提是在tomcat服务器的webapps的example文件夹下新建一个HelloWorld.txt。并写入一写内容

package myNetDemo;
    
    import static org.junit.Assert.*;
    
    import java.io.File;
    import java.io.FileNotFoundException;
    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;
    
    import org.junit.Test;
    
    public class TestURL {
    
    	// URL统一资源定位符，一个URL对象，对应着互联网上的一个资源
    	// 可以通过URL对象调用其相应的方法，将此资源读取
    	public static void main(String[] args) {
    		// 创建一个url对象
    
    		URL url = null;
    		// 如何将服务端的资源读取进来：openStream()
    		InputStream iStream = null;
    		int len;
    		try {
    			url = new URL("http://127.0.0.1:8080/examples/HelloWorld.txt?a=b");
    
    			/*
    			 * 个方法
    			 * 
    			 * System.out.println(url.getProtocol());
    			 * System.out.println(url.getHost());
    			 * System.out.println(url.getPort());
    			 * System.out.println(url.getPath());
    			 * System.out.println(url.getFile());//URL文件名
    			 * System.out.println(url.getRef());//获取URL在文件中的相对位置
    			 * System.out.println(url.getQuery());//获取URL查询名
    			 */
    
    			iStream = url.openStream();
    			byte[] b = new byte[20];
    			while ((len = iStream.read(b)) != -1) {
    				String string = new String(b, 0, len);
    				System.out.println(string);
    			}
    		} catch (MalformedURLException e1) {
    			// TODO Auto-generated catch block
    			e1.printStackTrace();
    		} catch (IOException e1) {
    			// TODO Auto-generated catch block
    			e1.printStackTrace();
    		} finally {
    			if (iStream != null) {
    				try {
    					iStream.close();
    				} catch (IOException e) {
    					// TODO Auto-generated catch block
    					e.printStackTrace();
    				}
    			}
    		}
    
    		// 即要读进来资源又想写出去资源，：URLConnection
    		InputStream is = null;
    		FileOutputStream fos = null;
    		try {
    			url = new URL("http://127.0.0.1:8080/examples/HelloWorld.txt?a=b");
    			URLConnection connection = url.openConnection();
    			is = connection.getInputStream();
    			fos = new FileOutputStream(new File("out1.txt"));
    
    			byte[] b1 = new byte[20];
    			int len1;
    			while ((len1 = is.read(b1)) != -1) {
    				fos.write(b1, 0, len1);
    			}
    		} catch (FileNotFoundException e1) {
    			// TODO Auto-generated catch block
    			e1.printStackTrace();
    		} catch (IOException e1) {
    			// TODO Auto-generated catch block
    			e1.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();
    				}
    
    			}
    		}
    	}
    
    }