java应用程序与网络通讯一直是我的弱项,想补一补,就从这一篇开始吧!
以从网上下载一个图象为例:
		
				import
				 java.io.BufferedInputStream;
				import
				 java.io.BufferedOutputStream;
				import
				 java.io.File;
				import
				 java.io.FileOutputStream;
				import
				 java.io.IOException;
				import
				 java.net.URL;
				import
				 java.net.URLConnection;
				public
				 
				class
				 DownloadFormURL {
    
				public
				 
				static
				 
				void
				 main(String[] args) {
        
				try
				 {
            
				new
				 DownloadFormURL().downloadFile(
				"
				
						http://127.0.0.1:8080/image/f.jpg
				
				"
				, 
				new
				 File(
				"
				F:/image.jpg
				"
				));
        } 
				catch
				 (IOException e) {
            e.printStackTrace();
        }
    }
    
				public
				 
				void
				 downloadFile(String sourceURL, File targetFile) 
				throws
				 IOException {
        URL url 
				=
				 
				new
				 URL(sourceURL);
        URLConnection connection 
				=
				 url.openConnection();
        java.io.InputStream inputStream 
				=
				 connection.getInputStream();
        FileOutputStream outputStream 
				=
				 
				new
				 FileOutputStream(targetFile);
        BufferedInputStream in 
				=
				 
				null
				;
        BufferedOutputStream out 
				=
				 
				null
				;
        
				byte
				 buffer[] 
				=
				 
				new
				 
				byte
				[
				8192
				];
        
				try
				 {
            in 
				=
				 
				new
				 BufferedInputStream(inputStream, buffer.length);
            out 
				=
				 
				new
				 BufferedOutputStream(outputStream, buffer.length);
            
				int
				 total 
				=
				 
				0
				;
            
				for
				 (
				int
				 bytesRead 
				=
				 
				0
				; (bytesRead 
				=
				 in.read(buffer)) 
				!=
				 
				-
				1
				;) {
                out.write(buffer, 
				0
				, bytesRead);
                total 
				+=
				 bytesRead;
            }
        } 
				finally
				 {
            in.close();
            out.close();
        }
        
				return
				;
    }
}
		 
		
				
		
		小试了一下,还不错!