Java io字符写入 下载网络文件 获取url文件

一 写入字符文件

package test;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.OutputStreamWriter;public class SimpleIOTest {public static void main(String[] args) throws IOException {File file = new File("c:/hello3.txt"); OutputStream os = new FileOutputStream(file);BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os)); //一层一层装饰InputStreamReader isr = new InputStreamReader(System.in);//控制台输入流，用其他也行BufferedReader br = new BufferedReader(isr);String line = null;while((line = br.readLine()) != null  ){bw.write(line);  //写入break;//os.write(line.getBytes());}br.close();bw.close();}}

二 获取url文件 

package test;import java.io.File;import java.io.FileOutputStream;import java.io.OutputStream;import java.net.HttpURLConnection;public class UrlIO {/** *  * @param args */public static void main(String[] args) {try {String fileUrl = "http://www.baidu.com/img/baidu_sylogo1.gif";File file = new File("c:/foo.gif");OutputStream os = new FileOutputStream(file);java.net.URL url = new java.net.URL(fileUrl);HttpURLConnection connection =  (HttpURLConnection) url.openConnection();connection.connect();java.io.InputStream  inputStream = connection.getInputStream();byte[] b = new byte[1024];int i = 0;while ((i = inputStream.read(b)) > 0) {os.write(b, 0, i);}inputStream.close();os.flush();os.close();} catch (Exception ex) {ex.printStackTrace();}}}