只知道浏览器使用的是HTTP协议，那么如何将网络资源使用JavaHTTP下载下来呢！
这只是一个非常简单的小示例，只是不想每次碰到关于此方面的内容忘了就无从下手！
示例创建HttpURLConnection网络连接，并将这个连接获得的网络数据流写道本地磁盘！
示例代码如下：
Java代码 
- package imageView;
- import java.io.ByteArrayOutputStream;
- import java.io.File;
- import java.io.FileOutputStream;
- import java.io.InputStream;
- import java.net.HttpURLConnection;
- import java.net.URL;
- /**
- * @说明 从网络获取图片到本地
- * @author 崔素强
- * @version 1.0
- * @since
- */
- public class GetImage {
- /**
- * 测试
- * @param args
- */
- public static void main(String[] args) {
- String url = "http://www.baidu.com/img/baidu_sylogo1.gif";
- byte[] btImg = getImageFromNetByUrl(url);
- if(null != btImg && btImg.length > 0){
- System.out.println("读取到：" + btImg.length + " 字节");
- String fileName = "百度.gif";
- writeImageToDisk(btImg, fileName);
- }else{
- System.out.println("没有从该连接获得内容");
- }
- }
- /**
- * 将图片写入到磁盘
- * @param img 图片数据流
- * @param fileName 文件保存时的名称
- */
- public static void writeImageToDisk(byte[] img, String fileName){
- try {
- File file = new File("C:\\" + fileName);
- FileOutputStream fops = new FileOutputStream(file);
- fops.write(img);
- fops.flush();
- fops.close();
- System.out.println("图片已经写入到C盘");
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
- /**
- * 根据地址获得数据的字节流
- * @param strUrl 网络连接地址
- * @return
- */
- public static byte[] getImageFromNetByUrl(String strUrl){
- try {
- URL url = new URL(strUrl);
- HttpURLConnection conn = (HttpURLConnection)url.openConnection();
- conn.setRequestMethod("GET");
- conn.setConnectTimeout(5 * 1000);
- InputStream inStream = conn.getInputStream();//通过输入流获取图片数据
- byte[] btImg = readInputStream(inStream);//得到图片的二进制数据
- return btImg;
- } catch (Exception e) {
- e.printStackTrace();
- }
- return null;
- }
- /**
- * 从输入流中获取数据
- * @param inStream 输入流
- * @return
- * @throws Exception
- */
- public static byte[] readInputStream(InputStream inStream) throws Exception{
- ByteArrayOutputStream outStream = new ByteArrayOutputStream();
- byte[] buffer = new byte[1024];
- int len = 0;
- while( (len=inStream.read(buffer)) != -1 ){
- outStream.write(buffer, 0, len);
- }
- inStream.close();
- return outStream.toByteArray();
- }
- }
package imageView;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
/*** @说明 从网络获取图片到本地* @author 崔素强* @version 1.0* @since*/
public class GetImage {/*** 测试* @param args*/public static void main(String[] args) {String url = "http://www.baidu.com/img/baidu_sylogo1.gif";byte[] btImg = getImageFromNetByUrl(url);if(null != btImg && btImg.length > 0){System.out.println("读取到：" + btImg.length + " 字节");String fileName = "百度.gif";writeImageToDisk(btImg, fileName);}else{System.out.println("没有从该连接获得内容");}}/*** 将图片写入到磁盘* @param img 图片数据流* @param fileName 文件保存时的名称*/public static void writeImageToDisk(byte[] img, String fileName){try {File file = new File("C:\\" + fileName);FileOutputStream fops = new FileOutputStream(file);fops.write(img);fops.flush();fops.close();System.out.println("图片已经写入到C盘");} catch (Exception e) {e.printStackTrace();}}/*** 根据地址获得数据的字节流* @param strUrl 网络连接地址* @return*/public static byte[] getImageFromNetByUrl(String strUrl){try {URL url = new URL(strUrl);HttpURLConnection conn = (HttpURLConnection)url.openConnection();conn.setRequestMethod("GET");conn.setConnectTimeout(5 * 1000);InputStream inStream = conn.getInputStream();//通过输入流获取图片数据byte[] btImg = readInputStream(inStream);//得到图片的二进制数据return btImg;} catch (Exception e) {e.printStackTrace();}return null;}/*** 从输入流中获取数据* @param inStream 输入流* @return* @throws Exception*/public static byte[] readInputStream(InputStream inStream) throws Exception{ByteArrayOutputStream outStream = new ByteArrayOutputStream();byte[] buffer = new byte[1024];int len = 0;while( (len=inStream.read(buffer)) != -1 ){outStream.write(buffer, 0, len);}inStream.close();return outStream.toByteArray();}
}
