URL:Uniform Resource Locator 统一资源定位器
通常情况而言,URl可以有协议名、主机、端口和资源组成,即满足以下格式:
protocol://host:port/resourceName
例如:
http://www.baidu.com/index.php
Public Constructors 构造方法:
URL(String spec) Creates a new URL instance by parsing the string spec. URL(URL context, String spec) Creates a new URL to the specified resource spec. URL(URL context, String spec, URLStreamHandler handler) Creates a new URL to the specified resource spec. URL(String protocol, String host, String file) Creates a new URL instance using the given arguments. URL(String protocol, String host, int port, String file) Creates a new URL instance using the given arguments. URL(String protocol, String host, int port, String file, URLStreamHandler handler) Creates a new URL instance using the given arguments.
常用方法:
String getFile ():获取此URL的资源名
String getHost(): 获取主机名
String getPath ():获取路径
int getPort ():获取端口号
String getProtocol ():获取协议名称
String getQuery():获取此URl的查询字符串部分
URLConnection openConnection():返回一个URLConnection对象,它表示到URl所引用的远程对象的连接
InputStream openStream():打开与此URL的连接,并返回一个用于读取该URL资源的输入流
读取网络资源:
一张图片:
/*
http://www.crazyit.org/attachments/month_1008/20100812_7763e970f822325bfb019ELQVym8tW3A.png
*/
两个功能:
1.以上面网址为参数创建URL对象,获得该对象资源的InputStream,使用BitmapFactory.decodeStream()方法解析出图片 并显示
2.将图片下载下来。
public class MainActivity extends Activity { ImageView show; Bitmap bitmap; Handler handler = new Handler() { public void handleMessage(android.os.Message msg) { if (msg.what == 0x123) { // 使用ImageView显示该图片 show.setImageBitmap(bitmap); } }; }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); show = (ImageView) findViewById(R.id.show); new Thread() { public void run() { try { // 定义一个URL对象 URL url = new URL("http://www.crazyit.org/" + "attachments/month_1008/20100812_7763e970f" + "822325bfb019ELQVym8tW3A.png"); // 打开该URL对应的资源的输入流 InputStream is = url.openStream(); // 从InputStream中解析图片 bitmap = BitmapFactory.decodeStream(is); // 发送消息 通知UI组件显示该图片 handler.sendEmptyMessage(0x123); is.close(); //下载图片 // 再次打开URL对应资源的输入流,创建图片对象 is = url.openStream(); // 打开手机文件对应的输出流 OutputStream os = openFileOutput("crazyit.png", MODE_WORLD_READABLE); byte buff[] = new byte[1024]; int hasRead = 0; // 将图片下载到本地 while ((hasRead = is.read(buff)) > 0) { os.write(buff, 0, hasRead); } is.close(); os.close(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } }; }.start(); } }
时间: 2024-10-23 14:28:28