为了准备LilyBookStore下一步的功能，访问豆瓣的API，今天熟悉了一下JDK和Commons HttpClient中和http相关的接口。Commons中的HttpClient现在已经从Commons中独立出来了，不过新的4.0版还没有stable的release，现在用的3.1还是打着Commons标记的。
JDK实例：
public void exe(String urlAsString) throws IOException{
URL url = new URL(urlAsString);
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
int size = conn.getHeaderFields().size();
for(int i=0; i< size; i++){
System.out.print(conn.getHeaderFieldKey(i)+"\t");
System.out.println(conn.getHeaderField(i));
}
System.out.println("Request Method: "+conn.getRequestMethod());
System.out.println("Response Code: "+conn.getResponseCode());
System.out.println("Response Message: " +conn.getResponseMessage());
System.out.println("Last Modified: " +conn.getLastModified());
System.out.println("ContentHandler: " +conn.getContent().getClass().getName());
InputStream in = (InputStream)conn.getContent();
FileOutputStream out = new FileOutputStream(new File("index.html"));
copyStream(in, out);
}
java.net.HttpURLConnection里主要注意的就是getContent方法，对于不同的请求返回不同的对象。普通网页返回的是sun.net.www.protocol.http.HttpURLConnection$HttpInputStream，而图片、音频文件返回的则是各自的handler。
Commons的HttpClient实例：
public void exe(String urlAsString) throws IOException{
HttpClient client = new HttpClient();
HttpMethod http = new GetMethod(urlAsString);
http.getParams().setParameter(HttpMethodParams.RETRY_HANDLER,
new DefaultHttpMethodRetryHandler(1, false));
client.executeMethod(http);
System.out.println(http.getStatusCode());
System.out.println(http.getStatusText());
InputStream in = http.getResponseBodyAsStream();
FileOutputStream out = new FileOutputStream(new File("index2.html"));
copyStream(in, out);
http.releaseConnection();
}
Commons中除了getResponseBodyAsStream，还有getResponseBodyAsString，使用起来相对方便一些。
等开学以后到学校复杂的网络环境里试一下，再决定最后选择哪个。 | 
转播
