import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;import my.httpClient.MD5Helper;import org.apache.http.client.cache.HttpCacheEntry;
import org.apache.http.client.cache.HttpCacheStorage;
import org.apache.http.client.cache.HttpCacheUpdateCallback;
import org.apache.http.client.cache.HttpCacheUpdateException;public class DiskCache implements HttpCacheStorage { public DiskCache() { } public HttpCacheEntry getEntry(String url) throws IOException { HttpCacheEntry entry = null; // 一个文件一个缓存项,使用 请求的url进行hash
String path = getPath(url);
// System.out.println("path:" + path);
// 判断文件是否存在
File file = new File(path);
if (file.exists() == false) {
return null;
} try {
ObjectInputStream in = new ObjectInputStream(new FileInputStream(
path));
entry = (HttpCacheEntry) in.readObject();
in.close();
// System.out.println("object read here:");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} return entry; } public void putEntry(String url, HttpCacheEntry entry) throws IOException { String path = getPath(url); ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(
path));
out.writeObject(entry); // System.out.println("object has been written..");
out.close(); } public void removeEntry(String url) throws IOException { String path = getPath(url); // 判断文件是否存在
File file = new File(path);
if (file.exists() == true) { file.delete();
}
} public void updateEntry(String url, HttpCacheUpdateCallback callback)
throws IOException, HttpCacheUpdateException { String path = getPath(url);
HttpCacheEntry existingEntry = null; // 判断文件是否存在,若文件存在,则取出文件的内容
File file = new File(path);
if (file.exists() == true) { ObjectInputStream in = new ObjectInputStream(new FileInputStream(
path));
try {
existingEntry = (HttpCacheEntry) in.readObject();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
in.close();
System.out.println("object read here:");
} HttpCacheEntry updatedEntry = callback.update(existingEntry); // 获取更新过的缓存实体 // 不管存在不存在,都用保存新的实体项。
putEntry(url, updatedEntry); } /*
* 根据url地址获取缓存项在文件系统中的存储地址
*/
private String getPath(String url) {
String key = MD5Helper.string2MD5(url);
String path = "c:\\http-cache\\" + key;
return path;
}}
参考资料:
http://hc.apache.org/httpcomponents-client-ga/httpclient-cache/xref/index.html
http://hc.apache.org/httpcomponents-client-ga/httpclient-cache/xref/org/apache/http/impl/client/cache/ManagedHttpCacheStorage.html