【java】HttpClient实现HTTP文件通用下载工具类

package com.imopan.cps.apart.api.util;import java.io.File;import java.io.FileOutputStream;import java.io.InputStream;import org.apache.http.Header;import org.apache.http.HeaderElement;import org.apache.http.HttpEntity;import org.apache.http.HttpResponse;import org.apache.http.NameValuePair;import org.apache.http.client.HttpClient;import org.apache.http.client.methods.HttpGet;import org.apache.http.impl.client.DefaultHttpClient;/** *   *  HttpClient实现HTTP文件通用下载类 *  maven依赖 * <dependency> *<groupId>org.apache.httpcomponents</groupId> *<artifactId>httpclient</artifactId> *<version>4.0.1</version> * </dependency> *  可下载http文件、图片、压缩文件 *  bug：获取response header中Content-Disposition中filename中文乱码问题 *  @author yuanjianqiang * */public class HttpUtil {public static final int cache = 10 * 1024;public static final boolean isWindows;public static final String splash;public static final String root;static {if (System.getProperty("os.name") != null && System.getProperty("os.name").toLowerCase().contains("windows")) {isWindows = true;splash = "\\";root="D:";} else {isWindows = false;splash = "/";root="/search";}}/** * 根据url下载文件，文件名从response header头中获取 * @param url * @return */public static String download(String url) {return download(url, null);}/** * 根据url下载文件，保存到filepath中 * @param url * @param filepath * @return */public static String download(String url, String filepath) {try {HttpClient client = new DefaultHttpClient();HttpGet httpget = new HttpGet(url);HttpResponse response = client.execute(httpget);HttpEntity entity = response.getEntity();InputStream is = entity.getContent();if (filepath == null)filepath = getFilePath(response);File file = new File(filepath);file.getParentFile().mkdirs();FileOutputStream fileout = new FileOutputStream(file);/** * 根据实际运行效果 设置缓冲区大小 */byte[] buffer=new byte[cache];int ch = 0;while ((ch = is.read(buffer)) != -1) {fileout.write(buffer,0,ch);}is.close();fileout.flush();fileout.close();} catch (Exception e) {e.printStackTrace();}return null;}/** * 获取response要下载的文件的默认路径 * @param response * @return */public static String getFilePath(HttpResponse response) {String filepath = root + splash;String filename = getFileName(response);if (filename != null) {filepath += filename;} else {filepath += getRandomFileName();}return filepath;}/** * 获取response header中Content-Disposition中的filename值 * @param response * @return */public static String getFileName(HttpResponse response) {Header contentHeader = response.getFirstHeader("Content-Disposition");String filename = null;if (contentHeader != null) {HeaderElement[] values = contentHeader.getElements();if (values.length == 1) {NameValuePair param = values[0].getParameterByName("filename");if (param != null) {try {//filename = new String(param.getValue().toString().getBytes(), "utf-8");//filename=URLDecoder.decode(param.getValue(),"utf-8");filename = param.getValue();} catch (Exception e) {e.printStackTrace();}}}}return filename;}/** * 获取随机文件名 * @return */public static String getRandomFileName() {return String.valueOf(System.currentTimeMillis());}/** * 获取response header * @param response */public static void outHeaders(HttpResponse response) {Header[] headers = response.getAllHeaders();for (int i = 0; i < headers.length; i++) {System.out.println(headers[i]);}}public static void main(String[] args) {//String url = "http://bbs.btwuji.com/job.php?action=download&pid=tpc&tid=320678&aid=216617";String url="http://api.gfan.com/market/api/apk?type=WAP&cid=99&uid=-1&pid=1h78UtiFQv4ioruN/Z7gWW+iLrL+AjG7&sid=PEHHOSpUGP1hfoViijqdTQ==";//String filepath = "D:\\test\\a.torrent";String filepath = "D:\\test\\a.apk";HttpUtil.download(url, filepath);}}