网络资源下载工具类:java

网络资源下载工具类

import feign.Feign;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import java.io.ByteArrayOutputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import java.util.concurrent.Callable;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.Future;/ * 网络资源下载工具类 */public class URIDownloadUtil {    private final static Logger log = LoggerFactory.getLogger(URIDownloadUtil.class);    private static ExecutorService executorService = Executors.newCachedThreadPool();    /     * 下载资源(异步)     *     * @param url     * @return     * @throws MalformedURLException     * @throws IOException     */    public final static Future<byte[]> asyncDownloadURIToBytes(String url) throws MalformedURLException, IOException { return executorService.submit(() -> {     byte[] result = null;     try {  result = downloadURIToBytes(url);     } catch (Exception e) {  log.error("异步下载资源异常", e);     }     return result; });    }    /     * 下载资源     * @return 资源的二进制数据     */    public final static byte[] downloadURIToBytes(String url) throws MalformedURLException, IOException { HttpURLConnection httpURLConnection; InputStream inputStream = null; ByteArrayOutputStream arrayOutputStream = null; try {     URL url_ = new URL(url);     httpURLConnection = (HttpURLConnection) url_.openConnection();     httpURLConnection.setDoInput(true);     httpURLConnection.setDoOutput(false);     httpURLConnection.setRequestMethod("GET");     httpURLConnection.setConnectTimeout(30000);     httpURLConnection.setReadTimeout(30000);     httpURLConnection.setUseCaches(true);     httpURLConnection.connect();     int code = httpURLConnection.getResponseCode();     log.debug("httpURLConnection ResponseCode = {}", code);     if (code == 200) {  // 将得到的数据转化成InputStream  inputStream = httpURLConnection.getInputStream();  //读取输入流中的数据  arrayOutputStream = new ByteArrayOutputStream();  byte[] buff = new byte[1024];  int len;  while ((len = inputStream.read(buff)) != -1) {      arrayOutputStream.write(buff, 0, len);  }  inputStream.close();  arrayOutputStream.close();  return arrayOutputStream.toByteArray();     } else {  return null;     } } catch (MalformedURLException e) {     log.error("URL错误", e);     throw e; } catch (IOException e) {     log.error("I/O流异常", e);     throw e; } finally {     if (arrayOutputStream != null) {  try {      arrayOutputStream.close();  } catch (IOException e) {      log.error("关闭arrayOutputStream出现异常", e);  }     }     if (inputStream != null) {  try {      inputStream.close();  } catch (IOException e) {      log.error("关闭inputStream出现异常", e);  }     } }    }  }

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