Java如何从服务器中下载图片

import java.io.IOException; import java.io.InputStream;  import java.io.OutputStream;  import java.net.URL; import java.net.URLConnection; import org.apache.commons.io.IOUtils;    /**   * 从服务器中下载图片   *   * @param fileName 图片地址   * @param response   * @return   */  @RequestMapping(value = "/download")  public void downloadMedia(HttpServletResponse response, HttpServletRequest request) {    InputStream inputStream = null;    OutputStream outputStream = null;    try {      //处理中文乱码      request.setCharacterEncoding("UTF-8");      String fileName = request.getParameter("fileName");      fileName = new String(fileName.getBytes("iso8859-1"),"UTF-8");      //处理浏览器兼容      response.setContentType("application/msexcel;charset=utf-8");//定义输出类型      Enumeration enumeration = request.getHeaders("User-Agent");      String browserName = (String) enumeration.nextElement();      boolean isMSIE = browserName.contains("MSIE");      if (isMSIE) {        response.addHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "UTF8"));      } else {        response.addHeader("Content-Disposition", "attachment;fileName=" + new String(fileName.getBytes("gb2312"), "ISO8859-1"));      }      //url地址如果存在空格，会导致报错！  解决方法为：用+或者%20代替url参数中的空格。      fileName = fileName.replace(" ", "%20");      //图片下载      URL url = new URL(fileName);      URLConnection conn = url.openConnection();      outputStream = response.getOutputStream();      inputStream = conn.getInputStream();      IOUtils.copy(inputStream, outputStream);    } catch (IOException e) {      System.err.println(e);    }finally {       IOUtils.closeQuietly(inputStream);       IOUtils.closeQuietly(outputStream);    }   }