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); 
   } 
  }