【Java】Java从网络读取图片并保存至本地

一、js代码：

代码如下：

/** * 点击下载当前图片 *  */ function downloadThisImage(obj){var tid = $(obj).attr("file_tid");var fileSrc = $(obj).parent().prev().attr("src");window.location.href='../../file/toDownloadHmImage.do?tid='+tid+'&fileSrc='+fileSrc;}

二、图片下载的公共方法

package com.zxct.edu.utils;import java.io.ByteArrayOutputStream;import java.io.InputStream;import java.io.OutputStream;import java.net.URL;import java.net.URLConnection;import javax.servlet.http.HttpServletResponse;public class ImagesUtil {public static void download2(HttpServletResponse response,String urlString, String filename) throws Exception {//new一个URL对象          URL url = new URL(urlString);          //打开链接          URLConnection conn = url.openConnection();                   //超时响应时间为5秒          conn.setConnectTimeout(5 * 1000);          //通过输入流获取图片数据          InputStream inStream = conn.getInputStream();          //得到图片的二进制数据，以二进制封装得到数据，具有通用性          byte[] data = readInputStream(inStream);          //new一个文件对象用来保存图片，默认保存当前工程根目录          //File imageFile = new File(filename);          //创建输出流          OutputStream outStream = response.getOutputStream();        //写入数据          outStream.write(data);          //关闭输出流          outStream.close();  }public static void download(HttpServletResponse response,String urlString, String filename) throws Exception {    // 构造URL    URL url = new URL(urlString);    // 打开连接    URLConnection con = url.openConnection();     //超时响应时间为10秒          con.setConnectTimeout(10 * 1000);      // 输入流    InputStream is = con.getInputStream();    // 1K的数据缓冲    byte[] bs = new byte[1024];    // 读取到的数据长度    int len;    // 输出的文件流    OutputStream os =response.getOutputStream();    // 开始读取    while ((len = is.read(bs)) != -1) {      os.write(bs, 0, len);    }    // 完毕，关闭所有链接    os.close();    is.close();    }  public static byte[] readInputStream(InputStream inStream) throws Exception{          ByteArrayOutputStream outStream = new ByteArrayOutputStream();          //创建一个Buffer字符串          byte[] buffer = new byte[1024];          //每次读取的字符串长度，如果为-1，代表全部读取完毕          int len = 0;          //使用一个输入流从buffer里把数据读取出来          while( (len=inStream.read(buffer)) != -1 ){              //用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度              outStream.write(buffer, 0, len);          }          //关闭输入流          inStream.close();          //把outStream里的数据写入内存          return outStream.toByteArray();      }}

注：download和download2方法均能实现下载。

三、Controller接口方法：

/** * 下载图片文件 * @param request * @param response * @param model * @return * @throws ServletException * @throws IOException * @author zhangsq */@RequestMapping("/toDownloadHmImage.do")public void toDownloadHmImage(HttpServletRequest request, HttpServletResponse response,ModelMap model,String fileSrc,String tid) throws ServletException, IOException {String filePath = fileSrc.substring(0,fileSrc.indexOf("?"));String realname = filePath.substring(filePath.lastIndexOf("/")+1);// 设置响应头，控制浏览器下载该文件response.reset();response.setStatus(HttpServletResponse.SC_OK); response.setHeader("content-disposition", "attachment;filename=" + URLEncoder.encode(realname, "UTF-8"));try {ImagesUtil.download(response,filePath, realname);} catch (Exception e) {e.printStackTrace();ServletOutputStream sos = null;try {response.setContentType("text/html;charset=utf-8");sos = response.getOutputStream();sos.write("<script>alert('下载失败，请与管理员联系~~');</script>".getBytes());sos.flush();} catch (IOException e1) {e1.printStackTrace();}finally{if(null != sos){try {sos.close();} catch (IOException e1) {e1.printStackTrace();}}}}         }