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前端JSP:
后端servlet:
package com.mybank.enterprise.framework.servlet; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.PrintWriter; import java.util.Iterator; import java.util.List; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; import com.mybank.enterprise.util.Constant; import com.mybank.enterprise.util.StringUtil; public class UploadIMGSerlet extends HttpServlet { private static final long serialVersionUID = 1L; // 上传文件的保存路径 private String configPath = Constant.RB.getString("img_path"); // 临时文件路径 private String dirTemp = "resource/temp/"; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String ret_fileName = null;//返回给前端已修改的图片名称 request.setCharacterEncoding("UTF-8"); response.setContentType("text/html; charset=UTF-8"); PrintWriter out = response.getWriter(); // 文件保存目录路径 String savePath = configPath; // 临时文件目录 String tempPath = this.getServletContext().getRealPath("/") + dirTemp; // 创建文件夹 File dirFile = new File(savePath); if (!dirFile.exists()) { dirFile.mkdirs(); } // 创建临时文件夹 File dirTempFile = new File(tempPath); if (!dirTempFile.exists()) { dirTempFile.mkdirs(); } DiskFileItemFactory factory = new DiskFileItemFactory(); factory.setSizeThreshold(20 * 1024 * 1024); // 设定使用内存超过5M时,将产生临时文件并存储于临时目录中。 factory.setRepository(new File(tempPath)); // 设定存储临时文件的目录。 ServletFileUpload upload = new ServletFileUpload(factory); upload.setHeaderEncoding("UTF-8"); try { List> items = upload.parseRequest(request); Iterator> itr = items.iterator(); while (itr.hasNext()) { FileItem item = (FileItem) itr.next(); String fileName = item.getName(); if(fileName!=null){ String endstr = fileName.substring(fileName.indexOf("."),fileName.length()); fileName = StringUtil.createSerial20().concat(endstr); ret_fileName = fileName; } if (!item.isFormField()) { try { File uploadedFile = new File(savePath,fileName); OutputStream os = new FileOutputStream(uploadedFile); InputStream is = item.getInputStream(); byte buf[] = new byte[1024];// 可以修改 1024 以提高读取速度 int length = 0; while ((length = is.read(buf)) > 0) { os.write(buf, 0, length); } // 关闭流 os.flush(); os.close(); is.close(); } catch (Exception e) { e.printStackTrace(); } } } } catch (FileUploadException e) { e.printStackTrace(); } //将已修改的图片名称返回前端 out.print(ret_fileName); out.flush(); out.close(); } }
显示图片servlet
package com.mybank.enterprise.framework.servlet; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.OutputStream; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.mybank.enterprise.util.Constant; public class GetIMGServlet extends HttpServlet { private static final long serialVersionUID = 2761789171087122738L; public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String file = req.getParameter("file"); File pic = new File(Constant.RB.getString("img_path")+file); FileInputStream fis = new FileInputStream(pic); OutputStream os = resp.getOutputStream(); try { int count = 0; byte[] buffer = new byte[1024 * 1024]; while ((count = fis.read(buffer)) != -1) os.write(buffer, 0, count); os.flush(); } catch (IOException e) { e.printStackTrace(); } finally { if (os != null) os.close(); if (fis != null) fis.close(); } } }
img标签的src可以指向servlet只要返回流对象即可,常用的如验证码
参考文章:
http://www.cnblogs.com/yangy608/p/3915337.html