java servlet中上传文件的简单实现（基于第三方jar）
这里的案例使用了两种文件上传的组件、分别介绍
1、使用JSPSmartUpload完成上传
1 package test_servlet_package; 2 3 import java.io.File; 4 import java.io.IOException; 5 import java.util.Calendar; 6 import java.util.Random; 7 import javax.servlet.ServletException; 8 import javax.servlet.http.HttpServlet; 9 import javax.servlet.http.HttpServletRequest; 10 import javax.servlet.http.HttpServletResponse; 11 import com.jspsmart.upload.SmartUpload; 12 13 public class test_servlet_SmartUpload extends HttpServlet { 14 15 String tempPath = "D:\\test"; 16 String filePath = "D:\\filePath"; 17 @Override 18 protected void doPost(HttpServletRequest request, HttpServletResponse response) 19 throws ServletException, IOException { 20 response.setCharacterEncoding("GBK"); 21 SmartUpload mySmartUpload = new SmartUpload(); 22 // 初始化 23 mySmartUpload.initialize(getServletConfig(), request, response); 24 long file_size_max = 4000000; 25 String ext = ""; 26 try { 27 mySmartUpload.setAllowedFilesList("jpg,gif,png"); 28 mySmartUpload.upload();// 上载文件 29 } catch (Exception e) { 30 response.getWriter().write("<script> alert('只允许上传.jpg和.gif类型图片文件');</script>"); 31 } 32 try { 33 com.jspsmart.upload.File myFile = mySmartUpload.getFiles().getFile(0); 34 if (!myFile.isMissing()) { 35 ext = myFile.getFileExt(); // 取得后缀名 36 int file_size = myFile.getSize(); // 取得文件的大小 37 String saveurl = ""; 38 if (file_size < file_size_max) { 39 // 更改文件名，取得当前上传时间的毫秒数值 40 Calendar calendar = Calendar.getInstance(); 41 String filename = String.valueOf(calendar.getTimeInMillis()); 42 Random r = new Random(); 43 String ram = String.valueOf(r.nextInt(1241241241)); 44 filename = filename + ram; 45 filename = filename.substring(0, (filename.length() - ext.length() - 1)); 46 //saveurl = this.getServletContext().getRealPath("/") + "/uploadFile/" + filename + "." + ext; 47 //System.out.println(saveurl); 48 File uploadFile2 = new File(filePath); 49 if(!uploadFile2.exists()){ 50 uploadFile2.mkdirs(); 51 } 52 myFile.saveAs(filePath+"/"+filename+"." + ext); 53 } 54 } 55 String name = mySmartUpload.getRequest().getParameter("name"); 56 request.setAttribute("name", "name"); 57 request.getSession().setAttribute("name", "name"); 58 request.getSession().getId(); 59 System.out.println(name); 60 } catch (Exception e) { 61 e.printStackTrace(); 62 } 63 request.getRequestDispatcher("/uploadsuccess.jsp").forward(request, response); 64 } 65 }
2、使用commons-fileupload完成文件上传
1 package test_servlet_package; 2 3 import java.io.File; 4 import java.io.IOException; 5 import java.io.PrintWriter; 6 import java.util.Iterator; 7 import java.util.List; 8 import javax.servlet.ServletException; 9 import javax.servlet.http.HttpServlet; 10 import javax.servlet.http.HttpServletRequest; 11 import javax.servlet.http.HttpServletResponse; 12 import org.apache.commons.fileupload.FileItem; 13 import org.apache.commons.fileupload.disk.DiskFileItemFactory; 14 import org.apache.commons.fileupload.servlet.ServletFileUpload; 15 16 public class test_servlet extends HttpServlet { 17 18 String tempPath = "D:\\test"; 19 String filePath = "D:\\filePath"; 20 @Override 21 protected void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { 22 res.setContentType("text/plain;charset=gbk"); 23 PrintWriter pw = res.getWriter(); 24 try { 25 DiskFileItemFactory diskFactory = new DiskFileItemFactory(); 26 // threshold 极限、临界值，即硬盘缓存 1M 27 diskFactory.setSizeThreshold(4 * 1024); 28 // repository 贮藏室，即临时文件目录 29 diskFactory.setRepository(new File(tempPath)); 30 ServletFileUpload upload = new ServletFileUpload(diskFactory); 31 // 设置允许上传的最大文件大小 4M 32 upload.setSizeMax(4 * 1024 * 1024); 33 // 解析HTTP请求消息头 34 List<FileItem> fileItems = upload.parseRequest(req); 35 Iterator<FileItem> iter = fileItems.iterator(); 36 while (iter.hasNext()) { 37 FileItem item = (FileItem) iter.next(); 38 if (item.isFormField()) { 39 System.out.println("处理表单内容 ..."); 40 processFormField(item, pw); 41 } else { 42 System.out.println("处理上传的文件 ..."); 43 processUploadFile(item, pw); 44 } 45 } 46 pw.close(); 47 } catch (Exception e) { 48 System.out.println("使用 fileupload 包时发生异常 ..."); 49 e.printStackTrace(); 50 } 51 } 52 53 // 处理表单内容 54 private void processFormField(FileItem item, PrintWriter pw) throws Exception { 55 String name = item.getFieldName(); 56 String value = item.getString(); 57 pw.println(name + " : " + value + "\r\n"); 58 } 59 60 // 处理上传的文件 61 private void processUploadFile(FileItem item, PrintWriter pw) throws Exception { 62 // 此时的文件名包含了完整的路径，得注意加工一下 63 String filename = item.getName(); 64 System.out.println("完整的文件名：" + filename); 65 int index = filename.lastIndexOf("\\"); 66 filename = filename.substring(index + 1, filename.length()); 67 long fileSize = item.getSize(); 68 if ("".equals(filename) && fileSize == 0) { 69 System.out.println("文件名为空 ..."); 70 return; 71 } 72 File uploadFile = new File(filePath + "/" + filename); 73 File uploadFile2 = new File(filePath); 74 if(!uploadFile2.exists()){ 75 uploadFile2.mkdirs(); 76 } 77 item.write(uploadFile); 78 pw.println(filename + " 文件保存完毕 ..."); 79 pw.println("文件大小为 ：" + fileSize + "\r\n"); 80 } 81 }
3、依赖的jar：
1 <classpath> 2 <classpathentry kind="lib" path="base/WEB-INF/lib/commons-fileupload-1.2.2.jar"/> 3 <classpathentry kind="lib" path="base/WEB-INF/lib/commons-io-2.0.1.jar"/> 4 <classpathentry kind="lib" path="base/WEB-INF/lib/jsmartcom_zh_CN.jar"/> 5 <classpathentry kind="lib" path="base/WEB-INF/lib/mysql-connector-java-5.1.21-bin.jar"/> 6 <classpathentry kind="lib" path="base/WEB-INF/lib/taglibs-standard-compat-1.2.1.jar"/> 7 <classpathentry kind="lib" path="base/WEB-INF/lib/taglibs-standard-impl-1.2.1.jar"/> 8 <classpathentry kind="lib" path="base/WEB-INF/lib/taglibs-standard-jstlel-1.2.1.jar"/> 9 <classpathentry kind="lib" path="base/WEB-INF/lib/taglibs-standard-spec-1.2.1.jar"/> 10 <classpathentry kind="output" path="base/WEB-INF/classes"/> 11 </classpath>
