文件上传file upload
使用fileupload组件实现文件上传:
导入
commons-fileupload-1.2.2.jar
commons-io-2.1.jar
官方文档:
// Check that we have a file upload request 检测是否有文件上传的请求
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
/**************************************************************/
// Create a factory for disk-based file items 创建一个基于磁盘文件项目的工厂
DiskFileItemFactory factory = new DiskFileItemFactory();
// Configure a repository 配置存储库(to ensure a secure temp location is used 确保一个安全的临时位置被利用)
ServletContext servletContext = this.getServletConfig().getServletContext();
File repository = (File) servletContext.getAttribute("javax.servlet.context.tempdir");
factory.setRepository(repository);
// Create a new file upload handler
ServletFileUpload upload = new ServletFileUpload(factory);
// Parse the request
List<FileItem> items = upload.parseRequest(request);
/******************************************************************************/
// Create a factory for disk-based file items
DiskFileItemFactory factory = new DiskFileItemFactory();
// Set factory constraints 设置工厂约束
factory.setSizeThreshold(yourMaxMemorySize); //
factory.setRepository(yourTempDirectory); //
// Create a new file upload handler
ServletFileUpload upload = new ServletFileUpload(factory);
// Set overall request size constraint 设置整体请求大小的约束
upload.setSizeMax(yourMaxRequestSize);
// Parse the request
List<FileItem> items = upload.parseRequest(request);
/***********************************************************************/
// Process the uploaded items
Iterator<FileItem> iter = items.iterator();
while (iter.hasNext()) {
FileItem item = iter.next();
if (item.isFormField()) {
processFormField(item);
} else {
processUploadedFile(item);
}
}
/*****************************************************************************/
// Process the uploaded items
Iterator<FileItem> iter = items.iterator();
while (iter.hasNext()) {
FileItem item = iter.next();
if (item.isFormField()) {
processFormField(item);
} else {
processUploadedFile(item);
}
}
/*********************************************************/
1 package com.servlet; 2 3 import java.io.File; 4 import java.io.FileOutputStream; 5 import java.io.IOException; 6 import java.io.InputStream; 7 import java.io.OutputStream; 8 import java.util.List; 9 10 import javax.servlet.ServletException; 11 import javax.servlet.http.HttpServlet; 12 import javax.servlet.http.HttpServletRequest; 13 import javax.servlet.http.HttpServletResponse; 14 15 import org.apache.commons.fileupload.FileItem; 16 import org.apache.commons.fileupload.FileUploadException; 17 import org.apache.commons.fileupload.disk.DiskFileItemFactory; 18 import org.apache.commons.fileupload.servlet.ServletFileUpload; 19 20 public class FileUploadServlet extends HttpServlet { 21 private static final long serialVersionUID = 1L; 22 23 public FileUploadServlet() { 24 super(); 25 } 26 27 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 28 // TODO Auto-generated method stub 29 } 30 31 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 32 33 34 boolean isMultipart = ServletFileUpload.isMultipartContent(request); 35 System.out.println("是否有文件上传:"+isMultipart); 36 37 DiskFileItemFactory factory = new DiskFileItemFactory(); 38 39 factory.setSizeThreshold(1024*512); // 设置内存缓冲区的阀值512k 40 //设置临时存储文件的目录 41 File tempDir = new File("E:\\upload"); 42 factory.setRepository(tempDir); 43 44 ServletFileUpload upload = new ServletFileUpload(factory); 45 upload.setSizeMax(1024*1024*5); //设置上传文件的最大值 5M 46 try { 47 //解析上传文件流,获取FileItem的对象列表 48 List<FileItem> items = upload.parseRequest(request); 49 50 for(FileItem item :items){ 51 if(item.isFormField()){ 52 String name = item.getName(); 53 String value = item.getString(); 54 System.out.println(name+":"+value); 55 }else{//如果是文件域则将文件保存到d:\\file 56 String fieldName = item.getFieldName(); 57 String fileName = item.getName(); 58 String contentType = item.getContentType(); 59 long sizeInBytes = item.getSize(); 60 61 System.out.println("fieldName:"+fieldName); 62 System.out.println("fileName:"+fileName); 63 System.out.println("contentType:"+contentType); 64 System.out.println("sizeInBytes:"+sizeInBytes); 65 66 67 InputStream is = item.getInputStream(); 68 byte [] buffer = new byte[1024]; 69 int len = 0; 70 fileName = "E:\\file\\"+fileName; 71 OutputStream out = new FileOutputStream(fileName); 72 while ((len = is.read(buffer))!=-1){ 73 out.write(buffer,0,len); 74 } 75 out.close();is.close(); 76 77 } 78 } 79 } catch (FileUploadException e) { 80 e.printStackTrace(); 81 } 82 83 } 84 85 }
1 <form action="FileUploadServlet" method="post" enctype="multipart/form-data"> 2 file:<input type="file" name="file"/> 3 <input type="submit" value="Submit"/> 4</form>
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