首先給大家介紹一文件的上傳
實體類
import java.sql.Timestamp; /** * * @Decription 文件上傳實體類* */ public class Upfile { private String id;// ID主鍵使用uuid隨機生成private String uuidname; // UUID名稱private String filename;//文件名稱private String savepath; // 保存路徑private Timestamp uploadtime; // 上傳時間private String description;// 文件描述private String username; // 用戶名public Upfile() { super(); } public Upfile(String id, String uuidname, String filename, String savepath, Timestamp uploadtime, String description, String username) { super(); this.id = id; this.uuidname = uuidname; this.filename = filename; this.savepath = savepath; this.uploadtime = uploadtime; this.description = description; this.username = username; } public String getDescription() { return description; } public String getFilename() { return filename; } public String getId() { return id; } public String getSavepath() { return savepath; } public Timestamp getUploadtime() { return uploadtime; } public String getUsername() { return username; } public String getUuidname() { return uuidname; } public void setDescription(String description) { this.description = description; } public void setFilename(String filename) { this.filename = filename; } public void setId(String id) { this.id = id; } public void setSavepath(String savepath) { this.savepath = savepath; } public void setUploadtime(Timestamp uploadtime) { this.uploadtime = uploadtime; } public void setUsername(String username) { this.username = username; } public void setUuidname(String uuidname) { this.uuidname = uuidname; } }頁面
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP 'upload.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <h1>文件上傳</h1> <form action="${pageContext.request.contextPath }/upload" method="post" enctype="multipart/form-data"> <table> <tr> <td> 上傳用戶名:</td> <td><input type="text" name="username"/></td> </tr> <tr> <td> 上傳文件:</td> <td><input type="file" name="file"/></td> </tr> <tr> <td> 描述:</td> <td><textarea rows="5" cols="50" name="description"></textarea></td> </tr> <tr> <td><input type="submit" value="上傳開始"/></td> </tr> </table> </form> <div>${msg }</div> <a href="${pageContext.request.contextPath }/index.jsp">返回主頁</a> </body> </html> Servlet
import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.fileupload.FileUploadBase.FileSizeLimitExceededException; import org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException; import org.apache.commons.fileupload.servlet.ServletFileUpload; import com.itheima.domain.Upfile; import com.itheima.exception.MyException; import com.itheima.service.UpfileService; import com.itheima.service.impl.UpfileServiceImpl; import com.itheima.untils.WebUntil; public class UploadFileServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //判斷表單是不是多個部分組成的if(!ServletFileUpload.isMultipartContent(request)){ request.setAttribute("msg", "表單個設置錯誤,請檢查enctype屬性是是否設置正確"); request.getRequestDispatcher("/upload.jsp").forward(request, response); return ; } //是多部分組成的就獲取並遍歷返回一個文件上傳對象,包含上傳的所有信息try { Upfile upfile=WebUntil.upload(request); UpfileService upfileService=new UpfileServiceImpl(); boolean flag=upfileService.add(upfile); if(flag){ request.setAttribute("msg", "上傳成功"); request.getRequestDispatcher("/upload.jsp").forward(request, response); return ; }else{ request.setAttribute("msg", "上傳失敗,請重試"); request.getRequestDispatcher("/upload.jsp").forward(request, response); return ; } }catch (FileSizeLimitExceededException e) { e.printStackTrace(); request.setAttribute("msg", "單個文件大小,超過最大限制"); request.getRequestDispatcher("/upload.jsp").forward(request, response); return ; } catch (SizeLimitExceededException e) { e.printStackTrace(); request.setAttribute("msg", "總文件大小,超過最大限制"); request.getRequestDispatcher("/upload.jsp").forward(request, response); return ; } } }工具類
import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.UnsupportedEncodingException; import java.util.ArrayList; import java.util.List; import java.util.UUID; import javax.servlet.http.HttpServletRequest; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.FileUploadBase; import org.apache.commons.fileupload.FileUploadBase.FileSizeLimitExceededException; import org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.ProgressListener; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; import com.itheima.domain.Upfile; import com.itheima.exception.MyException; /** * 文件上傳工具類* @Decription TODO * */ public class WebUntil { /** * 文件上傳的方法* @param request 請求參數傳入* @return 返回一個Upfile對象* @throws FileSizeLimitExceededException * @throws SizeLimitExceededException * @throws IOException */ public static Upfile upload(HttpServletRequest request) throws FileSizeLimitExceededException, SizeLimitExceededException { Upfile upfile=new Upfile(); ArrayList<String> fileList=initList(); try { //獲取磁盤文件對象工廠DiskFileItemFactory factory=new DiskFileItemFactory(); String tmp=request.getSession().getServletContext().getRealPath("/tmp"); System.out.println(tmp); //初始化工廠setFactory(factory,tmp); //獲取文件上傳解析器ServletFileUpload upload=new ServletFileUpload(factory); //初始化解析器setUpload(upload); //獲取文件列表集合List<FileItem> list = upload.parseRequest(request); //遍歷for (FileItem items : list) { //判斷是不是普通表單個對象if(items.isFormField()){ //獲取上傳表單的name String fieldName=items.getFieldName(); //value String fieldValue=items.getString("UTF-8"); //判斷if("username".equals(fieldName)){ //設置upfile.setUsername(fieldValue); }else if("description".equals(fieldName)){ //設置屬性upfile.setDescription(fieldValue); } }else{ //是文件就準備上傳//獲取文件名String filename=items.getName(); //處理因為瀏覽器不同而導致的獲得的文件名的差異int index=filename.lastIndexOf("//"); if(index!=-1){ filename=filename.substring(index+1); } //生成隨機的文件名String uuidname=generateFilename(filename); //獲取上傳的文件路徑String savepath=request.getSession().getServletContext().getRealPath("/WEB-INF/upload"); //獲取請求對像中的輸入流InputStream in = items.getInputStream(); //將文件打散存放在不同的路徑,求出路徑savepath=generateRandomDir(savepath,uuidname); //複製文件uploadFile(in,savepath,uuidname); String id=UUID.randomUUID().toString(); upfile.setId(id); upfile.setSavepath(savepath); upfile.setUuidname(uuidname); upfile.setFilename(filename); //清除緩存items.delete(); } } }catch ( FileUploadBase.FileSizeLimitExceededException e) { //拋出出異常throw e; } catch (FileUploadBase.SizeLimitExceededException e) { //拋出出異常throw e; }catch (FileUploadException e) { e.printStackTrace(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } return upfile; } /** * 初始化文件列表* @return */ private static ArrayList<String> initList() { ArrayList<String> list=new ArrayList<String>(); list.add(".jpg"); list.add(".rar"); list.add(".txt"); list.add(".png"); return list; } /** * 複製文件* @param in items中的輸入流* @param savepath 保存路徑* @param uuidname 文件名*/ private static void uploadFile(InputStream in, String savepath, String uuidname) { //獲取文件File file=new File(savepath, uuidname); OutputStream out = null; try { int len=0; byte [] buf=new byte[1024]; //獲取輸出流out = new FileOutputStream(file); while((len=in.read(buf))!=-1){ out.write(buf, 0, len); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); }finally{ try { in.close(); } catch (IOException e) { e.printStackTrace(); } try { out.close(); } catch (IOException e) { e.printStackTrace(); } } } /** * 生成隨機的存放路徑* @param savepath 保存路徑* @param uuidname 生成的uuid名稱* @return * 使用hashcode完成*/ private static String generateRandomDir(String savepath, String uuidname) { //轉化為hashcode System.out.println("上傳路徑"+savepath); System.out.println("UUIDNAME"+uuidname); int hashcode=uuidname.hashCode(); //容器StringBuilder sb=new StringBuilder(); while(hashcode>0){ //與上15 int tmp=hashcode&0xf; sb.append("/"); sb.append(tmp+""); hashcode=hashcode>>4; } //拼接新的路徑String path=savepath+sb.toString(); System.out.println("path"+path); File file=new File(path); //判斷路徑存不存在if(!file.exists()){ //不存在就創建file.mkdirs(); } //返回保存路徑return path; } /** * 生成新的文件名* @param uuidname 隨機的ID名字* @param filename 原來的名* @return */ private static String generateFilename( String filename) { String uuidname=UUID.randomUUID().toString(); return uuidname.replace("-", "").toString()+"_"+filename; } /** * 初始化解析器* @param upload */ private static void setUpload(ServletFileUpload upload) { // 設置字符編碼upload.setHeaderEncoding("utf-8"); //設置文件大小upload.setFileSizeMax(1024*1024*20); //設置總文件大小upload.setSizeMax(1024*1024*50); //設置進度監聽器upload.setProgressListener(new ProgressListener() { public void update(long pBytesRead, long pContentLength, int pItems) { System.out.println("已經讀取: "+pBytesRead+",總共有: "+pContentLength+", 第"+pItems+"個"); } }); } /** * 工廠初始化方法* @param factory * @param tmp 緩衝目錄*/ private static void setFactory(DiskFileItemFactory factory, String tmp) { /// 配置初始化值緩衝區factory.setSizeThreshold(1024*1024); File file=new File(tmp); //設置緩衝目錄factory.setRepository(file); } }二文件下載
Servlet
public class DownupfileServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //獲取ID String id=request.getParameter("id"); //業務層的接口UpfileService upfileService=new UpfileServiceImpl(); //根據ID查找這個對象Upfile upfile=upfileService.findUpfileById(id); if(upfile==null){ return; } //獲取文件的真實名稱String filename=upfile.getFilename(); //如果文件名中有中文,需要轉碼,不然就下載時沒有文件名filename=URLEncoder.encode(filename, "utf-8"); //更改過的名稱String uuidname=upfile.getUuidname(); //保存路徑String savepath=upfile.getSavepath(); File file=new File(savepath,uuidname); //判斷文件是否存在if(!file.exists()){ request.setAttribute("msg", "下載的文件過期了"); request.getRequestDispatcher("/index").forward(request, response); return; } //設置文件下載響應頭信息response.setHeader("Content-disposition", "attachement;filename="+filename); //使用IO流輸出InputStream in = new FileInputStream(file); ServletOutputStream out = response.getOutputStream(); int len=0; byte [] buf=new byte[1024]; while((len=in.read(buf))!=-1){ out.write(buf, 0, len); } in.close(); } }資料庫
create database upload_download_exercise; use upload_download_exercise; create table upfiles( id varchar(100), //使用UUID生成uuidname varchar(255),//uuid加上原來的文件名filename varchar(100),//真實文件名savepath varchar(255),//保存路徑uploadtime timestamp,//上傳時間description varchar(255),//描述username varchar(10) 上傳人);
以上所述是小編給大家分享的JAVA使用commos-fileupload實現文件上傳與下載的相關內容，希望對大家有所幫助。