自学java，选择从简单的javaweb入手了。
读了网上某位大神的细致文章，了解后自己写了这篇上传下载的，加上了自己一部分的理解注释。
算是入门篇吧。大致完成了任务，比较粗糙。
fileHanderServlet.java （文件上传处理）
1 package up.file.Servletfile;
2
3 import java.io.File;
4 import java.io.FileInputStream;
5 import java.io.FileOutputStream;
6 import java.io.IOException;
7 import java.io.InputStream;
8 import java.util.List;
9 import java.util.UUID;
10
11 import javax.servlet.ServletException;
12 import javax.servlet.annotation.WebServlet;
13 import javax.servlet.http.HttpServlet;
14 import javax.servlet.http.HttpServletRequest;
15 import javax.servlet.http.HttpServletResponse;
16
17 import org.apache.commons.fileupload.FileItem;
18 import org.apache.commons.fileupload.FileUploadBase;
19 import org.apache.commons.fileupload.FileUploadException;
20 import org.apache.commons.fileupload.ProgressListener;
21 import org.apache.commons.fileupload.disk.DiskFileItemFactory;
22 import org.apache.commons.fileupload.servlet.ServletFileUpload;
23
24 /**
25 * Servlet implementation class fileHandleServlet
26 */
27 @WebServlet("/fileHandleServlet")
28 public class fileHandleServlet extends HttpServlet {
29 private static final long serialVersionUID = 1L;
30
31 /**
32 * @see HttpServlet#HttpServlet()
33 */
34 public fileHandleServlet() {
35 super();
36 // TODO Auto-generated constructor stub
37 }
38
39 /**
40 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
41 */
42 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
43 //获取上传目录
44 String filePath=this.getServletContext().getRealPath("/WEB-INF/upload");
45 //设置临时上传目录
46 String tempPath=this.getServletContext().getRealPath("/WEB-INF/temp");
47 //设置message消息
48 String message="";
49 //System.out.println("filePath:="+filePath);
50 //将文件目录转为文件
51 File file=new File(filePath);
52 //将临时文件目录转为文件
53 File tempfile=new File(tempPath);
54 //System.out.println("file:="+file);
55 //isDirectory()文件夹是否为文件，exists()是否存在
56 if(!file.exists()&&!file.isDirectory())
57 {
58 System.out.println("该文件不存在，重新创建！");
59 file.mkdirs();
60 }
61 //判断临时文件目录是否存在
62 if(!tempfile.exists()&&!tempfile.isDirectory())
63 {
64 System.out.println("该临时文件不存在，重新创建！");
65 tempfile.mkdirs();
66 }
67 //创建DiskDiskFileItemFactory工厂
68 DiskFileItemFactory factory=new DiskFileItemFactory();
69 //设置factory工厂的缓冲区大小
70 factory.setSizeThreshold(1024*1025*5);//1024字节*1024*5=5M
71 //设定临时上传文件目录
72 factory.setRepository(tempfile);
73 //创建文件上传解析器
74 ServletFileUpload upload=new ServletFileUpload(factory);
75 //设置字符
76 upload.setHeaderEncoding("UTF-8");
77 //判断上传的是普通表单还是带文件上传的表单
78 //isMultipartContent() 带文件上传的返回为true,普通表单为false
79 //System.out.println(ServletFileUpload.isMultipartContent(request));
80 //进度监听
81 upload.setProgressListener(
82 new ProgressListener(){
83 public void update(long pBytesRead,long pContentLength,int arg2){
84 System.out.println("文件大小为："+pContentLength+",当前已处理:"+pBytesRead+",arg2:="+arg2);
85 }
86 });
87
88 if(!ServletFileUpload.isMultipartContent(request))
89 {
90 return;
91 }
92 //System.out.println("获取打印:="+upload.parseRequest(request));
93 //将文件装入List数组类中
94 //设置单个文件上传最大值 1024*1024
95 upload.setFileSizeMax(1024*1024*10);
96 //设置上传文件总量大小
97 upload.setSizeMax(1024*1024*100);
98 try {
99 List<FileItem> filelist=upload.parseRequest(request);
100 //System.out.println("List:="+filelist);
101 //isFormFiled判断普通表单和FILE表单
102 for(FileItem item:filelist)
103 {
104 if(item.isFormField())
105 {
106 /*System.out.println("getFiledName():="+item.getFieldName());*/
107 String name=item.getFieldName();//获取jsp页面text上input名
108 String value=item.getString("UTF-8");//获取jsp页面text上的value值
109 System.out.println(name+"="+value);
110 }else
111 {
112 String filename=item.getName();//获取jsp传的文件名
113 int lenth=item.getFieldName().length();
114 System.out.println("lenth:="+lenth);
115 //System.out.println("hash:filename="+filename);
116 filename=unqueFilename(filename);
117 //hash打乱存储目录
118 filename=hashfile(filename,filePath);
119 //System.out.println("filename:="+filename);
120 if(filename.trim().equals("")&&filename==null)
121 {
122 continue;
123 }
124 //创建输入流和输出流，将文件写入到缓存空间
125 //在对文件进行存入的时候，设置输入流，并利用输入流将文件存入缓存区后，使用文件输出流FileOutputStream输出到文件中
126 filename=filename.substring(filename.lastIndexOf("\\")+1);
127 //每一个item创建一个输入流
128 InputStream in=item.getInputStream();
129 System.out.println("item.getInputStream:="+item.getInputStream());
130 System.out.println("item:="+item);
131 //每一个item创建一个文件输出流
132 //System.out.println("完整连接:="+filePath+"\\"+filename);
133 FileOutputStream out=new FileOutputStream(filePath+"\\"+filename);
134 //创建缓存区1024*1024*5=5m
135 byte buffer[]=new byte[1024*1024*5];
136 int len=0;
137 //将文件存入缓存区
138 //System.out.println("in.read值:="+in.read(buffer));
139 while((len=in.read(buffer))>0)
140 {
141 out.write(buffer,0,len); // 将指定 byte 数组中从偏移量 off 开始的 len 个字节写入此输出流
142 }
143 in.close();//关闭输入流
144 out.close();//关闭输出流
145 item.delete();//删除临时的文件
146 message="文件上传成功！";
147 }
148 }
149 }
150 catch(FileUploadBase.FileSizeLimitExceededException e){
151 message="单个文件上传超出限制！";
152 String filename=e.getFileName();
153 //System.out.println("抛出file：="+e.getFileName());
154 //System.out.println("抛出field：="+e.getFieldName());
155 byte buffer[]=new byte[1024*1024*10];
156 //checkFilewrite(filename,filePath,buffer);
157 e.printStackTrace();
158 }
159 catch(FileUploadBase.SizeLimitExceededException e){
160 message="上传总数超出限制！";
161 e.printStackTrace();
162 }
163 catch (FileUploadException e) {
164 // TODO Auto-generated catch block
165 message="文件上传失败";
166 e.printStackTrace();
167 }
168 request.setAttribute("message", message);
169 request.getRequestDispatcher("/message.jsp").forward(request, response);
170 }
171
172 //获取唯一文件名
173 public String unqueFilename(String filename){
174 return UUID.randomUUID().toString()+"_"+filename;
175 }
176 //hash打乱存储目录
177 public String hashfile(String filename,String filePath){
178 int hashcode=filename.hashCode();
179 int dir1=hashcode&0xf;
180 int dir2=(hashcode&0xf0)>>4;
181 String dir=filePath+"\\"+dir1+"\\"+dir2+"\\"+filename;
182 //System.out.println("dir1:="+dir1+"dir2:="+dir2+"dir:="+dir);
183 return dir;
184 }
185 //文件写入缓存区间
186 public void checkFilewrite(String filename,String filePath,byte buffer[]){
187 int len=0;
188 InputStream ip;
189 FileOutputStream op;
190 try {
191 ip=new FileInputStream(filePath+"\\"+filename);
192 op=new FileOutputStream(filePath+"\\"+filename);
193 while((len=ip.read(buffer))>0){
194 op.write(buffer,0,len);
195 }
196 } catch (IOException e) {
197 // TODO Auto-generated catch block
198 e.printStackTrace();
199 }
200
201 }
202
203 /**
204 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
205 */
206 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
207 // TODO Auto-generated method stub
208 doGet(request, response);
209 }
210
211 }
fileListServlet.java (文件下载页面处理)
1 package up.file.Servletfile;
2
3 import java.io.File;
4 import java.io.IOException;
5 import java.util.HashMap;
6 import java.util.Map;
7
8 import javax.servlet.ServletException;
9 import javax.servlet.annotation.WebServlet;
10 import javax.servlet.http.HttpServlet;
11 import javax.servlet.http.HttpServletRequest;
12 import javax.servlet.http.HttpServletResponse;
13
14 /**
15 * Servlet implementation class fileListServlet
16 */
17 @WebServlet("/fileListServlet")
18 public class fileListServlet extends HttpServlet {
19 private static final long serialVersionUID = 1L;
20
21 /**
22 * @see HttpServlet#HttpServlet()
23 */
24 public fileListServlet() {
25 super();
26 // TODO Auto-generated constructor stub
27 }
28
29 /**
30 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
31 */
32 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
33 // TODO Auto-generated method stub
34 //response.getWriter().append("Served at: ").append(request.getContextPath());
35 //获取文件上传目录
36 String filePath=this.getServletContext().getRealPath("/WEB-INF/upload");
37 //上传目录转为文件
38 File file=new File(filePath);
39 //通过Map接口实现存储下载文件
40 Map<String,String> filemap=new HashMap<String,String>();
41 filelist(file,filemap);
42
43 request.setAttribute("filemap", filemap);
44 request.getRequestDispatcher("/listFile.jsp").forward(request, response);
45
46 }
47
48 public void filelist(File file,Map<String,String> map){
49 //如果file不是文件，是目录，则遍历该目录下所有的文件
50 if(!file.isFile()){
51 File files[]=file.listFiles();
52 for(File item:files){
53 filelist(item,map);
54 }
55 }else{
56 //如果file是文件，则取出uuid后的真实文件名，存入map中
57 String realname=file.getName().substring(file.getName().indexOf("_")+1);
58 String filename=file.getName();
59 System.out.println("realname:="+realname+"filename:="+filename);
60 map.put(filename, realname);
61 }
62 }
63
64 /**
65 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
66 */
67 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
68 // TODO Auto-generated method stub
69 doGet(request, response);
70 }
71
72 }
downLoadServlet.java (文件下载处理)
1 package up.file.Servletfile;
2
3 import java.io.File;
4 import java.io.FileInputStream;
5 import java.io.FileOutputStream;
6 import java.io.IOException;
7 import java.io.OutputStream;
8 import java.net.URLEncoder;
9
10 import javax.servlet.ServletException;
11 import javax.servlet.annotation.WebServlet;
12 import javax.servlet.http.HttpServlet;
13 import javax.servlet.http.HttpServletRequest;
14 import javax.servlet.http.HttpServletResponse;
15
16 /**
17 * Servlet implementation class DownLoadServlet
18 */
19 @WebServlet("/DownLoadServlet")
20 public class DownLoadServlet extends HttpServlet {
21 private static final long serialVersionUID = 1L;
22
23 /**
24 * @see HttpServlet#HttpServlet()
25 */
26 public DownLoadServlet() {
27 super();
28 // TODO Auto-generated constructor stub
29 }
30
31 /**
32 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
33 */
34 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
35 // TODO Auto-generated method stub
36 //response.getWriter().append("Served at: ").append(request.getContextPath());
37 //获取上传文件名
38 String filename=request.getParameter("filename");
39 String message="";
40 //取出UUID后获取真实文件名
41 String realname=filename.substring(filename.lastIndexOf("_")+1);
42 //设置浏览器相应头
43 response.setHeader("content-disposition", "attachment;filename="+URLEncoder.encode(realname,"UTF-8"));
44 //获取上传目录
45 String filePath=this.getServletContext().getRealPath("/WEB-INF/upload");
46 //获取该文件
47 File file=new File(filePath+"\\"+filename);
48 //判断文件是否存在
49 if(!file.exists()){
50 message="该文件已经被删除！";
51 request.setAttribute("message", message);
52 request.getRequestDispatcher("/message.jsp").forward(request, response);
53 }
54 //设置文件输入流，利用文件输入流，将需要下载的文件输入到文件输入流中，利用输出流读取存入缓存区的文件，然后输出
55 FileInputStream fileip=new FileInputStream(filePath+"\\"+filename);
56 OutputStream out=response.getOutputStream();
57 int len=0;
58 byte buffer[]=new byte[1024*1024];
59 while((len=fileip.read(buffer))>0){
60 out.write(buffer,0,len);
61 }
62
63 fileip.close();
64 out.close();
65 }
66
67 /**
68 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
69 */
70 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
71 // TODO Auto-generated method stub
72 doGet(request, response);
73 }
74
75 }
JSP现实采用了C标签
具体源码如下，注释比较消息，这里就不多解释了，有不对或者注释解释错误的地方，求各位指正，小弟初学java才一周。
源码：http://share.weiyun.com/f09e8aeffdae8167384def96fda3cb17
时间： 2024-11-10 08:16:28