本人闲来无事,写了个servlet,实现上传下载功能。启动服务后,可以在一个局域网内当一个小小的文件服务器。
一、准备工作
下载两个jar包:
commons-fileupload-1.3.1.jar
commons-io-2.2.jar
二、创建一个web工程
我的工程名叫:z-upload
三、配置web.xml
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<? xml version = "1.0" encoding = "UTF-8" ?>
< web-app xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
xmlns = "http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation = "http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
id = "WebApp_ID" version = "3.0" >
< display-name >z-upload</ display-name >
< servlet >
< servlet-name >UploadService</ servlet-name >
< servlet-class >com.syz.servlet.UploadService</ servlet-class >
</ servlet >
< servlet-mapping >
< servlet-name >UploadService</ servlet-name >
< url-pattern >/*</ url-pattern >
</ servlet-mapping >
</ web-app >
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从以上配置可以看出,我的servlet类是UploadService,匹配的url是/*,意思是匹配所有访问url。
四、写servlet类
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package com.syz.servlet;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import javax.servlet.ServletContext;
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.ProgressListener;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
public class UploadService extends HttpServlet {
public static final String LIST = "/list" ;
public static final String FORM = "/form" ;
public static final String HANDLE = "/handle" ;
public static final String DOWNLOAD = "/download" ;
public static final String DELETE = "/delete" ;
public static final String UPLOAD_DIR = "/upload" ;
private static final long serialVersionUID = 2170797039752860765L;
public void execute(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
System.out.println( "execute..." );
System.out.println( "------------begin---------------" );
req.setCharacterEncoding( "UTF-8" );
String host = req.getRemoteHost();
System.out.println( "host:" + host);
String uri = req.getRequestURI();
System.out.println( "uri:" + uri);
ServletContext servletContext = this .getServletConfig()
.getServletContext();
// 上传文件的基本路径
String basePath = servletContext.getRealPath(UPLOAD_DIR);
// 上下文路径
String contextPath = servletContext.getContextPath();
System.out.println( "contextPath:" + contextPath);
// 截取上下文之后的路径
String action = uri.substring(contextPath.length());
System.out.println( "action:" + action);
// 依据action不同进行不同的处理
if (action.equals(FORM)) {
form(contextPath, resp);
}
else if (action.equals(HANDLE)) {
boolean isMultipart = ServletFileUpload.isMultipartContent(req);
System.out.println( "isMultipart:" + isMultipart);
if (!isMultipart) {
return ;
}
DiskFileItemFactory factory = new DiskFileItemFactory();
File repository = (File) servletContext
.getAttribute(ServletContext.TEMPDIR);
System.out.println( "repository:" + repository.getAbsolutePath());
System.out.println( "basePath:" + basePath);
factory.setSizeThreshold( 1024 * 100 );
factory.setRepository(repository);
ServletFileUpload upload = new ServletFileUpload(factory);
// 创建监听
ProgressListener progressListener = new ProgressListener() {
public void update( long pBytesRead, long pContentLength,
int pItems) {
System.out.println( "当前文件大小:" + pContentLength + "\t已经处理:"
+ pBytesRead);
}
};
upload.setProgressListener(progressListener);
List<FileItem> items = null ;
try {
items = upload.parseRequest(req);
System.out.println( "items size:" + items.size());
Iterator<FileItem> ite = items.iterator();
while (ite.hasNext()){
FileItem item = ite.next();
if (item.isFormField()){
// handle FormField
} else {
// handle file
String fieldName = item.getFieldName();
String fileName = item.getName();
fileName = fileName.substring(
fileName.lastIndexOf(File.separator) + 1 );
String contentType = item.getContentType();
boolean isInMemory = item.isInMemory();
long sizeInBytes = item.getSize();
System.out.println(fieldName + "\t" + fileName + "\t"
+ contentType + "\t" + isInMemory + "\t"
+ sizeInBytes);
File file = new File(
basePath + "/" + fileName + "_" + getSuffix());
// item.write(file);
InputStream in = item.getInputStream();
OutputStream out = new FileOutputStream(file);
byte [] b = new byte [ 1024 ];
int n = 0 ;
while ((n = in.read(b)) != - 1 ) {
out.write(b, 0 , n);
}
out.flush();
in.close();
out.close();
}
}
// 处理完后重定向到文件列表页面
String href1 = contextPath + LIST;
resp.sendRedirect(href1);
}
catch (FileUploadException e) {
e.printStackTrace();
}
catch (Exception e) {
e.printStackTrace();
}
}
else if (action.equals(LIST)) {
list(contextPath, basePath, resp);
}
else if (action.equals(DOWNLOAD)) {
String id = req.getParameter( "id" );
System.out.println( "id:" + id);
if (id == null ) {
return ;
}
File file = new File(basePath);
File[] list = file.listFiles();
int len = list.length;
boolean flag = false ;
for ( int i = 0 ; i < len; i++) {
File f = list[i];
String fn = f.getName();
if (f.isFile() && fn.lastIndexOf( "_" ) > - 1 ) {
String fid = fn.substring(fn.lastIndexOf( "_" ));
if (id.equals(fid)) {
download(f, resp);
flag = true ;
break ;
}
}
}
if (!flag) {
notfound(contextPath, resp);
}
}
else if (action.equals(DELETE)) {
String id = req.getParameter( "id" );
System.out.println( "id:" + id);
if (id == null ) {
return ;
}
File file = new File(basePath);
File[] list = file.listFiles();
int len = list.length;
boolean flag = false ;
for ( int i = 0 ; i < len; i++) {
File f = list[i];
String fn = f.getName();
if (f.isFile() && fn.lastIndexOf( "_" ) > - 1 ) {
String fid = fn.substring(fn.lastIndexOf( "_" ));
if (id.equals(fid)) {
f.delete();
flag = true ;
break ;
}
}
}
if (flag) {
// 处理完后重定向到文件列表页面
String href1 = contextPath + LIST;
resp.sendRedirect(href1);
}
else {
notfound(contextPath, resp);
}
}
else {
show404(contextPath, resp);
}
System.out.println( "------------end---------------" );
}
private void show404(String contextPath, HttpServletResponse resp)
throws IOException {
resp.setContentType( "text/html;charset=utf-8" );
PrintWriter out = resp.getWriter();
String href1 = contextPath + LIST;
out.write( "<html>" );
out.write( "<head><title>404</title></thead>" );
out.write( "<body>" );
out.write( "<b>您所访问的页面不存在!<a href='" + href1 + "'>点击</a>返回文件列表</b>" );
out.write( "</body>" );
out.write( "</html>" );
out.close();
}
private void form(String contextPath, HttpServletResponse resp)
throws IOException {
resp.setContentType( "text/html;charset=utf-8" );
PrintWriter out = resp.getWriter();
String href1 = contextPath + LIST;
out.write( "<html>" );
out.write( "<head><title>form</title></thead>" );
out.write( "<body>" );
out.write( "<b><a href='" + href1 + "'>点击</a>返回文件列表</b>" );
out.write(
"<form action='handle' method='post' enctype='multipart/form-data' style='margin-top:20px;'>" );
out.write( "<input name='file' type='file'/><br>" );
out.write( "<input type='submit' value='上传'/><br>" );
out.write( "</form>" );
out.write( "</body>" );
out.write( "</html>" );
out.close();
}
private void notfound(String contextPath, HttpServletResponse resp)
throws IOException {
resp.setContentType( "text/html;charset=utf-8" );
PrintWriter out = resp.getWriter();
String href1 = contextPath + LIST;
out.write( "<html><body><b>操作失败!文件不存在或文件已经被删除!<a href='" + href1
+ "'>点击</a>返回文件列表</b></body></html>" );
out.close();
}
private void download(File f, HttpServletResponse resp)
throws IOException {
String fn = f.getName();
String fileName = fn.substring( 0 , fn.lastIndexOf( "_" ));
System.out.println( "fileName:" + fileName);
resp.reset();
resp.setContentType( "application/octet-stream" );
String encodingFilename = new String(fileName.getBytes( "GBK" ),
"ISO8859-1" );
System.out.println( "encodingFilename:" + encodingFilename);
resp.setHeader( "content-disposition" ,
"attachment;filename=" + encodingFilename);
InputStream in = new FileInputStream(f);
OutputStream out = resp.getOutputStream();
byte [] b = new byte [ 1024 ];
int n = 0 ;
while ((n = in.read(b)) != - 1 ) {
out.write(b, 0 , n);
}
out.flush();
in.close();
out.close();
}
private void list(String contextPath, String basePath,
HttpServletResponse resp)
throws IOException {
String href_u = contextPath + FORM;
resp.setContentType( "text/html;charset=utf-8" );
PrintWriter out = resp.getWriter();
out.write( "<html>" );
out.write( "<head><title>list</title></thead>" );
out.write( "<body>" );
out.write( "<b>我要<a href='" + href_u + "'>上传</a></b><br>" );
out.write(
"<table border='1' style='border-collapse:collapse;width:100%;margin-top:20px;'>" );
out.write( "<thead>" );
out.write( "<tr>" );
out.write( "<th>序号</th><th>文件名</th><th>操作</th>" );
out.write( "</tr>" );
out.write( "</thead>" );
out.write( "<tbody>" );
File file = new File(basePath);
File[] list = file.listFiles();
System.out
.println( "basePath:" + basePath + "\tlist.size:" + list.length);
int len = list.length;
int no = 1 ;
for ( int i = 0 ; i < len; i++) {
File f = list[i];
System.out.println(i + "\t" + f.getName());
String fn = f.getName();
if (f.isFile() && fn.lastIndexOf( "_" ) > - 1 ) {
String filename = fn.substring( 0 , fn.lastIndexOf( "_" ));
String id = fn.substring(fn.lastIndexOf( "_" ));
String href1 = contextPath + DOWNLOAD + "?id=" + id;
String href2 = contextPath + DELETE + "?id=" + id;
StringBuilder sb = new StringBuilder();
sb.append( "<tr>" );
sb.append( "<td>" );
sb.append(no++);
sb.append( "</td>" );
sb.append( "<td>" );
sb.append(filename);
sb.append( "</td>" );
sb.append( "<td>" );
sb.append( "<a href='" );
sb.append(href1);
sb.append( "'>下载</a> <a href='" );
sb.append(href2);
sb.append( "' onclick='return confirm(\"您确定要删除吗?\");'>删除</a>" );
sb.append( "</td>" );
sb.append( "</tr>" );
out.write(sb.toString());
}
}
out.write( "</tbody>" );
out.write( "</table>" );
out.write( "</body>" );
out.write( "</html>" );
out.close();
}
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
System.out.println( "doGet..." );
execute(req, resp);
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
System.out.println( "doPost..." );
execute(req, resp);
}
private String getSuffix() {
Date date = new Date();
SimpleDateFormat sdf = new SimpleDateFormat( "yyyyMMddHHmmssSSS" );
String suffix = sdf.format(date);
return suffix;
}
}
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其实UploadService类可以直接实现service方法,而不用实现doGet、doPost方法。
以上servlet我也不想多解释什么,自己看代码吧。
五、效果图
1.项目结构图
2.404页面
/*会匹配所有包括空字符,所以图片中的路径会匹配,在UploadService中的if判断中出现在else中,因为此时的action是空字符。
3.文件列表页面
4.上传表单页面
5.下载
6.删除
7.文件找不到,如果你点删除时,文件在服务器上已经不存在,那么会进入此页面
8.打包的源码工程和war包
其中z-upload是eclipse源码工程,z-upload.war是打好的war包
全工程就两个jar包,一个web.xml和一个servlet类,可以自己从文章中拷贝过去测试一下,如果是懒人,可以下载
http://download.csdn.net/detail/yunsyz/9569680,特别提醒,下载要1分哦。
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。