java基于servlet编写上传下载功能 类似文件服务器

java基于servlet编写上传下载功能 类似文件服务器

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

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">

z-upload

UploadService

com.syz.servlet.UploadService

UploadService

/*

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">

z-upload

UploadService

com.syz.servlet.UploadService

UploadService

/*

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

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.getAbsolutePatmZIFVScwPph());

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 items = null;

try {

items = upload.parseRequest(req);

System.out.println("items size:" + items.size());

Iterator 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.getNmZIFVScwPpame();

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("");

out.write("

out.write("

out.write("您所访问的页面不存在！点击返回文件列表");

out.write("");

out.write("");

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("");

out.write("

out.write("

out.write("点击返回文件列表");

out.write(

"

out.write("
");

out.write("
");

out.write("

out.write("");

out.write("");

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("

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("");

out.write("

out.write("

out.write("我要上传
");

out.write(

"

out.write("");

out.write("

out.write("

out.write("

out.write("

out.write("

out.write("

out.write("

out.write("

out.write("

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("

sb.append("

sb.append(no++);

sb.append("

sb.append("

sb.append(filename);

sb.append("

sb.append("

sb.append("下载 删除");

sb.append("

sb.append("

out.write(sb.toString());

}

}

out.write("

out.write("

out.write("");

out.write("");

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;

}

}

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。

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。