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
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.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 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.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("");
out.write("404 ");
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("form ");
out.write("");
out.write("点击返回文件列表");
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("操作失败！文件不存在或文件已经被删除！点击返回文件列表");
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("list ");
out.write("");
out.write("我要上传
");
out.write(
"");
out.write("");
out.write("");
out.write("序号 文件名 操作 ");
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。
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考高分网。
