java实现文件上传下载
有没有那本书讲过如何用java实现文件上传下载啊？
[解决办法]
[code=Java][/code]import java.io.FileInputStream;
import java.io.OutputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class FileDownload extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response) {
try {
String fname = "test.xls";
response.setCharacterEncoding("UTF-8");
fname = java.net.URLEncoder.encode(fname, "UTF-8");
response.setHeader("Content-Disposition", "attachment; filename="+fname);
response.setContentType("application/msexcel");// 定义输出类型
} catch (Exception e) {
System.out.println(e);
}
}
}
//上面是下载用的servlet
[code=Java][/code]import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
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.FileItemFactory;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
public class FileUpload extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
if (isMultipart) {
FileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload upload = new ServletFileUpload(factory);
Iterator items;
try {
items = upload.parseRequest(request).iterator();
while (items.hasNext()) {
FileItem item = (FileItem) items.next();
if (!item.isFormField()) {
//取出上传文件的文件名称
String name = item.getName();
String fileName = name.substring(name.lastIndexOf('\\')+1,name.length());
String path = request.getRealPath("file")+File.separatorChar+fileName;
//上传文件
File uploadedFile = new File(path);
item.write(uploadedFile);
//打印上传成功信息
response.setContentType("text/html");
response.setCharacterEncoding("gb2312");
PrintWriter out = response.getWriter();
out.print("<font size='2'>上传的文件为："+name+"<br>");
out.print("保存的地址为："+path+"</font>");
}
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
// 上面是 上传的servlet
希望能给楼主一点帮助，我和你一样 也是在学习中
[解决办法]
文件上传类:MoqUploadBean.java
package net.moq.www;
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
/**
*
* Title: 文件上传类
* Description: 既能对文件进行上传,又能取得输入框的值,最多可同时上传255个文件
* Copyright: Copyright (c) 2002
* Company: Tekson
* @author 莫琼
* @version 1.0
*/
public class MoqUploadBean {
private String[] sourceFile = new String[255]; //源文件名
private String[] suffix = new String[255]; //文件后缀名
private String canSuffix = ".gif.jpg.jpeg.png"; //可上传的文件后缀名
private String objectPath = "c:/"; //目标文件目录
private String[] objectFileName = new String[255]; //目标文件名
private ServletInputStream sis = null; //输入流
private String[] description = new String[255]; //描述状态
private long size = 100 * 1024; //限制大小
private int count = 0; //已传输文件数目
private byte[] b = new byte[4096]; //字节流存放数组
private boolean successful = true;
private Hashtable fields = new Hashtable();
public MoqUploadBean() {
}
//设置上传文件的后缀名
public void setSuffix(String canSuffix) {
this.canSuffix = canSuffix;
}
//设置文件保存路径
public void setObjectPath(String objectPath) {
this.objectPath = objectPath;
}
//设置文件保存路径
public void setSize(long maxSize) {
this.size = maxSize;
}
//文件上传处理程序
public void setSourceFile(HttpServletRequest request) throws IOException {
sis = request.getInputStream();
int a = 0;
int k = 0;
String s = "";
while ( (a = sis.readLine(b, 0, b.length)) != -1) {
s = new String(b, 0, a);
if ( (k = s.indexOf("filename=\"")) != -1) {
// 取得文件数据
s = s.substring(k + 10);
k = s.indexOf("\"");
s = s.substring(0, k);
sourceFile[count] = s;
k = s.lastIndexOf(".");
suffix[count] = s.substring(k + 1);
if (canTransfer(count)) {
transferFile(count);
}
++count;
} else if ( (k = s.indexOf("name=\"")) != -1) {
// 普通表单输入元素，获取输入元素名字
String fieldName = s.substring(k+6, s.length()-3);
sis.readLine(b, 0, b.length);
StringBuffer fieldValue = new StringBuffer(b.length);
while ( (a = sis.readLine(b, 0, b.length)) != -1) {
s = new String(b, 0, a-2);
if ( (b[0] == 45) && (b[1] == 45) && (b[2] == 45) && (b[3] == 45) && (b[4] == 45)) {
break;
} else {
fieldValue.append(s);
}
}
fields.put(fieldName, fieldValue.toString());
}
if (!successful)
break;
}
}
//取得表单元素值
public String getFieldValue(String fieldName) {
if (fields == null || fieldName == null) {
return null;
}
return (String) fields.get(fieldName);
}
//取得上传文件数
public int getCount() {
return count;
}
//取得目标路径
public String getObjectPath() {
return objectPath;
}
//取得源文件名
public String[] getSourceFile() {
return sourceFile;
}
//取得目标文件名
public String[] getObjectFileName() {
return objectFileName;
}
//取得上传状态描述
public String[] getDescription() {
return description;
}
//判断上传文件的类型
private boolean canTransfer(int i) {
suffix[i] = suffix[i].toLowerCase();
//这个是用来传图片的，各位可以把后缀名改掉或者不要这个条件
if (sourceFile[i].equals("") || (!(canSuffix.indexOf("."+suffix[i])>=0))) {
description[i] = "ERR: File suffix is wrong.";
return false;
}
else {
return true;
}
}
//上传文件转换
private void transferFile(int i) {
String x = Long.toString(new java.util.Date().getTime());
try {
objectFileName[i] = x + "." + suffix[i];
FileOutputStream out = new FileOutputStream(objectPath + objectFileName[i]);
int a = 0;
int k = 0;
long hastransfered = 0; //标示已经传输的字节数
String s = "";
while ( (a = sis.readLine(b, 0, b.length)) != -1) {
s = new String(b, 0, a);
if ( (k = s.indexOf("Content-Type:")) != -1) {
break;
}
}
sis.readLine(b, 0, b.length);
while ( (a = sis.readLine(b, 0, b.length)) != -1) {
s = new String(b, 0, a);
if ( (b[0] == 45) && (b[1] == 45) && (b[2] == 45) && (b[3] == 45) && (b[4] == 45)) {
break;
}
out.write(b, 0, a);
hastransfered += a;
if (hastransfered >= size) {
description[count] = "ERR: The file " + sourceFile[count] +
" is too large to transfer. The whole process is interrupted.";
successful = false;
break;
}
}
if (successful) {
description[count] = "Right: The file " + sourceFile[count] +
" has been transfered successfully.";
}
out.close();
if (!successful) {
sis.close();
File tmp = new File(objectPath + objectFileName[count]);
tmp.delete();
}
}
catch (IOException ioe) {
description[i] = ioe.toString();
}
}
public static void main(String[] args) {
System.out.println("Test OK");
}
}
