使用commons-fileupload上传文件到服务器

最新推荐文章于 2021-08-06 09:39:45 发布

闲蛋小超人

最新推荐文章于 2021-08-06 09:39:45 发布

阅读量663

点赞数

转自http://blog.youkuaiyun.com/lcyong_/article/details/70227161

需要的jar

commons-fileupload-1.3.2

commons-io-1.4

servlet-api

特别注意commons-fileupload使用的时候必须和commons-io一起, 注意版本,其他版本容易报错

1 新建project并导入jar包

2 新建jsp文件index.jsp如下:

[html] view plain copy

print ?

<%@ page language=“java” import=“java.util.*” pageEncoding=“UTF-8”%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+”://”+request.getServerName()+”:”+request.getServerPort()+path+”/”;
%>
<!DOCTYPE HTML >
<html>
<head>
<base href=“<%=basePath%>”>
<title>文件上传</title>
<script type=“text/javascript” language=“JavaScript”>
function prom() {
window.open(“upload.jsp”,”_blank”,”height=400,width=500“)
}
</script>
</head>
<body>
<button value=“上传文件”></button>
<input type=“button” value=“upload” onclick=“prom()”/>
</body>
</html>

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML >
<html>
  <head>
    <base href="<%=basePath%>">
    <title>文件上传</title>
      <script type="text/javascript" language="JavaScript">
          function prom() {
              window.open("upload.jsp","_blank","height=400,width=500")

          }
      </script>
  </head>
  <body>
  <button value="上传文件"></button>
  <input type="button" value="upload" οnclick="prom()"/>
  </body>
</html>

3 点击上传文件的时候弹窗出对话框新建jsp文件upload.jsp

[html] view plain copy

print ?

<%
String path = request.getContextPath();
String basePath = request.getScheme()+”://”+request.getServerName()+”:”+request.getServerPort()+path+”/”;
%>
<base href=“<%=basePath%>”>
<form method=“post” action=“UploadServlet” enctype=“multipart/form-data”>
<table width=“400” height=“200”>
<tr>
<td height=“20”></td>
</tr>
<tr>
<td height=“20”></td>
</tr>
<tr>
<td align=“center”>选择上传文件：(文件大小不要超过2MB)</td>
</tr>
<tr>
<td align=“center”> <input type=“file” name=“file1” size=“50” value=“选择文件”></td>
</tr>
<tr>
<td align=“center”> <input type=“submit” value=“开始上传”></td>
</tr>
<tr>
<td height=“40”></td>
</tr>
</table>
</form>
结果:<%=request.getAttribute(“result”)%>

<%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<base href="<%=basePath%>">
<form method="post" action="UploadServlet" enctype="multipart/form-data">
    <table width="400" height="200">
        <tr>
            <td height="20"></td>
        </tr>
        <tr>
            <td height="20"></td>
        </tr>
        <tr>
            <td align="center">选择上传文件：(文件大小不要超过2MB)</td>
        </tr>
        <tr>
            <td align="center"> <input type="file" name="file1" size="50" value="选择文件"></td>
        </tr>
        <tr>
            <td align="center"> <input type="submit" value="开始上传"></td>

        </tr>
        <tr>
            <td height="40"></td>
        </tr>
    </table>
</form>
结果:<%=request.getAttribute("result")%>

4 在新建一个servlet UploadServlet

[java] view plain copy

print ?

package com.lh.servlet;
import java.io.*;
import java.util.*;
import org.apache.commons.fileupload.*;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import javax.servlet.*;
import javax.servlet.http.*;
public class UploadServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding(”UTF-8”);
String Path=getServletContext().getRealPath(”/”)+“upload”; //定义上传文件的地址
System.out.print(Path);
File folder = new File(Path);
if(!folder.exists())
folder.mkdirs();
String message=null;
if(ServletFileUpload.isMultipartContent(request)){ //判断是否获取的是文件
DiskFileItemFactory disk=new DiskFileItemFactory();
disk.setSizeThreshold(20*1024); //设置内存可存字节数
disk.setRepository(disk.getRepository()); //设置临时文件目录
ServletFileUpload up=new ServletFileUpload(disk);
int maxsize=200*1024*1024;
List list=null;
try{
System.err.print(”—————–”);
list=up.parseRequest(request); //获取上传列表
}
catch(Exception e){
e.printStackTrace();
}
Iterator i=list.iterator(); //创建列表的迭代器
while(i.hasNext()){
FileItem fm=(FileItem)i.next(); //遍历列表
if(!fm.isFormField()){
String fname=fm.getName(); //获取文件名
String filePath =fm.getName(); //获取文件全路径名
String fileName=”“;
int startIndex = filePath.lastIndexOf(“\\”);
if(startIndex!=-1){ //对文件名进行截取
fileName = filePath.substring(startIndex+1);
}else{
fileName=filePath;
}
if(fm.getSize()>maxsize){
message=”文件太大了，不要超过200MB”;
break;
}
String fileSize=new Long(fm.getSize()).toString();
if((fname==null)||(fname.equals(“”))&&(fileSize.equals(“0”))){
message=”文件名不能为空，文件大小也不能为零！”;
break;
}
File saveFile=new File(Path,fileName);
try{
fm.write(saveFile);//向文件中写入数据
message=”文件上传成功！”;
}
catch(Exception e1){
e1.printStackTrace();
}
}
}
}
request.setAttribute(”result”,message);
RequestDispatcher rd=request.getRequestDispatcher(”upload.jsp”);
rd.forward(request, response);
}
public void init(ServletConfig config) throws ServletException {
super.init(config);
}
}

package com.lh.servlet;

import java.io.*;
import java.util.*;
import org.apache.commons.fileupload.*;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import javax.servlet.*;
import javax.servlet.http.*;

public class UploadServlet extends HttpServlet {

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("UTF-8");
        String Path=getServletContext().getRealPath("/")+"upload";          //定义上传文件的地址

        System.out.print(Path);
        File folder = new File(Path);
        if(!folder.exists())
            folder.mkdirs();
        String message=null;
        if(ServletFileUpload.isMultipartContent(request)){  //判断是否获取的是文件
            DiskFileItemFactory disk=new DiskFileItemFactory();
            disk.setSizeThreshold(20*1024);                 //设置内存可存字节数
            disk.setRepository(disk.getRepository());       //设置临时文件目录
            ServletFileUpload up=new ServletFileUpload(disk);
            int maxsize=200*1024*1024;
            List list=null;
            try{
                System.err.print("-----------------");
                list=up.parseRequest(request);              //获取上传列表
            }
            catch(Exception e){
                e.printStackTrace();
            }
            Iterator i=list.iterator();                     //创建列表的迭代器
            while(i.hasNext()){
                FileItem fm=(FileItem)i.next();             //遍历列表
                if(!fm.isFormField()){
                    String fname=fm.getName();              //获取文件名
                    String filePath =fm.getName();  //获取文件全路径名
                    String fileName="";
                    int startIndex = filePath.lastIndexOf("\\");
                    if(startIndex!=-1){                     //对文件名进行截取
                        fileName = filePath.substring(startIndex+1);
                    }else{
                        fileName=filePath;
                    }
                    if(fm.getSize()>maxsize){
                        message="文件太大了，不要超过200MB";
                        break;
                    }
                    String fileSize=new Long(fm.getSize()).toString();
                    if((fname==null)||(fname.equals(""))&&(fileSize.equals("0"))){
                        message="文件名不能为空，文件大小也不能为零！";
                        break;
                    }
                    File saveFile=new File(Path,fileName);
                    try{
                        fm.write(saveFile);//向文件中写入数据

                        message="文件上传成功！";

                    }
                    catch(Exception e1){
                        e1.printStackTrace();
                    }
                }
            }
        }
        request.setAttribute("result",message);
        RequestDispatcher rd=request.getRequestDispatcher("upload.jsp");
        rd.forward(request, response);

    }

    public void init(ServletConfig config) throws ServletException {
        super.init(config);
    }

}

5 在web.xml文件中配置如下:

[html] view plain copy

print ?

<servlet>
<description>UploadServlet</description>
<display-name>UploadServlet</display-name>
<servlet-name>UploadServlet</servlet-name>
<servlet-class>com.lh.servlet.UploadServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UploadServlet</servlet-name>
<url-pattern>/UploadServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>

 <servlet>
    <description>UploadServlet</description>
    <display-name>UploadServlet</display-name>
    <servlet-name>UploadServlet</servlet-name>
    <servlet-class>com.lh.servlet.UploadServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>UploadServlet</servlet-name>
    <url-pattern>/UploadServlet</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>