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servlet類:
package cn.itcast.service;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
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;
/***
* 通過servlet上傳附件
* @author huawei
*
*/
public class HandleFileServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException{
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
String uri = request.getRequestURI();
uri = uri.substring(uri.lastIndexOf("/"), uri.lastIndexOf("."));
if(("/uploadfile").equals(uri)){
//設定臨時目錄
DiskFileItemFactory factory = new DiskFileItemFactory();
//factory.setSizeThreshold(1024*1024); //設定了1M的緩衝區,對於大文件需要通過創建臨時目錄來緩存
//factory.setRepository(new File("E:/temp")); //設置上傳文件的臨時目錄
//可以需要臨時目錄,也可以不需要
ServletFileUpload fileUpload = new ServletFileUpload(factory);
//限制上傳文件的大小
fileUpload.setSizeMax(10 * 1024 * 1024);
//實現進度監聽:需要實現對文件上傳進度的監聽,需要給FileUpload 對象添加 ProgressListener
fileUpload.setProgressListener(new ProgressListener() {
long num = 0;
@Override
public void update(long bytesRead, long contentLength, int items) {
long progress = bytesRead*100/contentLength;
if(progress == num)
return;
num = progress;
System.out.println("上傳進度: " + progress + "%");
//request.getSession().setAttribute("progress", progress);
/*try {
response.getWriter().write("上傳進度: " + progress + "%" + "<br/>");
} catch (IOException e) {
e.printStackTrace();
}*/
}
});
try {
@SuppressWarnings("unchecked")
List<FileItem> items = fileUpload.parseRequest(request);
for(FileItem item : items){
if(item.isFormField()){// 判斷是普通表單文件,還是文件流文件
System.out.println("表單參數名:" + item.getFieldName()
+ ",表單參數值:" + item.getString("UTF-8"));
}else{
PrintWriter out = response.getWriter();
if(item.getName() != null && !item.getName().equals("")){
out.write("上傳文件的大小:" + item.getSize() + "<br/>"); //上傳文件的大小:33403
out.write("上傳文件的類型:" + item.getContentType() + "<br/>"); //上傳文件的類型:image/x-png
//item.getName()返回上傳文件在客戶端的完整路徑名稱
String fileName = item.getName();
fileName = fileName.substring(fileName.lastIndexOf("\\")+1);
out.write("上傳文件的名稱:" + fileName); //上傳文件的名稱:mysql_to_java.png
}else{
out.write("沒有選擇上傳文件!");
}
}
}
} catch (FileUploadException e) {
e.printStackTrace();
}
}
}
}
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請求的jsp文件:
<%@ page contentType="text/html; charset=utf-8" language="java" import="java.sql.*" errorPage="" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html version="-//W3C//DTD HTML 4.01 Transitional//EN">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>文件上傳</title>
</head>
<body>
<form action="servlet/uploadfile.do" enctype="multipart/form-data" method="post">
<input type="file" value="file" name="file"/>
<br />
<input type="submit" value="submit" />
</form>
</body>
</html>
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web.xml
<servlet>
<servlet-name>uploadfile</servlet-name>
<servlet-class>cn.itcast.service.HandleFileServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>uploadfile</servlet-name>
<url-pattern>/servlet/uploadfile.do</url-pattern>
</servlet-mapping>
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主要使用的如下:
FileItem-------DiskFileItemFactory-----ServletFileUpload
作用:
FileItem 用來封裝表單中的元素和數據。
ServletFileUpload 處理表單數據,將數據封裝到 FileItem 對象中。
DiskFileItemFactory FileItem 對象的工廠,可以設定緩衝區大小和存放臨時文件目錄。
ServletFileUpload 處理上傳的文件的數據,優先保存在緩衝區,如果數據超過了緩衝區大小,則保存到硬盤上,存儲在DiskFileItemFactory指定目錄下的臨時文件。數據都接收完後,它再在從臨時文件中將數據寫入到上傳文件目錄下的指定文件中,並刪除臨時文件。
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api:
1. DiskFileItemFactory 對象
設置緩衝區大小,字節爲單位,默認爲10K,一般不用修改
factory.setSizeThreshold(1000);
設置臨時文件存放目錄
factory.setRepository(file);
2. ServletFileUpload 對象
判斷是否爲文件上傳表單
boolean b = upload.isMultipartContent(request);
解析request對象
List<FileItem> list = upload.parseRequest(request);
設置上傳文件的最大值
setFileSizeMax(long fileSizeMax)
設置上傳文件總量的最大值
setSizeMax(long sizeMax)
設置編碼格式
setHeaderEncoding(java.lang.String encoding)
註冊進度監聽器
setProgressListener(ProgressListener pListener)
3. FileItem 對象
獲得表單字段的屬性名
item.getFieldName();
獲得普通字段的值
item.getString(charsetName)
獲得文件上傳字段的文件名
item.getName()
獲得文件上傳的流
item.getInputStream()