文件上传-commons-fileupload组件

1.简单的jsp文件上传界面

<%@ page language="java" contentType="text/html; charset=UTF-8" 
 pageEncoding="UTF-8"%>  
<html>   
<body>  
<form action="servlet2/UploadServlet" method="post" enctype="multipart/form-data">  
    最简单的文件上传：<input type="file" name="fileupload"/>  
    描述：<input type="text" name="desc"/>  
<input type="submit" value="submit"/>  
</form>  
</body>  
</html>

2、UploadServlet.java

重点：1、2、3是主要核心代码

package servlet2;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

/**
 * Servlet implementation class UploadServlet
 */
//@WebServlet("/UploadServlet")
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");  
        response.setCharacterEncoding("utf-8");  
//1、创建一个DiskFileItemFactory工厂 
        DiskFileItemFactory factory = new DiskFileItemFactory();  
//2、创建一个文件上传解析器 
        ServletFileUpload upload = new ServletFileUpload(factory);  
//解决上传文件名的中文乱码 
        upload.setHeaderEncoding("UTF-8");   
        factory.setSizeThreshold(1024 * 500);//设置内存的临界值为500K 
        File linshi = new File("E:\\");//当超过500K的时候，存到一个临时文件夹中 
        factory.setRepository(linshi);  
        upload.setSizeMax(1024 * 1024 * 5);//设置上传的文件总的大小不能超过5M 
try {  
// 3. 得到 FileItem 的集合 items 
            List<FileItem> /* FileItem */items = upload.parseRequest(request);  

// 4. 遍历 items: 
for (FileItem item : items) {  
// 若是一个一般的表单域, 打印信息 
if (item.isFormField()) {  
                    String name = item.getFieldName();  
                    String value = item.getString("utf-8");  

                    System.out.println(name + ": " + value);  


                }  
// 若是文件域则把文件保存到 f:\\files 目录下. 
else {  
                    String fileName = item.getName();  
long sizeInBytes = item.getSize();  
                    System.out.println(fileName);  
                    System.out.println(sizeInBytes);  
//文字输入流读入
                    InputStream in = item.getInputStream();  
byte[] buffer = new byte[1024];  
int len = 0;  

                    fileName = "E:\\files";//文件最终上传的位置 
                    System.out.println(fileName);  
//文字输出流读取
                    OutputStream out = new FileOutputStream(fileName);  

while ((len = in.read(buffer)) != -1) {  
                        out.write(buffer, 0, len);  
                    }  

                    out.close();  
                    in.close();  
                }  
            }  

        } catch (FileUploadException e) {  
            e.printStackTrace();  
        }  
    }

}

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文件上传-commons-fileupload组件

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