Javaweb中最简单的文件上传

最简单的文件上传

1、在做之前需要导入的jar包组件:

commons-fileupload-1.2.1.jar、commons-io-2.0.jar(依赖包)

2、页面代码

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	<form action="simpleFileupload" 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>
注意:这里的enctype(编码类型)是“multipart/form-data”

3、servlet代码

package com.xiaojie.simpleFileupload;

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

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	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:\\linshi");//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 {
			// 1. 得到 FileItem 的集合 items
			List<FileItem> /* FileItem */items = upload.parseRequest(request);

			// 2. 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 e:\\files 目录下.
				else {
					String fileName = item.getName();
					long sizeInBytes = item.getSize();
					System.out.println(fileName);
					System.out.println(sizeInBytes);

					InputStream in = item.getInputStream();
					byte[] buffer = new byte[1024];
					int len = 0;

					fileName = "e:\\files\\" + fileName;//文件最终上传的位置
					System.out.println(fileName);
					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();
		}

	}
}
运行simpleFileupload.jsp文件(如下图)
选择好自己想要上传的文件后,在服务器的e盘下的files文件夹中就可以看到自己上传成功的文件了!!!


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