【狂神說Java】JavaWeb-文件上傳

記錄一下，以免以下幾個包導錯

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;

源碼：

FileSerlvet類

package com.chen;

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

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;

/**
 * Servlet implementation class FileSerlvet
 */
public class FileSerlvet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		// response.getWriter().append("Served at: ").append(request.getContextPath());
		
		// 判斷上傳的文件普通表單還是帶文件的表單
		if (!ServletFileUpload.isMultipartContent(request)) {
			return;//終止方法運行,說明這是一個普通的表單,直接返回
		}
	    //創建上傳文件的保存路徑,建議在WEB-INF路徑下,安全,用戶無法直接訪間上傳的文件;
	    String uploadPath =this.getServletContext().getRealPath("/WEB-INF/upload");
	    File uploadFile = new File(uploadPath);
	    if (!uploadFile.exists()){
	    uploadFile.mkdir(); //創建這個月錄
	    }
		
		// 創建上傳文件的保存路徑，建議在WEB-INF路徑下，安全，用戶無法直接訪問上傳的文件
		String tmpPath = this.getServletContext().getRealPath("/WEB-INF/tmp");
		File file = new File(tmpPath);
		if (!file.exists()) {
			file.mkdir();//創建臨時目錄
		}

		// 處理上傳的文件,一般都需要通過流來獲取,我們可以使用 request, getInputstream(),原生態的文件上傳流獲取,十分麻煩
		// 但是我們都建議使用 Apache的文件上傳組件來實現, common-fileupload,它需要旅 commons-io組件;
		try {
			// 創建DiskFileItemFactory對象，處理文件路徑或者大小限制
			DiskFileItemFactory factory = getDiskFileItemFactory(file);
			/*
			 * //通過這個工廠設置一個緩沖區,當上傳的文件大於這個緩沖區的時候,將他放到臨時文件 factory.setSizeThreshold(1024 *
			 * 1024); //緩存區大小為1M factory.setRepository (file);//臨時目錄的保存目錄,需要一個File
			 */

			// 2、獲取ServletFileUpload
			ServletFileUpload upload = getServletFileUpload(factory);

			// 3、處理上傳文件
			// 把前端請求解析，封裝成FileItem對象，需要從ServletFileUpload對象中獲取
			String msg = uploadParseRequest(upload, request, uploadPath);
			
			// Servlet請求轉發消息
			System.out.println(msg);
			if(msg == "文件上傳成功!") {
				// Servlet請求轉發消息
				request.setAttribute("msg",msg);
				request.getRequestDispatcher("info.jsp").forward(request, response);
			}else {
				msg ="請上傳文件";
				request.setAttribute("msg",msg);
				request.getRequestDispatcher("info.jsp").forward(request, response);
			}

		} catch (FileUploadException e) {
			// TODO 自動生成的 catch 塊
			e.printStackTrace();
		}
	}

	public static DiskFileItemFactory getDiskFileItemFactory(File file) {
		DiskFileItemFactory factory = new DiskFileItemFactory();
		// 通過這個工廠設置一個緩沖區,當上傳的文件大於這個緩沖區的時候,將他放到臨時文件中;
		factory.setSizeThreshold(1024 * 1024);// 緩沖區大小為1M
		factory.setRepository(file);// 臨時目錄的保存目錄,需要一個file
		return factory;
	}

	public static ServletFileUpload getServletFileUpload(DiskFileItemFactory factory) {
		ServletFileUpload upload = new ServletFileUpload(factory);
		// 監聽長傳進度
		upload.setProgressListener(new ProgressListener() {

			// pBYtesRead:已讀取到的文件大小
			// pContextLength:文件大小
			public void update(long pBytesRead, long pContentLength, int pItems) {
				System.out.println("總大小：" + pContentLength + "已上傳：" + pBytesRead);
			}
		});

		// 處理亂碼問題
		upload.setHeaderEncoding("UTF-8");
		// 設置單個文件的最大值
		upload.setFileSizeMax(1024 * 1024 * 10);
		// 設置總共能夠上傳文件的大小
		// 1024 = 1kb * 1024 = 1M * 10 = 10м

		return upload;
	}

	public static String uploadParseRequest(ServletFileUpload upload, HttpServletRequest request, String uploadPath)
			throws FileUploadException, IOException {

		String msg = "";
		
		// 把前端請求解析，封裝成FileItem對象
		List<FileItem> fileItems = upload.parseRequest(request);
		for (FileItem fileItem : fileItems) {
			if (fileItem.isFormField()) {// 判斷上傳的文件是普通的表單還是帶文件的表單
				// getFieldName指的是前端表單控件的name;
				String name = fileItem.getFieldName();
				String value = fileItem.getString("UTF-8"); // 處理亂碼
				System.out.println(name + ": " + value);
			} else {// 判斷它是上傳的文件
				
				// ============處理文件==============

				// 拿到文件名
				String uploadFileName = fileItem.getName();
				System.out.println("上傳的文件名: " + uploadFileName);
				if (uploadFileName.trim().equals("") || uploadFileName == null) {
					continue;
				}

				// 獲得上傳的文件名/images/girl/paojie.png
				String fileName = uploadFileName.substring(uploadFileName.lastIndexOf("/") + 1);
				// 獲得文件的后綴名
				String fileExtName = uploadFileName.substring(uploadFileName.lastIndexOf(".") + 1);

				/*
				 * 如果文件后綴名fileExtName不是我們所需要的 就直按return.不處理,告訴用戶文件類型不對。
				 */

				System.out.println("文件信息[件名: " + fileName + " ---文件類型" + fileExtName + "]");
				// 可以使用UID（唯一識別的通用碼),保證文件名唯
				// 0UID. randomUUID(),隨機生一個唯一識別的通用碼;
				String uuidPath = UUID.randomUUID().toString();
				
				// ================處理文件完畢==============

				// 存到哪? uploadPath
				// 文件真實存在的路徑realPath
				String realPath = uploadPath + "/" + uuidPath;
				// 給每個文件創建一個對應的文件夾
				File realPathFile = new File(realPath);
				if (!realPathFile.exists()) {
					realPathFile.mkdir();
				}
				// ==============存放地址完畢==============
				
				
				// 獲得文件上傳的流
				InputStream inputStream = fileItem.getInputStream();
				// 創建一個文件輸出流
				// realPath =真實的文件夾;
				// 差了一個文件;加上翰出文件的名產"/"+uuidFileName
				FileOutputStream fos = new FileOutputStream(realPath + "/" + fileName);

				// 創建一個緩沖區
				byte[] buffer = new byte[1024 * 1024];
				// 判斷是否讀取完畢
				int len = 0;
				// 如果大於0說明還存在數據;
				while ((len = inputStream.read(buffer)) > 0) {
					fos.write(buffer, 0, len);
				}
				// 關閉流
				fos.close();
				inputStream.close();
				
				msg = "文件上傳成功!";
				fileItem.delete(); // 上傳成功,清除臨時文件
				//=============文件傳輸完成=============
			}
		}
		return msg;

	}
}

注冊xml

<servlet>
  	<servlet-name>upload</servlet-name>
  	<servlet-class>com.chen.FileSerlvet</servlet-class>
  </servlet>
  <servlet-mapping>
  	<servlet-name>upload</servlet-name>
  	<url-pattern>/upload.do</url-pattern>

導入依賴的jar包

	<!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
		<dependency>
			<groupId>commons-fileupload</groupId>
			<artifactId>commons-fileupload</artifactId>
			<version>1.4</version>
		</dependency>
	<!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
		<dependency>
			<groupId>commons-io</groupId>
			<artifactId>commons-io</artifactId>
			<version>2.6</version>
		</dependency>

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
	<body>
		<%--
		GET：上傳文件大小有限制
		POST：上傳文件大小沒有限制
		 ${pageContext.request.contextPath}
		 --%>
		<form action="upload.do" enctype="multipart/form-data"  method="post">
			上傳用戶：<input type="text" name="username"><br/>
			<P><input type="file" name="file1"></P>
			<P><input type="file" name="file1"></P>
			<P><input type="submit" value="提交"> | <input type="reset"></P>
		</form>
	</body>
</html>

info.jsp

<%@ page language="java" contentType="text/html;charset=UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<title>Insert title here</title>
</head>
<body>

<%=request.getAttribute("msg")%>

</body>
</html>