servlet-api 是servlet的核心api包
commons-fileupload 上传功能的通用工具包
fastjson 阿里的json工具包
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.1</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.7</version>
</dependency>
此项目是采用maven构建的java web项目，传统的jsp作为页面交互。
<web-app>
<listener>
<listener-class>
org.apache.commons.fileupload.servlet.FileCleanerCleanup
</listener-class>
</listener>
<servlet>
<servlet-name>FileUploadServlet</servlet-name>
<display-name>FileUploadServlet</display-name>
<description>FileUploadServlet</description>
<servlet-class>com.ghj.servlet.FileUploadServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>FileUploadServlet</servlet-name>
<url-pattern>/FileUploadServlet</url-pattern>
</servlet-mapping>
</web-app>
配置的servlet的位置，那么我们就要去写代码了。
新建一个class文件com.ghj.servlet.FileUploadServlet，继承自HttpServlet。重写它的init()和doPost()方法。
代码
package com.ghj.servlet;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.FileCleanerCleanup;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FileCleaningTracker;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
/**
* 把今天最好的表现当作明天最新的起点．．～
* いま 最高の表現 として 明日最新の始発．．～
* Today the best performance as tomorrow newest starter!
* Created by IntelliJ IDEA.
*
* @author: xiaomo
* @github: https://github.com/qq83387856
* @email: [email protected]
* @QQ_NO: 83387856
* @Date: 2016/10/24 9:15.
* @Description:
* @Copyright(©) 2016 by xiaomo.
**/
public class FileUploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private File fileUploadPath;
private static final String fileDirectory = "/data";
/**
* 设置文件存储位置
*/
@Override
public void init() {
String realPath = this.getServletConfig().getServletContext().getRealPath("/");
fileUploadPath = new File(realPath + fileDirectory);
if (!fileUploadPath.exists()) {
boolean isCreate = fileUploadPath.mkdirs();
if (isCreate) {
System.out.println("文件夹己被创建");
}
}
}
/**
* post请求(文件上传的操作)
* 说明：该方法支持同时上传多个文件（在index.jsp中添加文件上传的控件）
* 注意：文件名只能为英文
*
* @param request request
* @param response response
* @throws ServletException ServletException
* @throws IOException IOException
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
if (isMultipart) {
ServletContext servletContext = this.getServletConfig().getServletContext();
File repository = (File) servletContext.getAttribute("javax.servlet.context.tempdir");
DiskFileItemFactory factory = newDiskFileItemFactory(servletContext, repository);
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setHeaderEncoding("utf-8");
PrintWriter printWriter = response.getWriter();
response.setContentType("application/json");
response.setCharacterEncoding("utf-8");
JSONArray files = new JSONArray();
try {
List<FileItem> items = upload.parseRequest(request);
for (FileItem item : items) {
if (item.isFormField()) { //表单输入域
System.out.println(item.getFieldName());
} else { // 文件上传域
String name = item.getName();
if (!name.equals("")) {
int index = name.indexOf("\\");
File uploadedFile;
if (index == -1) {
uploadedFile = new File(fileUploadPath,
File.separator + name);
} else {
uploadedFile = new File(fileUploadPath, File.separator + name.substring(name.lastIndexOf(File.separator) + 1));
}
item.write(uploadedFile);
JSONObject file = new JSONObject();
file.put("name", name);
file.put("size", item.getSize());
file.put("url", fileUploadPath + "/" + name);
file.put("deleteType", "post");
files.add(file);
} else {
JSONObject file = new JSONObject();
file.put("result", "please choose a file");
files.add(file);
}
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
JSONObject result = new JSONObject();
result.put("files", files);
printWriter.write(result.toString());
printWriter.close();
}
}
}
/**
* 将请求的每个项目封装成单独的文件项目
*
* @param context context
* @param repository repository
* @return DiskFileItemFactory
*/
private DiskFileItemFactory newDiskFileItemFactory(ServletContext context, File repository) {
FileCleaningTracker fileCleaningTracker = FileCleanerCleanup.getFileCleaningTracker(context);
DiskFileItemFactory factory = new DiskFileItemFactory(DiskFileItemFactory.DEFAULT_SIZE_THRESHOLD, repository);
factory.setFileCleaningTracker(fileCleaningTracker);
return factory;
}
}
<html>
<%@page pageEncoding="UTF-8" contentType="text/html; charset=UTF-8" %>
<body>
<h2>文件上传</h2>
<form action="FileUploadServlet" method="post" enctype="multipart/form-data">
<input type="file" name="file1""><br>
<input type="submit" value="submit">
</form>
</body>
</html>
看起来清新简单，就不加那么style的修饰了。
https://github.com/java-user/ServletFileUploadDemo 需要的朋友自取，随意使用不用客气