原生Servlet 上传文件 -云博客

原生Servlet 上传文件

# 前端 2024-05-05 01:51 0 39 来源：云博客

依赖jar

 <dependency> <groupId>commons-fileupload</groupId> <artifactId>commons-fileupload</artifactId> <version>1.4</version> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>4.0.1</version> <scope>provided</scope> </dependency>

示例如下：

1. 新建Maven项目 upload

　　war 类型

2. pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.java</groupId> <artifactId>upload</artifactId> <version>1.0.0</version> <packaging>war</packaging> <dependencies> <dependency> <groupId>commons-fileupload</groupId> <artifactId>commons-fileupload</artifactId> <version>1.4</version> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>4.0.1</version> <scope>provided</scope> </dependency> </dependencies> <build> <finalName>${project.artifactId}</finalName> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>1.8</source> <target>1.8</target> <encoding>UTF-8</encoding> </configuration> </plugin> </plugins> </build></project>

3. UploadFileServlet.java

package com.java.servlet;import java.io.File;import java.io.IOException;import java.io.PrintWriter;import java.util.HashMap;import java.util.List;import java.util.Map;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.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;public class UploadFileServlet extends HttpServlet { private static final long serialVersionUID = -755404037178760784L; /** * 设置字符集为UTF-8 */ private static final String ENCODING = "UTF-8"; @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { if (ServletFileUpload.isMultipartContent(request)) { try { DiskFileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); List<FileItem> items = upload.parseRequest(request); // 存储普通表单参数 Map<String, String> paramMap = new HashMap<>(); // 存储文件参数 Map<String, FileItem> fileMap = new HashMap<>(); /* 解析表单参数 */ for (FileItem item : items) { // 普通表单参数 if (item.isFormField()) { paramMap.put(item.getFieldName(), item.getString(ENCODING)); } // 文件参数 else { fileMap.put(item.getFieldName(), item); } } /* 从参数集合中获取需要的参数 */ String uploadPath = paramMap.get("uploadPath"); FileItem fileItem = fileMap.get("file"); String fileName = fileItem.getName(); File outFile = new File(uploadPath, fileName); fileItem.write(outFile); write(response, "上传完成:" + outFile.getAbsolutePath()); } catch (FileUploadException e) { e.printStackTrace(); write(response, e.getMessage()); } catch (Exception e) { e.printStackTrace(); write(response, e.getMessage()); } } } private void write(HttpServletResponse response, String message) { response.setContentType("text/html; charset=UTF-8"); PrintWriter writer = null; try { writer = response.getWriter(); writer.write(message); writer.flush(); } catch (IOException e) { e.printStackTrace(); } finally { writer.close(); } }}

4. web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5"> <display-name>upload</display-name> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>uploadFile</servlet-name> <servlet-class>com.java.servlet.UploadFileServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>uploadFile</servlet-name> <url-pattern>/uploadFile</url-pattern> </servlet-mapping></web-app>

5. 新建页面文件 src/main/webapp/index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><% String path = request.getContextPath(); String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";%><!DOCTYPE html><html> <head> <title>上传文件</title> <base href="<%=basePath%>"> <meta http-equiv="content-type" content="text/html; charset=UTF-8" /> </head> <body> <form action="uploadFile" enctype="multipart/form-data" method="post"> <table> <tr> <th>选择上传文件:</th> <td><input name="file" type="file" /></td> </tr> <tr> <th>上传服务器路径:</th> <td><input name="uploadPath" type="text" placeholder="上传服务器路径" /></td> </tr> <tr> <td colspan="2"><button type="submit">上传</button></td> </tr> </table> </form> </body></html>