Servlet 文件上传

最新推荐文章于 2025-09-13 09:06:35 发布

weixin_30836759

最新推荐文章于 2025-09-13 09:06:35 发布

阅读量50

点赞数

CC 4.0 BY-SA版权

文章标签： java web.xml

原文链接：http://www.cnblogs.com/seliote/p/9728048.html

pom.xml 中先添加依赖

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>3.1.0</version>
    <scope>provided</scope>
</dependency>

上传用的 JSP

<%@ page contentType="text/html" pageEncoding="UTF-8" language="java" %>
<html>
<head>
    <title>File Upload</title>
</head>
<body>
    <h2>Select a file:</h2><br /><br />
    <form method="post" action="/upload" enctype="multipart/form-data">
        <input type="file" name="userFile" /><br />
        <input type="submit" value="Submit" />
    </form>
</body>
</html>

创建 Servlet 类

package com.seliote;

import javax.servlet.ServletException;
import javax.servlet.http.Part;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

public class FileUploadServlet extends javax.servlet.http.HttpServlet {
    protected void doPost(javax.servlet.http.HttpServletRequest request,
                          javax.servlet.http.HttpServletResponse response)
            throws ServletException, IOException {
        // Get Part
        Part part = request.getPart("userFile");
        if (part == null) {
            // Log it
            return;
        }

        // Read file
        InputStream inputStream = part.getInputStream();
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int readLength = -1;
        while ((readLength = inputStream.read(buffer)) != -1) {
            byteArrayOutputStream.write(buffer, 0, readLength);
        }
        response.getWriter().println("file length: " + byteArrayOutputStream.size());
        byteArrayOutputStream.close();
    }

    protected void doGet(javax.servlet.http.HttpServletRequest request,
                         javax.servlet.http.HttpServletResponse response)
            throws ServletException, IOException {
        request.getRequestDispatcher("/index.jsp").forward(request, response);
    }
}

修改部署描述符 web.xml

<servlet>
    <servlet-name>FileUploadServlet</servlet-name>
    <servlet-class>com.seliote.FileUploadServlet</servlet-class>
    <!-- 通知 Web 容器该 Servlet 支持接收文件上传 -->
    <multipart-config>
        <!-- 临时文件存储位置，忽略该标签则使用默认位置 -->
        <location>/tmp</location>
        <!-- 单个文件上传大小限制 -->
        <max-file-size>20971520</max-file-size>
        <!-- 请求大小限制（比如同时上传了多个文件） -->
        <max-request-size>41943040</max-request-size>
        <!-- 阀值，小于这个大小的文件将直接在内存中处理而不是写入临时文件夹 -->
        <file-size-threshold>5242880</file-size-threshold>
    </multipart-config>
</servlet>
<servlet-mapping>
    <servlet-name>FileUploadServlet</servlet-name>
    <url-pattern>/upload</url-pattern>
</servlet-mapping>

转载于:https://www.cnblogs.com/seliote/p/9728048.html