SpringMVC 通過commons-fileupload實現檔案上傳

jiawei3998發表於2021-01-31
SpringMVC

目錄

配置

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="https://jakarta.ee/xml/ns/jakartaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_5_0.xsd"
         version="5.0">
    <!--註冊DispatcherServlet-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

SpringMVC配置檔案 applicationContext.xml

上傳檔案的核心配置類：CommonsMultipartResolver，注意id="multipartResolver"不要寫錯

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       https://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--配置自動掃描controller包-->
    <context:component-scan base-package="com.pro.controller"/>
    <!--配置靜態資源過濾-->
    <mvc:default-servlet-handler/>
    <!--配置註解驅動-->
    <mvc:annotation-driven/>

    <!--配置檢視解析器-->
    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!--字首-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <!--字尾-->
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--SpringMVC檔案上傳配置-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!--設定請求的編碼格式, 必須和pageEncoding的屬性一致, 以便正確讀取表單的值, 預設為ISO-8859-1-->
        <property name="defaultEncoding" value="utf-8"/>
        <!--上傳檔案的大小限制, 單位為位元組 (10485760 = 10M)-->
        <property name="maxUploadSize" value="10485760"/>
        <property name="maxInMemorySize" value="40960"/>
    </bean>
</beans>


檔案上傳 Controller

上傳實現一

package com.pro.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.commons.CommonsMultipartFile;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Map;

@RestController
public class FileController {
    /*
     * 採用file.transferTo 來儲存上傳的檔案
     */
    @RequestMapping("/upload2")
    public Map fileUpload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {

        //上傳路徑儲存設定
        String path = request.getServletContext().getRealPath("/upload");
        File realPath = new File(path);
        if (!realPath.exists()){
            realPath.mkdir();
        }
        //上傳檔案地址
        System.out.println("上傳檔案儲存地址 --> "+realPath);

        //通過CommonsMultipartFile的方法直接寫檔案（注意這個時候）
        file.transferTo(new File(realPath +"/"+ file.getOriginalFilename()));

        Map<Object, Object> hashMap = new HashMap<>();
        hashMap.put("code", 0);
        hashMap.put("msg", "上傳成功");

        return hashMap;
    }
}

上傳實現二

這裡的檔名稱沒有使用 UUID組合名稱 為了方便測試

package com.pro.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.commons.CommonsMultipartFile;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Map;

@RestController
public class FileController {

    // @RequestParam("file") 將 name=file 控制元件得到的檔案封裝成 CommonsMultipartFile 物件
    // 批量上傳把 CommonsMultipartFile 改為陣列即可
    @RequestMapping("/upload")
    public String upload(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
        // 獲取檔名稱
        String uploadFileName = file.getOriginalFilename();

        // 如果檔名為空, 直接返回首頁
        if ("".equals(uploadFileName)) {
            return "file upload error";
        }

        System.out.println("上傳檔名 --> " + uploadFileName);


        // 設定檔案的儲存位置
        String path = request.getServletContext().getRealPath("/upload");
        // 判斷路徑是否存在
        File realPath = new File(path);
        if (!realPath.exists()) {
            // 如果不存在就建立
            realPath.mkdir();
        }

        System.out.println("檔案儲存路徑 --> " + realPath);

        // 獲取檔案輸入流
        InputStream is = file.getInputStream();
        // 獲取檔案輸出流
        FileOutputStream os = new FileOutputStream(new File(realPath, uploadFileName));

        // 緩衝區讀寫檔案
        byte[] buffer = new byte[1024];
        int len;
        while ((len = is.read(buffer)) != -1) {
            os.write(buffer, 0, len);
            os.flush();
        }

        // 關閉流
        os.close();
        is.close();

        return "file upload success";
    }
}

測試

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
    <form enctype="multipart/form-data" action="${pageContext.request.contextPath}/upload2" method="post">
      <input type="file" name="file">
      <input type="submit" value="上傳實現一">
    </form>
    
    
    <form enctype="multipart/form-data" action="${pageContext.request.contextPath}/upload" method="post">
      <input type="file" name="file">
      <input type="submit" value="上傳實現二">
    </form>
  </body>
</html>

依賴

核心依賴就是 commons-fileupload

<!--匯入依賴-->
<dependencies>
    <!--單元測試-->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13</version>
    </dependency>
    <!--spring-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.2.0.RELEASE</version>
    </dependency>
    <!--檔案上傳-->
    <dependency>
        <groupId>commons-fileupload</groupId>
        <artifactId>commons-fileupload</artifactId>
        <version>1.3.3</version>
    </dependency>
    <!--servlet-api匯入高版本的-->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
    </dependency>
    <!--jsp-->
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.2</version>
    </dependency>
    <!--jstl表示式-->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>
</dependencies>

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