Java框架Struts2实现图片上传

╰半橙微兮° 2022-06-11 03:23 214阅读 0赞

Struts 2 框架为处理文件上传提供了内置支持，它使用“在 HTML 中基于表单的文件上传”。当上传一个文件时，它通常会被存储在一个临时目录中，而且它们应该由 Action 类进行处理或移动到一个永久的目录，用来确保数据不丢失。服务器在恰当的位置可能有一个安全策略，它会禁止你写到除了临时目录以外的目录，而且这个目录属于你的web应用应用程序。

通过预定义的名为文件上传的拦截器，Struts 的文件上传是可能的，这个拦截器在 org.apache.struts2.interceptor.FileUploadInterceptor 类是可用的，而且是 defaultStack 的一部分。

## 创建视图文件 ##

让我们开始创建需要浏览和上传选定的文件的视图。因此，让我们创建一个带有简单的 HTML 上传表单的 index.jsp，它允许用户上传文件：（表单的编码类型设置为**multipart/form-data**）

<%--
      Created by IntelliJ IDEA.
      User: yzjxiaoyue
      Date: 2017/7/28
      Time: 19:11
      To change this template use File | Settings | File Templates.
    --%>
    <%@ page language="java" contentType="text/html; charset=utf-8"
             pageEncoding="utf-8"%>
    <%@ taglib prefix="s" uri="/struts-tags"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
        <title>File Upload</title>
    </head>
    <body>
    <form action="upload" method="post" enctype="multipart/form-data">
        <label for="myFile">Upload your file</label>
        <input type="file" name="myFile"  id="myFile"/>
        <input type="submit" value="Upload"/>
    </form>
    </body>
    </html>

之后创建success.jsp页面：

<%--
      Created by IntelliJ IDEA.
      User: yzjxiaoyue
      Date: 2017/7/28
      Time: 19:14
      To change this template use File | Settings | File Templates.
    --%>
    <%@ page contentType="text/html; charset=UTF-8" %>
    <%@ taglib prefix="s" uri="/struts-tags" %>
    <html>
    <head>
        <title>File Upload Success</title>
    </head>
    <body>
    You have successfully uploaded <s:property value="myFileFileName"/>
    </body>
    </html>

创建error.jsp页面

<%--
      Created by IntelliJ IDEA.
      User: yzjxiaoyue
      Date: 2017/7/28
      Time: 20:05
      To change this template use File | Settings | File Templates.
    --%>
    <%@ page contentType="text/html; charset=UTF-8" %>
    <%@ taglib prefix="s" uri="/struts-tags" %>
    <html>
    <head>
        <title>File Upload Error</title>
    </head>
    <body>
    There has been an error in uploading the file.
    </body>
    </html>

## 创建 action 类 ##

接下来让我们创建一个称为 **uploadFile.java** 的 Java 类，它负责上传文件，并且把这个文件存储在一个安全的位置：

package com.action;
    
    import com.opensymphony.xwork2.ActionSupport;
    import org.apache.commons.io.FileUtils;
    
    import java.io.File;
    import java.io.IOException;
    public class uploadFile extends ActionSupport{
        private File myFile;
    
        public File getMyFile() {
            return myFile;
        }
        public void setMyFile(File myFile) {
            this.myFile = myFile;
        }
    
        private String myFileContentType;
    
        private String myFileFileName;
    
        private String destPath;
    
        public String execute()
        {
             /* Copy file to a safe location */
            destPath = "E:\\Program Files\\apache-tomcat-9.0.0\\apache-tomcat-9.0.0.M22\\work\\";
            try{
                System.out.println("Src File name: " + myFile);
                System.out.println("Dst File name: " + myFileFileName);
                File destFile  = new File(destPath, myFileFileName);
                FileUtils.copyFile(myFile, destFile);
            }catch(IOException e){
                e.printStackTrace();
                return ERROR;
            }
            return SUCCESS;
        }
    
    
        public String getMyFileContentType() {
            return myFileContentType;
        }
        public void setMyFileContentType(String myFileContentType) {
            this.myFileContentType = myFileContentType;
        }
        public String getMyFileFileName() {
            return myFileFileName;
        }
        public void setMyFileFileName(String myFileFileName) {
            this.myFileFileName = myFileFileName;
        }
    }

## 配置文件 ##

<?xml version="1.0" encoding="UTF-8"?>
    
    <!DOCTYPE struts PUBLIC
            "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
            "http://struts.apache.org/dtds/struts-2.3.dtd">
    
    <struts>
        <constant name="struts.devMode" value="true"/>
        <constant name="struts.multipart.maxSize" value="10000000"/>
    
        <constant name="struts.multipart.saveDir" value="/tmp"/>
        <constant name="struts.custom.i18n.resources" value="struts"></constant>
        <package name="default" namespace="/" extends="struts-default">
            <action name="upload" class="com.action.uploadFile">
                
                <interceptor-ref name="defaultStack"/>
                <interceptor-ref name="fileUpload">
                    <param name="allowedTypes">image/jpeg,image/jpg,image/gif</param>
                </interceptor-ref>
                <result name="success">/success.jsp</result>
                <result name="error">/error.jsp</result>
            </action>
        </package>
    </struts>

界面截图

![SouthEast][]

![SouthEast 1][]

![SouthEast 2][]

[SouthEast]: /images/20220611/33dbc649b92e44609d0b988017879343.png
[SouthEast 1]: /images/20220611/a5405b0333024b549d77a83f5b7eff21.png
[SouthEast 2]: /images/20220611/3e0ce121cf2749f7aaab62e14986c5c7.png