最简单的Struts2下载图片实例

怼烎@ 2023-10-17 10:59 2阅读 0赞

最简单的Struts2下载图片实例  
在实际项目中上传和下载是十分常见的，今天我就教大家如何利用Struts2框架来实现图片的下载

**环境的搭建**  
（申明一下 我用的是struts-2.3.31）  
一、创建一个web 工程  
![我的目录结构][SouthEast]  
二、下载好Struts2以后导入核心jar  
![十三个核心jar][jar]  
三：编写上传页面  
代码如下（index.jsp）

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    
    <html>
      <head>
        <title>下载文件</title>
      </head>
    
      <body>
         
        <a href="user/download.action">帅哥私房照</a>
      </body>
    </html>

四、编写 DownLoadAction

package com.hulang.actions;
    
    import java.io.InputStream;
    import java.util.UUID;
    
    import org.apache.struts2.ServletActionContext;
    
    public class DownLoadAction {
        
    
        private InputStream inputStream;
        private String fileName;//文件名随意
        public InputStream getInputStream() {
            return inputStream;
        }
        public void setInputStream(InputStream inputStream) {
            this.inputStream = inputStream;
        }
        public String getFileName() {
            return fileName;
        }
        public void setFileName(String fileName) {
            this.fileName = fileName;
        }
        /**
         * 
         * @return
         * @throws Exception
         * 这里强调一下：首先，在你的当前工程下先得存在/images这么个文件夹
         * 其次里面得有一张叫0.bmp的图片  不然到哪里去下载（我们的代码是要放到服务器上去的）
         */
        public String execute() throws Exception{
            fileName = "0.bmp";
            inputStream = ServletActionContext.getServletContext().getResourceAsStream("/images/"+fileName);
            //设置下载文件名  别整中文哈 我这用的是UUID生成随机名字
            fileName = UUID.randomUUID()+".bmp";
            /*
            //如果实在是需要中文怎么办呢
            fileName = "帅哥.jpg";
            //先用当前编码将其打散
            byte[] bytes = fileName.getBytes("utf-8");
            //然后用服务端的编码组装起来
            fileName = new String(bytes,"ISO-8859-1");
            */
            return "success";
        }
    }

五、注册Action（在struts.xml注册）

<?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>
        <package name="first" namespace="/user" extends="struts-default">
            <action name="download" class="com.hulang.actions.DownLoadAction">
                <result type="stream">
                    
                    <param name="contentDisposition">attachment;filename=${fileName}</param>
                    
                    <param name="inputName">inputStream</param>
                </result>
            </action>
        </package>
    </struts>

*\*搞定*，结果如下：\*  
![这里写图片描述][SouthEast 1]

![这里写图片描述][SouthEast 2]

很简单吧 简单的事情认真做！  
其实Struts2开发很简单，我小小的总结了一下开发过程（不喜勿喷）——编写页面—->编写对应的Action—>再编写对应跳转的页面 如此循环。

有问题到511906138学习群找我！谢谢

[SouthEast]: https://img-blog.csdn.net/20170225154954086?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbGVpc3VyZV9saWZl/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast
[jar]: https://img-blog.csdn.net/20170225153420408?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbGVpc3VyZV9saWZl/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast
[SouthEast 1]: https://img-blog.csdn.net/20170225155310811?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbGVpc3VyZV9saWZl/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast
[SouthEast 2]: https://img-blog.csdn.net/20170225155340343?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbGVpc3VyZV9saWZl/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast