文件上传(多文件上传)/下载

Posted 2020-08-14 晨曦-荒微凉

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通常我们会涉及到上传文件和下载文件，在没接struts2框架之前，我们都是使用apache下面的commons子项目的FileUpload组件来进行文件的上传，但是那样做的话，代码看起来比较繁琐，而且不灵活，在学习了struts2后，struts2为文件上传下载提供了更好的实现机制，在这里我分别就文件下载和多文件上传的源代码进行一下讲

文件上传

首先先创建jsp页面(用于多文件上传)

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://"
            + request.getServerName() + ":" + request.getServerPort()
            + path + "/";
%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>登录页面</title>

</head>

<body>

    <s:form action="upload.action" enctype="multipart/form-data" method="post">
        
        <s:file name="upload" label="选择文件" />
        <br />
        <s:file name="upload" label="选择文件" />
        <br />
        <s:file name="upload" label="选择文件" />
        <br />
        <s:submit name="submit" value="上传文件"></s:submit>
    </s:form>

</body>
</html>

success.jsp页面(用来显示上传成功后的文件和文件类型)

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://"
            + request.getServerName() + ":" + request.getServerPort()
            + path + "/";
%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>成功页面</title>

</head>

<body>
    您所上传的文件是:<s:property value="uploadFileName"/><br/>
    文件类型:<s:property value="uploadCOntentType"/>


</body>
</html>

接下来创建UploadAction类

package cn.happy.action;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class UploadAction extends ActionSupport {


    // 上传文件的属性
    private File[] upload;
    // 上传文件的类型
    private String[] uploadContentType;
    // 上传文件的名称
    private String[] uploadFileName;
    // 上传文件的地址
    private String savePath;
    
    @Override
    public String execute() throws Exception {
        byte[] buffer=new byte[1024];
        for (int i = 0; i < upload.length; i++) {
            
            //建立上传文件的输入流
            FileInputStream fis=new FileInputStream(getUpload()[i]);
            //建立上传文件的输出流, getImageFileName()[i]
            FileOutputStream fos=new FileOutputStream(getSavePath()+"\\\\"+getUploadFileName()[i]);
            int length=fis.read(buffer);
            while(length>0){
                fos.write(buffer,0,length);
                length = fis.read(buffer);
                
            }
            fis.close();
            fos.flush();
            fos.close();
        }
        return SUCCESS;
    }
    
    
    
    public String getSavePath() {
        return ServletActionContext.getServletContext().getRealPath(savePath);
    }
    public void setSavePath(String savePath) {
        this.savePath = savePath;
    }
    
    public File[] getUpload() {
        return upload;
    }
    public void setUpload(File[] upload) {
        this.upload = upload;
    }
    public String[] getUploadContentType() {
        return uploadContentType;
    }
    public void setUploadContentType(String[] uploadContentType) {
        this.uploadContentType = uploadContentType;
    }
    public String[] getUploadFileName() {
        return uploadFileName;
    }
    public void setUploadFileName(String[] uploadFileName) {
        this.uploadFileName = uploadFileName;
    }
    
    
    
    
    

}

最后编写配置文件struts.xml

<?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>
    <!-- 动态方法调用 -->
 
    <constant name="struts.devMode" value="false" />
    
    
    <package name="default" namespace="/" extends="struts-default">
        
        <action name="upload" class="cn.happy.action.UploadAction" method="execute">
            <param name="savePath">/image</param>
           <result name="success">/upload/success.jsp</result>
        </action>
    </package>
</struts>

实现效果展示

选择文件后

文件下载

编写jsp页面

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP \'index.jsp\' starting page</title>
  </head>
  
  <body>
   <a href="download.action?fileName=1.jpg">点击此处下载文档</a>
  </body>
</html>

创建FileDownAction类

package action;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class FileDownAction extends ActionSupport {
    //读取下载文件的目录
    private String inputPath;
    //下载的文件名
    private String FileName;
    //读取下载文件的输入流
    private InputStream inputStream;
    //下载文件的类型
    private String conetntType;
    
    //创建InputStream输入流
    public InputStream getInputStream() throws IOException {
        System.out.println("123");
        String path=ServletActionContext.getServletContext().getRealPath(inputPath);
        return new BufferedInputStream(new FileInputStream(path+"\\\\"+FileName));
    }
    
    @Override
    public String execute() throws Exception{
        return SUCCESS;
    }
    
    
    public String getInputPath() {
        return inputPath;
    }
    public String getFileName() {
        return FileName;
    }
    public String getConetntType() {
        return conetntType;
    }
    public void setInputPath(String inputPath) {
        this.inputPath = inputPath;
    }
    public void setFileName(String fileName) {
        FileName = fileName;
    }
    public void setInputStream(InputStream inputStream) {
        this.inputStream = inputStream;
    }
    public void setConetntType(String conetntType) {
        this.conetntType = conetntType;
    }
}

编写配置文件struts.xml

<?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>
         <package name="default" namespace="/" extends="struts-default"> 
            <action name="download" class="action.FileDownAction">
                <param name="inputPath">/image</param>
                <result name="success" type="stream">
                <param name="contentType">application/octet-stream</param>
                <param name="inputName">inputStream</param>
                <param name="contentDisposition">attachment;Filename="${FileName}"</param>
                <param name="bufferSize">4096</param>
                </result>
            </action>
         </package> 
    
    
</struts>

最后在webRoot目录下创建image文件里面保存下载用到的文件

实现效果

点击文件下载

附加

导入jar包

web.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
    xmlns="http://java.sun.com/xml/ns/javaee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <display-name></display-name>    
  
   <filter>
    <filter-name>struts2</filter-name>
    <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
  </filter>
  <filter-mapping>
   <filter-name>struts2</filter-name>
   <url-pattern>/*</url-pattern>  
  </filter-mapping>
  
  
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

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