struts2实现文件上传下载

布满荆棘的人生 2022-06-07 13:05 207阅读 0赞

**文件上传视图 ：**

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>首页</title>
    </head>
    <body>
    	<form action="upload.action" method="post" enctype="multipart/form-data">
    		文件：<input type="file" name="logo"/>
    		<input type="submit" value="提交">
    	</form>
    	
    	文件下载: ${logoFileName }</a><br>
        <a>文件大小：${fileSize }</a><br>
        <a>文件上传时间：${uploadDate }</a><br>
        
        <a href="download?logoFileName=${downFileName } ">查看</a>
    	
    </body>
    </html>

首先，表单的enctype设置为multipart/form-data，要使得文件上传拦截器成功处理文件上传，这个就必须设置。然后要注意的是表单的action方法上传和文件上传字段的名称（即logoFileName ）。我们需要这些信息来创建action方法和struts配置。

**文件下载视图：**

<%@ 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>文件下载</title>
        
    
      </head>
      
      <body>
        文件下载:<a href="download?logoFileName=${downFileName }">${logoFileName }</a><br>
        <a>文件大小：${fileSize }KB</a><br>
        <a>文件上传时间：${uploadDate }</a>
      </body>
    </html>

**创建Action类：**

import java.io.File;
    
    
    
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    
    
    import java.io.InputStream;
    import java.sql.Timestamp;
    import java.text.SimpleDateFormat;
    import java.util.Date;
    
    import org.apache.commons.io.FileUtils;
    import org.apache.struts2.ServletActionContext;
    
    import com.opensymphony.xwork2.ActionSupport;
    
    //上传和下载文件
    
    public class UploadAction extends ActionSupport{
    	private File logo;
    	private String logoFileName;
    	private String logoContentType;
    	private String fileSize;
    	private String uploadDate;
    	
    	public void setFileSize(String fileSize) {
    		this.fileSize = fileSize;
    	}
    	
    	public String getFileSize() {
    		return fileSize;
    	}
    	
    	public void setUploadDate(String uploadDate) {
    		this.uploadDate = uploadDate;
    	}
    	
    	public String getUploadDate() {
    		return uploadDate;
    	}
    	
    	private static String downFileName;
    	
    	public  String getDownFileName() {
    		return downFileName;
    	}
    
    	public  void setDownFileName(String downFileName) {
    		this.downFileName = downFileName;
    	}
    
    	//上传文件
    	public String uploadFile(){
    		 //String path=ServletActionContext.getRequest().getRealPath("/upload");
    		 String path="E:/upload";
    		 
    		 SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式
    		 uploadDate = df.format(new Date());
    		 System.out.println(uploadDate);// new Date()为获取当前系统时间
    	
    		 fileSize = (logo.length()/1024+1)+"KB";
    		 System.out.println("文件大小："+fileSize);
    		 System.out.println(logoFileName);
    		 downFileName=logoFileName;
    		 System.out.println(downFileName);
    		 try {
    			FileUtils.copyFile(logo, new File(path,logoFileName));
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    		return "success";
    	}
    	
    	//ָ指定下载路径
    	public InputStream getInputStream() throws FileNotFoundException{
    		String path="E:/upload";
    		System.out.println(path+"/"+downFileName);
    		return new FileInputStream(path+"/"+downFileName);
    	}
    	
    	public String downloadFile(){
    		return "success";
    	}
    	
    	public File getLogo() {
    		return logo;
    	}
    	public void setLogo(File logo) {
    		this.logo = logo;
    	}
    	public String getLogoFileName() {
    		return logoFileName;
    	}
    	public void setLogoFileName(String logoFileName) {
    		this.logoFileName = logoFileName;
    	}
    	public String getLogoContentType() {
    		return logoContentType;
    	}
    	public void setLogoContentType(String logoContentType) {
    		this.logoContentType = logoContentType;
    	}
    
    }

默认情况下，FileUpload拦截器为你提供三个参数，它们分别按以下方式命名：

1. [文件名参数] - 这是用户已上传的实际文件。在这个例子中它将是“logoFile”
     2. [文件名参数]ContentType - 这是上传的文件的内容类型。在这个例子中，它将是“logoContentType”
     3. [文件名参数]FileName - 这是上传的文件的名称。在这个例子中，它将是“logoFileName”

**struts配置：**

<action name="upload" class="uploadAction" method="uploadFile">
    			<result  name="success" >/hello.jsp</result>
    		</action>
    		
    		
    		<action name="download" class="uploadAction" method="downloadFile">
    			<result type="stream">
    				 <param name="inputName">inputStream</param>
    				<param name="contentDisposition">
    					attachment;filename=${uploadFileName}
    				</param>
    			</result>
    		</action>

**修改上传文件的大小：**