國慶七篇-----struts2的檔案上傳下載（一）
阿新 • • 發佈：2018-12-12
struts2提供了檔案的上傳下載功能，不過需要我們對其提供相關的檔案引數。
比如檔案上傳，必須提供三種屬性，並對其提供setter和getter方法，而且必須按照以下規範命名：
private File XXX;
private String XXXFileName;
private String XXXContentType;
注意：必須是上面的格式，即XXX，XXX+FileName，XXX+ContentType。如果不是上面的形式，攔截器不會對其賦值。
下面是程式碼：（MyFileUpload.java)
package com.hncj.edu; import java.io.File; import java.io.IOException; import org.apache.commons.io.FileUtils; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.ActionSupport; public class MyFileUpload extends ActionSupport{ private File upload; private String uploadFileName; private String uploadContentType; //三種屬性格式固定 public File getUpload() { return upload; } public void setUpload(File upload) { this.upload = upload; } public String getUploadFileName() { return uploadFileName; } public void setUploadFileName(String uploadFileName) { this.uploadFileName = uploadFileName; } public String getUploadContentType() { return uploadContentType; } public void setUploadContentType(String uploadContentType) { this.uploadContentType = uploadContentType; } public String executeUpload() { String realPath = ServletActionContext.getServletContext().getRealPath("/WEB-INF/upload"); File uploadDir = new File(realPath); if(!uploadDir.exists()) { uploadDir.mkdir(); } try { //複製檔案呼叫copyFile就行了 FileUtils.copyFile(upload, new File(realPath+File.separator+uploadFileName)); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return "success"; } }
上傳檢視：（upload.jsp)
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib uri="/struts-tags" prefix="s"%> <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert title here</title> </head> <body> <s:actionerror/> <s:form action="upload" method="post" enctype="multipart/form-data"> <s:file name="upload" label="請選擇檔案"></s:file> <s:submit label="提交"/> </s:form> </body> </html>
上傳成功後跳轉到下載檢視，顯示所有可以下載的檔案：（result.jsp)
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib uri="/struts-tags" prefix="s"%> <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert title here</title> </head> <body> //頁面中發出list.action請求，在showFileItems.jsp頁面中顯示所有檔案項，並將showFileItems.jsp的內容顯示在result.jsp頁面中 <s:action name="list" executeResult="true"/> </body> </html>
showFileItems.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<table>
<s:iterator var="item" value="fileNames">
<tr>
<td>${item}</td>
<td>
//這裡要用url標籤，不然傳遞中文檔名會報錯
<s:url var="url" value="download">
<s:param name="fileName">${item}</s:param>
</s:url>
//使用上面url標籤定義的值
<s:a href="%{#url}">下載</s:a>
</td>
</tr>
</s:iterator>
</table>
<s:debug></s:debug>
</body>
</html>顯示檔案項的Action：（ListAllFiles.java)
package com.hncj.edu;
import java.io.File;
import org.apache.struts2.ServletActionContext;
public class ListAllFiles {
private String[] fileNames;
public String[] getFileNames() {
return fileNames;
}
public void setFileNames(String[] fileNames) {
this.fileNames = fileNames;
}
public String listFiles() {
String realPath = ServletActionContext.getServletContext().getRealPath("/WEB-INF/upload");
File dir = new File(realPath);
//獲取上傳目錄下所有檔案的檔名
fileNames = dir.list();
return "success";
}
}
下載的action：(MyFileDownload.java)
檔案下載必須要提供對應檔案的輸入流，為其賦值，並提供get方法。
package com.hncj.edu;
import java.io.InputStream;
import org.apache.struts2.ServletActionContext;
public class MyFileDownload {
private InputStream input; //必須的
private String fileName; //還可以提供ContentType，ContentLength等屬性
public InputStream getInput() {
return input;
}
public void setInput(InputStream input) {
this.input = input;
}
public String getFileName() {
return fileName;
}
public void setFileName(String fileName) {
this.fileName = fileName;
}
public String execute() {
this.input = ServletActionContext.getServletContext().getResourceAsStream("/WEB-INF/upload"+"/"+fileName);
return "success";
}
}
strust.xml配置檔案
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
"http://struts.apache.org/dtds/struts-2.5.dtd">
<struts>
<constant name="struts.devMode" value="true"/>
<package name="pack1" extends="struts-default">
<action name="upload" class="com.hncj.edu.MyFileUpload" method="executeUpload">
<interceptor-ref name="defaultStack">
<!--限制檔案上傳的大小-->
<param name="fileUpload.maximumSize">102400</param>
<!--限制檔案的字尾名-->
<param name="fileUpload.allowedExtensions">.txt</param>
<!--還可以限制檔案的型別-->
<param name="fileUpload.allowedTypes>image/jpeg<param>
</interceptor-ref>
<result name="success">result.jsp</result>
<result name="input">upload.jsp</result>
</action>
<action name="list" class="com.hncj.edu.ListAllFiles" method="listFiles">
<result>showFileItems.jsp</result>
</action>
<action name="download" class="com.hncj.edu.MyFileDownload">
<result type="stream">
<!--inputName要和action中的輸入流名字相同-->
<param name="inputName">input</param>
<!--設定下載方式開啟-->
<param name="contentDisposition">attachment;filename=${fileName}</param>
<!--設定緩衝區大小-->
<param name="bufferSize">4096</param>
</result>
</action>
</package>
</struts>執行結果：
