文件下載是一個很常見的功能,用struts2實現文件下載的步驟:
一)定義一個Action類,FileDownload.Java
- package com.struts2.filedownload;
- import java.io.InputStream;
- import org.apache.struts2.ServletActionContext;
- import com.opensymphony.xwork2.ActionSupport;
- //文件下載
- public class FileDownload extends ActionSupport{
- private int number ;
- private String fileName;
- public int getNumber() {
- return number;
- }
- public void setNumber(int number) {
- this.number = number;
- }
- public String getFileName() {
- return fileName;
- }
- public void setFileName(String fileName) {
- this.fileName = fileName;
- }
- //返回一個輸入流,作爲一個客戶端來說是一個輸入流,但對於服務器端是一個 輸出流
- public InputStream getDownloadFile() throws Exception
- {
- if(1 == number)
- {
- this.fileName = “Dream.jpg” ;
- //獲取資源路徑
- return ServletActionContext.getServletContext().getResourceAsStream(“upload/Dream.jpg”) ;
- }
- else if(2 == number)
- {
- this.fileName = “jd2chm源碼生成chm格式文檔.rar” ;
- //解解亂碼
- this.fileName = new String(this.fileName.getBytes(“GBK”),“ISO-8859-1”);
- return ServletActionContext.getServletContext().getResourceAsStream(“upload/jd2chm源碼生成chm格式文檔.rar”) ;
- }
- else
- return null ;
- }
- @Override
- public String execute() throws Exception {
- return SUCCESS;
- }
- }
package com.struts2.filedownload;
import java.io.InputStream;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
//文件下載
public class FileDownload extends ActionSupport{
private int number ;
private String fileName;
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}
public String getFileName() {
return fileName;
}
public void setFileName(String fileName) {
this.fileName = fileName;
}
//返回一個輸入流,作爲一個客戶端來說是一個輸入流,但對於服務器端是一個 輸出流
public InputStream getDownloadFile() throws Exception
{
if(1 == number)
{
this.fileName = "Dream.jpg" ;
//獲取資源路徑
return ServletActionContext.getServletContext().getResourceAsStream("upload/Dream.jpg") ;
}
else if(2 == number)
{
this.fileName = "jd2chm源碼生成chm格式文檔.rar" ;
//解解亂碼
this.fileName = new String(this.fileName.getBytes("GBK"),"ISO-8859-1");
return ServletActionContext.getServletContext().getResourceAsStream("upload/jd2chm源碼生成chm格式文檔.rar") ;
}
else
return null ;
}
@Override
public String execute() throws Exception {
return SUCCESS;
}
}
二)在struts.xml文件中配置相關信息
- <struts>
- <package name=“struts2” extends=“struts-default”>
- <action name=“FileDownload” class=“com.struts2.filedownload.FileDownload”>
- <result name=“success” type=“stream”>
- <param name=“contentType”>text/plain</param>
- <param name=“contentDisposition”>attachment;fileName=“${fileName}”</param>
- <param name=“inputName”>downloadFile</param>
- <param name=“bufferSize”>1024</param>
- </result>
- </action>
- </package>
- </struts>
<struts>
<package name=”struts2” extends=”struts-default”>
<action name=”FileDownload” class=”com.struts2.filedownload.FileDownload”>
<result name=”success” type=”stream”>
<param name=”contentType”>text/plain</param>
<param name=”contentDisposition”>attachment;fileName=”${fileName}”</param>
<param name=”inputName”>downloadFile</param>
<param name=”bufferSize”>1024</param>
</result>
</action>
</package>
</struts>
1.結果類型必須要寫成 type=”stream” ,與之對應的處理類是 org.apache.struts2.dispatcher.StreamResult
2.涉及到的參數:
3.
1) <param name=”contentDisposition”>attachment;fileName=”${fileName}”</param>
contentDisposition默認是 inline(內聯的), 比如說下載的文件是文本類型的,就直接在網頁上打開,不能直接打開的纔會打開下載框自己選擇
2) attachment :下載時會打開下載框
3) fileName=”${fileName}” :在這定義的名字是一個動態的,該名字是顯示在下載框上的文件名字
4.<param name=”inputName”>downloadFile</param>,這個downloadFile名字要和FileDownload.java類中的getDownloadFile()方法名去掉get 一致
三)用於顯示下載的鏈接界面 filedownload.jsp
- <%@ 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 ‘filedownload.jsp’ starting page</title>
- <meta http-equiv=“pragma” content=“no-cache”>
- <meta http-equiv=“cache-control” content=“no-cache”>
- <meta http-equiv=“expires” content=“0”>
- <meta http-equiv=“keywords” content=“keyword1,keyword2,keyword3”>
- <meta http-equiv=“description” content=“This is my page”>
- <!–
- <link rel=”stylesheet” type=”text/css” href=”styles.css”>
- –>
- </head>
- <body>
- <h2>文件下載內容:</h2><br/>
- Dream.jpg:<a href=“FileDownload.action?number=1”>點擊下載</a><br/>
- jd2chm源碼生成chm格式文檔.rar:<a href=“FileDownload.action?number=2”>點擊下載2</a>
- </body>
- </html>
<%@ 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 'filedownload.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<h2>文件下載內容:</h2><br/>
Dream.jpg:<a href="FileDownload.action?number=1">點擊下載</a><br/>
jd2chm源碼生成chm格式文檔.rar:<a href="FileDownload.action?number=2">點擊下載2</a>
</body>
</html>