struts2 文件下载及临时文件的删除1.文件下载配置

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我是靠谱客的博主自由老师，最近开发中收集的这篇文章主要介绍struts2 文件下载及临时文件的删除1.文件下载配置，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

1.文件下载配置

Struts2提供了stream结果类型，该结果类型是专门用于支持文件下载功能的。配置stream类型的结果需要指定以下4个属性。

　　contentType:指定被下载文件的文件类型

　　inputName:指定被下载文件的入口输入流

　　contentDisposition:指定下载的文件名

　　bufferSize:指定下载文件时的缓冲大小

struts2文件下载示例：

1) Action类

public class DownLoadFileAction {
//input
private int id;
//output
private String downLoadFileName;
public String execute(){
return "success";
}
/**
* 读取文件流
* @return
* @throws Exception
*/
public InputStream getInputStream() throws Exception{
RedisManagerModel model = new RedisManagerModel();
InputStream is = null;
try {
sample = (Sample) session.get(Sample.class, id);
//正常输出报告文件
String downLoadFilePath = sample.getFilePath();
File file = new File(downLoadFilePath);
if(!file.exists()){
this.downLoadFileName="error.txt";
ByteArrayInputStream tInputStringStream = new ByteArrayInputStream("The System Cannot Find the File Specified".getBytes());
return tInputStringStream;
}
this.downLoadFileName=sample.getFileName();
//转码
this.downLoadFileName = new String(this.downLoadFileName.getBytes(), "ISO8859-1");
is=new FileInputStream (file);
} catch (Exception e) {
e.printStackTrace();
}finally{
HibernateSessionFactory.closeSession();
}
return is ;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getDownLoadFileName() {
return downLoadFileName;
}
public void setDownLoadFileName(String downLoadFileName) {
this.downLoadFileName = downLoadFileName;
}
}

2)配置struts.xml

<!-- 文件下载 -->
<action name="downloadFile" class="xxx.xxx.action.sample.DownLoadFileAction">
<result name="success" type="stream" >
<param name="contentDisposition">attachment;fileName="${downLoadFileName}"</param>
<!--指定action中返回被下载文件的InputStream的名称-->
<param name="inputName">inputStream</param>
<!--指定下载文件的缓冲大小-->
<param name="bufferSize">1024</param>
</result>
</action>

2. 临时文件删除问题

sturts2下载是通过文件流的方式实现的,当文件正在下载的时候,因为文件流未关闭,文件句柄已被占用,所以文件无法删除.

解决问题的思路:

1).首先通过输入流/输出流将文件转成byte[]放入缓存中

2).将byte[]转成struts2要求的输入流

3).关闭文件的输入流,并删除文件

action方法改动如下:

public class DownLoadFileAction {
//input
private int id;
//output
private String downLoadFileName;
public String execute(){
return "success";
}
/**
* 读取文件流
* @return
* @throws Exception
*/
public InputStream getInputStream() throws Exception{
RedisManagerModel model = new RedisManagerModel();
InputStream is = null;
try {
sample = (Sample) session.get(Sample.class, id);
//正常输出报告文件
String downLoadFilePath = sample.getFilePath();
File file = new File(downLoadFilePath);
if(!file.exists()){
this.downLoadFileName="error.txt";
ByteArrayInputStream tInputStringStream = new ByteArrayInputStream("The System Cannot Find the File Specified".getBytes());
return tInputStringStream;
}
this.downLoadFileName=sample.getFileName();
//转码
this.downLoadFileName = new String(this.downLoadFileName.getBytes(), "ISO8859-1");
//is=new FileInputStream (file);
FileInputStream fis = new FileInputStream (file);
ByteArrayOutputStream swapStream = new ByteArrayOutputStream();
byte[] buff = new byte[1024];
int rc = 0;
while ((rc = fis.read(buff, 0, 1024)) > 0) {
swapStream.write(buff, 0, rc);
}
is=new ByteArrayInputStream(swapStream.toByteArray());
fis.close();
swapStream.close();
file.delete();//删除文件
} catch (Exception e) {
e.printStackTrace();
}finally{
HibernateSessionFactory.closeSession();
}
return is ;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getDownLoadFileName() {
return downLoadFileName;
}
public void setDownLoadFileName(String downLoadFileName) {
this.downLoadFileName = downLoadFileName;
}
}