一、上传单个文件
上传文件是很多Web
程序都具有的功能。在Struts1.x
中已经提供了用于上传文件的组件。而在Struts2
中提供了一个更为容易操作的上传文件组件。所不同的是,Struts1.x
的上传组件需要一个ActionForm
来传递文件,而Struts2
的上传组件是一个拦截器(这个拦截器不用配置,是自动装载的)。在本文中先介绍一下如何用struts2
上传单个文件,最后介绍一下用struts2
上传任意多个文件。
要用Struts2
实现上传单个文件的功能非常容易实现,只要使用普通的Action
即可。但为了获得一些上传文件的信息,如上传文件名、上传文件类型以及上传文件的Stream
对象,就需要按着一定规则来为Action
类增加一些getter
和setter
方法。
在Struts2
中,
用于获得和设置java.io.File
对象(Struts2
将文件上传到临时路径,并使用java.io.File
打开这个临时文件)的方法是getUpload
和setUpload
。获得和设置文件名的方法是getUploadFileName
和setUploadFileName
,获得和设置上传文件内容类型的方法是getUploadContentType
和setUploadContentType
。下面是用于上传的动作类的完整代码:
package
action;
import java.io. * ;
import com.opensymphony.xwork2.ActionSupport;
public class UploadAction extends ActionSupport
{
private File upload;
private String uploadFileName;
private String uploadContentType;
public String getUploadFileName()
{
return uploadFileName;
}
public void setUploadFileName(String fileName)
{
this .uploadFileName = fileName;
}
public File getUpload()
{
return upload;
}
public void setUpload(File upload)
{
this .upload = upload;
}
public void setUploadContentType(String contentType)
{
this .uploadContentType = contentType;
}
public String getUploadContentType()
{
return this .uploadContentType;
}
public String execute() throws Exception
{
java.io.InputStream is = new java.io.FileInputStream(upload);
java.io.OutputStream os = new java.io.FileOutputStream( " d:\\upload\\ " + uploadFileName);
byte buffer[] = new byte [ 8192 ];
int count = 0 ;
while ((count = is.read(buffer)) > 0 )
{
os.write(buffer, 0 , count);
}
os.close();
is.close();
return SUCCESS;
}
}
import java.io. * ;
import com.opensymphony.xwork2.ActionSupport;
public class UploadAction extends ActionSupport
{
private File upload;
private String uploadFileName;
private String uploadContentType;
public String getUploadFileName()
{
return uploadFileName;
}
public void setUploadFileName(String fileName)
{
this .uploadFileName = fileName;
}
public File getUpload()
{
return upload;
}
public void setUpload(File upload)
{
this .upload = upload;
}
public void setUploadContentType(String contentType)
{
this .uploadContentType = contentType;
}
public String getUploadContentType()
{
return this .uploadContentType;
}
public String execute() throws Exception
{
java.io.InputStream is = new java.io.FileInputStream(upload);
java.io.OutputStream os = new java.io.FileOutputStream( " d:\\upload\\ " + uploadFileName);
byte buffer[] = new byte [ 8192 ];
int count = 0 ;
while ((count = is.read(buffer)) > 0 )
{
os.write(buffer, 0 , count);
}
os.close();
is.close();
return SUCCESS;
}
}
在execute
方法中的实现代码就很简单了,只是从临时文件复制到指定的路径(在这里是d:\upload
)中。上传文件的临时目录的默认值是javax.servlet.context.tempdir
的值,但可以通过struts.properties
(和struts.xml
在同一个目录下)的struts.multipart.saveDir
属性设置。Struts2
上传文件的默认大小限制是2M
(2097152
字节),也可以通过struts.properties
文件中的struts.multipart.maxSize
修改,如struts.multipart.maxSize=2048
表示一次上传文件的总大小不能超过2K
字节。
下面的代码是上传文件的
JSP
页面代码
:
<%
@ page language
=
"
java
"
import
=
"
java.util.*
"
pageEncoding
=
"
GBK
"
%>
<% @ taglib prefix = " s " uri = " /struts-tags " %>
< html >
< head >
< title > 上传单个文件 </ title >
</ head >
< body >
< s:form action ="upload" namespace ="/test"
enctype ="multipart/form-data" >
< s:file name ="upload" label ="输入要上传的文件名" />
< s:submit value ="上传" />
</ s:form >
</ body >
</ html >
<% @ taglib prefix = " s " uri = " /struts-tags " %>
< html >
< head >
< title > 上传单个文件 </ title >
</ head >
< body >
< s:form action ="upload" namespace ="/test"
enctype ="multipart/form-data" >
< s:file name ="upload" label ="输入要上传的文件名" />
< s:submit value ="上传" />
</ s:form >
</ body >
</ html >
也可以在success.jsp
页中通过<s:property>
获得文件的属性
(
文件名和文件内容类型
),
代码如下
:
<s:property value="uploadFileName"/>
二、上传任意多个文件<s:property value="uploadFileName"/>
在 Struts2 中,上传任意多个文件也非常容易实现。首先,要想上传任意多个文件,需要在客户端使用 DOM 技术生成任意多个 <input type=”file” /> 标签。 name 属性值都相同。代码如下:
<
html
>
< head >
< script language ="javascript" >
function addComponent()
{
var uploadHTML = document.createElement( " <input type='file' name='upload'/> " );
document.getElementById( " files " ).appendChild(uploadHTML);
uploadHTML = document.createElement( " <p/> " );
document.getElementById( " files " ).appendChild(uploadHTML);
}
</ script >
</ head >
< body >
< input type ="button" onclick ="addComponent();" value ="添加文件" />
< br />
< form onsubmit ="return true;" action ="/struts2/test/upload.action"
method ="post" enctype ="multipart/form-data" >
< span id ="files" > < input type ='file' name ='upload' />
< p />
</ span >
< input type ="submit" value ="上传" />
</ form >
</ body >
</ html >
上面的
javascript
代码可以生成任意多个
<input type=’file’>
标签,
name
的值都为
file(要注意的是,上面的javascript代码只适合于IE浏览器,firefox等其他浏览器需要使用他的代码)
。至于
Action
类,和上传单个文件的
Action
类基本一至,只需要将三个属性的类型改为
List
即可。代码如下:
< head >
< script language ="javascript" >
function addComponent()
{
var uploadHTML = document.createElement( " <input type='file' name='upload'/> " );
document.getElementById( " files " ).appendChild(uploadHTML);
uploadHTML = document.createElement( " <p/> " );
document.getElementById( " files " ).appendChild(uploadHTML);
}
</ script >
</ head >
< body >
< input type ="button" onclick ="addComponent();" value ="添加文件" />
< br />
< form onsubmit ="return true;" action ="/struts2/test/upload.action"
method ="post" enctype ="multipart/form-data" >
< span id ="files" > < input type ='file' name ='upload' />
< p />
</ span >
< input type ="submit" value ="上传" />
</ form >
</ body >
</ html >
package
action;
import java.io. * ;
import com.opensymphony.xwork2.ActionSupport;
public class UploadMoreAction extends ActionSupport
{
private java.util.List < File > uploads;
private java.util.List < String > uploadsFileName;
private java.util.List < String > uploadsContentType;
public java.util.List < String > getUploadsFileName()
{
return uploadFileName;
}
public void setUploadFileName(java.util.List < String > fileNames)
{
this .uploadFileName = fileNames;
}
public java.util.List < File > getUploads()
{
return uploads;
}
public void setUploads(java.util.List < File > uploads)
{
this .uploads = uploads;
}
public void setUploadsContentType(java.util.List < String > contentTypes)
{
this .uploadsContentType = contentTypes;
}
public java.util.List < String > getUploadsContentType()
{
return this .uploadsContentType;
}
public String execute() throws Exception
{
if (uploads != null )
{
int i = 0 ;
for (; i < uploads.size(); i ++ )
{
java.io.InputStream is = new java.io.FileInputStream(uploads.get(i));
java.io.OutputStream os = new java.io.FileOutputStream(
" d:\\upload\\ " + uploadsFileName.get(i));
byte buffer[] = new byte [ 8192 ];
int count = 0 ;
while ((count = is.read(buffer)) > 0 )
{
os.write(buffer, 0 , count);
}
os.close();
is.close();
}
}
return SUCCESS;
}
}
import java.io. * ;
import com.opensymphony.xwork2.ActionSupport;
public class UploadMoreAction extends ActionSupport
{
private java.util.List < File > uploads;
private java.util.List < String > uploadsFileName;
private java.util.List < String > uploadsContentType;
public java.util.List < String > getUploadsFileName()
{
return uploadFileName;
}
public void setUploadFileName(java.util.List < String > fileNames)
{
this .uploadFileName = fileNames;
}
public java.util.List < File > getUploads()
{
return uploads;
}
public void setUploads(java.util.List < File > uploads)
{
this .uploads = uploads;
}
public void setUploadsContentType(java.util.List < String > contentTypes)
{
this .uploadsContentType = contentTypes;
}
public java.util.List < String > getUploadsContentType()
{
return this .uploadsContentType;
}
public String execute() throws Exception
{
if (uploads != null )
{
int i = 0 ;
for (; i < uploads.size(); i ++ )
{
java.io.InputStream is = new java.io.FileInputStream(uploads.get(i));
java.io.OutputStream os = new java.io.FileOutputStream(
" d:\\upload\\ " + uploadsFileName.get(i));
byte buffer[] = new byte [ 8192 ];
int count = 0 ;
while ((count = is.read(buffer)) > 0 )
{
os.write(buffer, 0 , count);
}
os.close();
is.close();
}
}
return SUCCESS;
}
}
在 execute 方法中,只是对 List 对象进行枚举,在循环中的代码和上传单个文件时的代码基本相同。如果读者使用过 struts1.x 的上传组件,是不是感觉 Struts2 的上传功能更容易实现呢? 在 Struts1.x 中上传多个文件时,可是需要建立带索引的属性的。而在 Struts2 中,就是这么简单就搞定了。 图 1 是上传任意多个文件的界面。
图1
在本文中给出了用Struts2上传任意多个文件的一个方法,如果哪位读者有更好的方法,请跟贴!
本文转自 androidguy 51CTO博客,原文链接:
http://blog.51cto.com/androidguy/216486
,如需转载请自行联系原作者