文件上传几乎是每个web应用程序的一个必须模块，文件上传的实现需要将表单元素属性enctype的值设置成multipart/form-data，这样使表单数据以二进制编码的方式提交。下面在struts2中提供一种上传文件的方式，供大家参考。
struts2中上传文件必须添加的的jar包：commons-fileupload-x.x.x.jar和common-io-x.x.x.jar
创建一个fileUpAction来处理要上传文件的文件，代码如下：
package cn.test.fileUp;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class fileUpAction extends ActionSupport {
private static final int BUFFER_SIZE=60*60;
private File upload;//封装上传文件域的属性
private String uploadContentType;//封装上传文件的类型
private String uploadFileName;//封装上传文件名
private String savePath;//封装文件上传的保存路径
/**
*
* @param source 源文件
* @param target 目标文件
* @throws IOException
*/
private static void copy(File source,File target) throws IOException
{
InputStream inputStream=null;
OutputStream outputStream = null;
try {
inputStream=new BufferedInputStream(new FileInputStream(source));
outputStream=new BufferedOutputStream(new FileOutputStream(target),(int)source.length());
byte[] buffer=new byte[BUFFER_SIZE];
int length=0;
while((length=inputStream.read(buffer))>0)
{
outputStream.write(buffer,0,length);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if(inputStream!=null)
{
inputStream.close();
}
if(outputStream!=null)
{
outputStream.close();
}
}
public String fileUpUI()
{
return "fileUpUI";
}
@Override
public String execute() throws Exception {
// TODO Auto-generated method stub
String path1=ServletActionContext.getServletContext().getRealPath(this.getSavePath());
File f = new File(path1);
if(!f.exists())
{
f.mkdirs();
}
String path=path1+"\\"+this.getUploadFileName();
System.out.println(path1);
File target=new File(path);
copy(this.upload,target);
return "fsuccess";
}
public File getUpload() {
return upload;
}
public void setUpload(File upload) {
this.upload = upload;
}
public String getUploadContentType() {
return uploadContentType;
}
public void setUploadContentType(String uploadContentType) {
this.uploadContentType = uploadContentType;
}
public String getUploadFileName() {
return uploadFileName;
}
public void setUploadFileName(String uploadFileName) {
this.uploadFileName = uploadFileName;
}
public String getSavePath() {
return savePath;
}
public void setSavePath(String savePath) {
this.savePath = savePath;
}
public static int getBufferSize() {
return BUFFER_SIZE;
}
}
说明：在上述action中，用upload属性封装上传文件的内容，但却不能获得上传文件的类型和文件名称。因此需要使用uploadContentType来封装上传文件的类型，用uploadFileName来封装上传文件的名字，另外，配置一个savePath来封装文件保存的路径。
struts.xml文件配置如下：
<action name="file_*" class="cn.test.fileUp.fileUpAction" method="{1}">
<param name="savePath">/upload</param>
<result name="fileUpUI">/WEB-INF/jsp/fileUpUI.jsp</result>
<result name="fsuccess">/WEB-INF/jsp/fsuccess.jsp</result>
</action>
创建fileUpUI.jsp代码如下：
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<s:form action="file_execute" namespace="/" enctype="multipart/form-data">
<s:file name="upload" label="文件"></s:file>
<s:submit value="确定"></s:submit>
</s:form>
</html>
创建fsuccess.jsp代码如下：
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<html>
文件上传成功!
</html>
部署项目，在浏览器中输入：http://localhost:8080/MyWeb/file_fileUpUI，就可以实现上传文件功能。