（1）原理：Struts 2框架没有提供文件上传的解析器（也可以说没有提供自己的文件上传组件），它是借助于其他文件上传组件。例如，Struts 2默认的使用Jakarta的commons-fileupload.jar和commons-io.jar。但Struts 2在原有的上传解析器中做了更进一步的封装，更进一步简化上传文件。
（2）首先，在struts.properties文件中配置Struts 2上传文件的解析器
#默认的使用Jakarta的commons-fileupload文件解析器
struts.multipart.parser = jakarta
（3）在WEB-INF/lib中加入两个包，commons-fileupload.jar和commons-io.jar。
（4）编写实现文件上传的Action类，代码如下：
package com.gxa.edu.struts2.ch4.action;
/**
* 利用Struts 2实现文件上传功能
* @author Administrator
*
*/
import
java
.io.File;
import java.io.FileOutputStream;
import java.io.FileInputStream;
import org.apache.struts2.ServletActionContext;
public class FileUploadAction {
private File fileUpload;//获取上传文件
private String fileUploadContentType;//获取上传文件的类型，注意上传类型变量命名方式
private String fileUploadFileName;//获取上传文件的名称
private String fileSavePath;//设置上传文件的保存路径，利用struts2框架的设置注入。在struts.xml文件配置<param name = "fileSavePath"/>关键字
public String getFileSavePath() {
return ServletActionContext.getServletContext().getRealPath(fileSavePath);
}
public void setFileSavePath(String fileSavePath) {
this.fileSavePath = fileSavePath;
}
public File getFileUpload() {
return fileUpload;
}
public void setFileUpload(File fileUpload) {
this.fileUpload = fileUpload;
}
public String getFileUploadContentType() {
return fileUploadContentType;
}
public void setFileUploadContentType(String fileUploadContentType) {
this.fileUploadContentType = fileUploadContentType;
}
public String getFileUploadFileName() {
return fileUploadFileName;
}
public void setFileUploadFileName(String fileUploadFileName) {
this.fileUploadFileName = fileUploadFileName;
}
public String upload() throws Exception {
System.out.println("===利用struts2上传文件===");
System.out.println("文件类型===" + this.fileUploadContentType);
FileInputStream fis = new FileInputStream(getFileUpload());
File file = new File(getFileSavePath().replaceAll("\\\\", "/"));
if (!file.exists()) {
file.mkdirs();
}
FileOutputStream fos = new FileOutputStream(getFileSavePath().replaceAll("\\\\", "/") + "/" + getFileUploadFileName());
int i = 0;
byte[] buf = new byte[1024];
while ((i = fis.read(buf)) != -1) {
fos.write(buf, 0, i);
}
return "success";
}
}
（5）编写一个upload.jsp文件，代码如下：
<%@ page language="java" pageEncoding="GBK"%> <%@ taglib prefix = "s" uri = "/struts-tags" %> <% 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 upload.jsp starting page</title> <meta. http-equiv="pragma" c> <meta. http-equiv="cache-control" c> <meta. http-equiv="expires" c> <meta. http-equiv="keywords" c> <meta. http-equiv="description" c> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> This is the FileUpload of Struts 2 page. <br> <s:form. action = "upload.action" enctype = "multipart/form-data"> <input type = "file" name = "fileUpload"></input> <input type = "submit" value = "提交"></input> </s:form> </body> </html>
（6）配置struts-fileupload.xml文件，代码如下：
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <!-- 如果要上传中文名称的文件，将"struts.i18n.encoding"的值设置为GBK --> <constant name="struts.i18n.encoding" value="GBK"></constant> <package name="fileupload" extends = "struts-default" namespace = "/ch4"> <action name="upload" class = "com.gxa.edu.struts2.ch4.action.FileUploadAction" method = "upload"> <param name="fileSavePath">/upload</param> <result>/ch4/upload.jsp</result> <result name = "input">/ch4/upload.jsp</result> </action> </package> </struts>
