struts2文件上传

上传原理：

回顾：

之前不使用框架，导入commons-fileupload.jar和commons-io.jar

首先进行解析，将request对应参数转为File对象：

使用factory：

request.setCharacterEncoding("UTF-8"); 

DiskFileItemFactory factory = new DiskFileItemFactory(); 

//设置上传工厂的限制 

factory.setSizeThreshold(1024 * 1024 * 20); 

factory.setRepository(new File(request.getRealPath("/"))); 

//创建一个上传文件的ServletFileUpload对象 

ServletFileUpload upload = new ServletFileUpload(factory); 

//设置最大的上传限制 

upload.setSizeMax(1024 * 1024 * 20); 

//处理HTTP请求，items是所有的表单项 

List items = upload.parseRequest(request); 

//遍历所有的表单项 

for(Iterator it = items.iterator();it.hasNext();){ 

FileItem item = (FileItem) it.next(); 

if(item.isFormField()){ 

String name = item.getFieldName(); 

String value = item.getString("GBK"); 

out.println("表单域的name=value对为：" + name + "=" + value); 

}else{ 
    .......
} 

} 

不使用factory：

DiskFileUpload diskFileUpload = new DiskFileUpload();
        try{
            List<FileItem> list = diskFileUpload.parseRequest(request);
            
            out.println("遍历所有的FileItem...<br/>");
            for(FileItem fileItem : list){
                if(fileItem.isFormField()){
                    if("description1".equals(fileItem.getFieldName())){
                        out.println("遍历到description1 ... <br/>");
                        description1 = new String(fileItem.getString().getBytes(),"UTF-8");
                    }
                    if("description2".equals(fileItem.getFieldName())){
                        out.println("遍历到description2 ... <br/>");
                        description2 = new String(fileItem.getString().getBytes(),"UTF-8");
                    }
                }else{
                    ......
                }
            }
        }catch(Exception e){
          ......
        }

然后，获取对应参数构建InputStream和OutputStream，进行IO读写操作

//取得文件域的表单域名 

String fieldName = item.getFieldName(); 

//取得文件名 

String fileName = item.getName(); 

//取得文件类型 

String contentType = item.getContentType(); 

out.println("表单域的name=value对为：" + fieldName + "=" + fileName); 

//以原文件名作为新的文件名 

FileOutputStream fos = new FileOutputStream(request.getRealPath("/") + fileName); 

//如果上传文件域对应文件的内容已经在内存中 

if(item.isInMemory()){ 

fos.write(item.get()); 

}else{ 

//获取上传文件内容的输入流 

InputStream is = item.getInputStream(); 

byte[] buffer = new byte[1024]; 

int len; 

//读取上传文件的内容，并将其写入服务器的文件中 

while((len = is.read(buffer)) > 0){ 

fos.write(buffer,0,len); 

} 

//关闭输入流和输出流 

is.close(); 

fos.close(); 

} 

struts2的文件上传与之前的文件上传有什么区别呢？

其实原理都是一样的。不过是struts2将前面解析file控件传递过来的内容解析自动解析成了对应的对象，并且自动赋值给了action内的对应对象。

    >该解析操作封装在一个默认的拦截器中。fileUpload拦截器

      <interceptor-ref name="fileUpload"/>

       该拦截器有三个参数：

       maxmumSize ：最大上传字节，默认为2M

       allowedTypes：允许上传的类型，用逗号分隔，例如：text/html

       allowedExtensions：允许上传文件的后缀名，用逗号分隔，例如：.html

   >自动赋值给action中对应属性，两个要求：

    调用默认拦截器组：<interceptor-ref name="defaultStack" />

    jsp和action中的属性名要一致，举个例子说明吧：

jsp中： 
<s:file name="upload" label="File"/>
action中属性：
private File upload;
private String uploadFileName;
private String uploadContentType;
对应getter和setter方法

单个文件上传：

package com.upload;

import java.io.*;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;



public class UploadAction extends ActionSupport{
    private File file;
    private String fileFileName;
    private String filecontentType;
    public File getFile() {
        return file;
    }
    public void setFile(File file) {
        this.file = file;
    }
    public String getFileFileName() {
        return fileFileName;
    }
    public void setFileFileName(String fileFileName) {
        this.fileFileName = fileFileName;
    }
    public String getFilecontentType() {
        return filecontentType;
    }
    public void setFilecontentType(String filecontentType) {
        this.filecontentType = filecontentType;
    }
    
    public String execute(){
        InputStream is=null;
        OutputStream os=null;
        try {
            is = new FileInputStream(file);
            String path=ServletActionContext.getServletContext().getRealPath("upload");
            File newFile=new File(path,this.getFileFileName());
            os=new FileOutputStream(newFile);
            byte[] b=new byte[1024];
            int len=0;
            while((len=is.read(b))!=-1){
                os.write(b, 0, len);
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }        
        try {
                
            if(is!=null)is.close();
            if(os!=null)os.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        return SUCCESS;
    }

}

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ 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 'login.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>
    <s:form action="upload" method="post" enctype="multipart/form-data" namespace="/">
    <s:file name="file"></s:file>
    <s:submit label="OK"></s:submit>
    </s:form>
  </body>
</html>

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@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 'success.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>
    <s:iterator var="t" value="#request.fileName">
      <s:property value="t"/>
    </s:iterator>
    <!--
    <s:property value="#request.fileFileName"/> <br/>
    -->
    <!-- 该对象既被存放在值栈中又被存放在request对象内 -->
    <!--<s:property value="fileFileName"/> -->
  </body>
</html>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
    "http://struts.apache.org/dtds/struts-2.3.dtd">
    
<struts>

    <package name="default" extends="struts-default" namespace="/">
       <action name="upload" class="com.upload.UploadAction">
          <interceptor-ref name="fileUpload"/>
          <interceptor-ref name="defaultStack"></interceptor-ref>
          <result>/jsp/upload/success.jsp</result>
       </action>
       
       <action name="fileupload" class="com.upload.FilesUploadAction">
          <interceptor-ref name="fileUpload"/>
          <interceptor-ref name="defaultStack"></interceptor-ref>
          <result>/jsp/upload/success.jsp</result>
       </action>
    </package>
  
</struts>

上传多个文件：

struts.xml和success.xml共用

package com.upload;

import java.io.*;
import java.util.*;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;


public class FilesUploadAction extends ActionSupport {
    private List<File> file;
    private List<String> fileFileName;
    private List<String> fileContentType;
    public List<File> getFile() {
        return file;
    }
    public void setFile(List<File> file) {
        this.file = file;
    }
    public List<String> getFileFileName() {
        return fileFileName;
    }
    public void setFileFileName(List<String> fileFileName) {
        this.fileFileName = fileFileName;
    }
    public List<String> getFileContentType() {
        return fileContentType;
    }
    public void setFileContentType(List<String> fileContentType) {
        this.fileContentType = fileContentType;
    }
    
    public String execute(){
        String root=ServletActionContext.getServletContext().getRealPath("/")+"/upload";
        List<File> fy=file;
        InputStream is=null;
        OutputStream os=null;
        
        for(int i=0;i<fy.size();i++){
            
            try {
                byte[] buffer=new byte[1024];
                is=new FileInputStream(file.get(i));
                File newFile=new File(root,fileFileName.get(i));
                os=new FileOutputStream(newFile);
                int len=0;
                while((len=is.read(buffer))!=-1){
                    os.write(buffer,0,len);
                    os.flush();
                }
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                is=null;
                os=null;
            }
        }
        return "success";
    }

}


<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ 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 'login.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>
    <s:form action="fileupload" method="post" enctype="multipart/form-data" namespace="/">
    <s:file name="file"></s:file><br/>
    <s:file name="file"></s:file><br/>
    <s:file name="file"></s:file>
    <s:submit label="OK"></s:submit>
    </s:form>
  </body>
</html>