（八）Struts2 文件上传和下载

所有的学习我们必须先搭建好Struts2的环境（1、导入对应的jar包，2、web.xml，3、struts.xml）

第一节：Struts2 文件上传

Struts2 文件上传基于Struts2 拦截器实现；

Struts2 文件上传使用的是fileupload 组件；

Form 配置enctype="multipart/form-data"；（这样就是以二进制来上传的）

Struts2 获取上传文件：name (name 是文件表单的name)

Struts2 获取上传文件名：name+FileName；

Struts2 获取上传文件的类型：name+ContentType；

例子：

struts.xml

<?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>

    <package name="manager" extends="struts-default">

        <action name="upload" class="com.wishwzp.action.FileUploadAction">

            <result name="success">/success.jsp</result>

        </action>

    </package>

</struts>

FileUploadAction.java

 package com.wishwzp.action;

 import java.io.File;

 import org.apache.commons.io.FileUtils;

 import com.opensymphony.xwork2.ActionSupport;

 public class FileUploadAction extends ActionSupport{

     /**

      *

      */

     private static final long serialVersionUID = 1L;

     // 文件(这里的文件名必须要和前端的文件：<input type="file" name="wishwzp"/><br/>name一样)

     private File wishwzp; 

     // 文件名（name+FileName）

     private String wishwzpFileName;  

     // 文件类型（name+ContentType）

     private String wishwzpContentType;  

     public File getwishwzp() {

         return wishwzp;

     }

     public void setwishwzp(File wishwzp) {

         this.wishwzp = wishwzp;

     }

     public String getwishwzpFileName() {

         return wishwzpFileName;

     }

     public void setwishwzpFileName(String wishwzpFileName) {

         this.wishwzpFileName = wishwzpFileName;

     }

     public String getwishwzpContentType() {

         return wishwzpContentType;

     }

     public void setwishwzpContentType(String wishwzpContentType) {

         this.wishwzpContentType = wishwzpContentType;

     }

     @Override

     public String execute() throws Exception {

         System.out.println("文件名："+wishwzpFileName);

         System.out.println("文件类型："+wishwzpContentType);

         //上传到C盘中

         String filePath="C:/"+wishwzpFileName;

         //保存文件添加到文件中

         File saveFile=new File(filePath);

         //将wishwzp文件拷到saveFile中，这样数据就到C盘中了

         FileUtils.copyFile(wishwzp, saveFile);

         return SUCCESS;

     }

 }

fileupload.jsp

 <%@ page language="java" contentType="text/html; charset=UTF-8"

     pageEncoding="UTF-8"%>

 <%@taglib prefix="s" uri="/struts-tags" %>

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

 <html>

 <head>

 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

 <title>Insert title here</title>

 </head>

 <body>

 <!-- 这里enctype="multipart/form-data就是将数据以二进制上传 -->

 <form action="upload" method="post" enctype="multipart/form-data">

     文件：<input type="file" name="wishwzp"/><br/>

     <input type="submit" value="提交"/>

 </form>

 </body>

 </html>

success.jsp

 <%@ page language="java" contentType="text/html; charset=UTF-8"

     pageEncoding="UTF-8"%>

 <%@taglib prefix="s" uri="/struts-tags" %>

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

 <html>

 <head>

 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

 <title>Insert title here</title>

 </head>

 <body>

 文件上传成功！

 </body>

 </html>

第二节：配置文件的大小及类型

配置可以上传哪些文件的信息以及最大上传的大小

<param name="allowedTypes">image/bmp,image/x-png,image/gif,image/jpg,image/jpeg</param>

例子：

struts.xml

 <?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>

     <package name="manager" extends="struts-default">

         <action name="upload" class="com.wishwzp.action.FileUploadAction">

             <result name="success">/success.jsp</result>

             <result name="input">/fileupload.jsp</result>

              <interceptor-ref name="fileUpload">

                 <param name="allowedTypes">image/bmp,image/x-png,image/gif,image/jpg,image/jpeg</param>

                 <param name="maximumSize">81101</param>

             </interceptor-ref>

             <interceptor-ref name="defaultStack"></interceptor-ref>

         </action>

     </package>

 </struts>

前端页面文件错误表达式：

<s:fielderror></s:fielderror>

例子：

fileupload.jsp

 <%@ page language="java" contentType="text/html; charset=UTF-8"

     pageEncoding="UTF-8"%>

 <%@taglib prefix="s" uri="/struts-tags" %>

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

 <html>

 <head>

 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

 <title>Insert title here</title>

 </head>

 <body>

 <s:fielderror></s:fielderror>

 <!-- 这里enctype="multipart/form-data就是将数据以二进制上传 -->

 <form action="upload" method="post" enctype="multipart/form-data">

     文件：<input type="file" name="wishwzp"/><br/>

     <input type="submit" value="提交"/>

 </form>

 </body>

 </html>

第三节：大文件上传

Struts2 文件上传大小默认是2M；

例子：

struts.xml

 <?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>

     <!-- 上传大小配置 -->

     <constant name="struts.multipart.maxSize" value="20000000"></constant>

     <package name="manager" extends="struts-default">

         <action name="upload" class="com.wishwzp.action.FileUploadAction">

             <result name="success">/success.jsp</result>

             <result name="input">/fileupload.jsp</result>

         </action>

     </package>

 </struts>

第四节：多文件上传

strutsl.xml

 <?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>

         <package name="manager" extends="struts-default">

         <action name="uploads" class="com.wishwzp.action.FilesUploadAction">

             <result name="success">/success.jsp</result>

             <result name="input">/filesupload.jsp</result>

         </action>

     </package>

 </struts>

FilesUploadAction.java

 package com.wishwzp.action;

 import java.io.File;

 import org.apache.commons.io.FileUtils;

 import com.opensymphony.xwork2.ActionSupport;

 public class FilesUploadAction extends ActionSupport{

     /**

      *

      */

     private static final long serialVersionUID = 1L;

     // 文件(这里的文件名必须要和前端的文件：<input type="file" name="wishwzp"/><br/>name一样)

     private File[] wishwzp; 

     // 文件名（name+FileName）

     private String[] wishwzpFileName; 

     // 文件类型（name+ContentType）

     private String[] wishwzpContentType; 

     public File[] getwishwzp() {

         return wishwzp;

     }

     public void setwishwzp(File[] wishwzp) {

         this.wishwzp = wishwzp;

     }

     public String[] getwishwzpFileName() {

         return wishwzpFileName;

     }

     public void setwishwzpFileName(String[] wishwzpFileName) {

         this.wishwzpFileName = wishwzpFileName;

     }

     public String[] getwishwzpContentType() {

         return wishwzpContentType;

     }

     public void setwishwzpContentType(String[] wishwzpContentType) {

         this.wishwzpContentType = wishwzpContentType;

     }

     @Override

     public String execute() throws Exception {

         for(int i=0;i<wishwzp.length;i++){

             System.out.println("文件名："+wishwzpFileName[i]);

             System.out.println("文件类型："+wishwzpContentType[i]);

             //上传到C盘中

             String filePath="C:/"+wishwzpFileName[i];

             //保存文件添加到文件中

             File saveFile=new File(filePath);

             //将wishwzp文件拷到saveFile中，这样数据就到C盘中了

             FileUtils.copyFile(wishwzp[i], saveFile);

         }

         return SUCCESS;

     }

 }

filesupload.jsp

 <%@ page language="java" contentType="text/html; charset=UTF-8"

     pageEncoding="UTF-8"%>

 <%@taglib prefix="s" uri="/struts-tags" %>

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

 <html>

 <head>

 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

 <title>Insert title here</title>

 </head>

 <body>

 <s:fielderror></s:fielderror>

 <form action="uploads" method="post" enctype="multipart/form-data">

     文件1：<input type="file" name="wishwzp"/><br/>

     文件2：<input type="file" name="wishwzp"/><br/>

     文件3：<input type="file" name="wishwzp"/><br/>

     <input type="submit" value="提交"/>

 </form>

 </body>

 </html>

第五节：Struts2 文件下载

返回的是文件流

<param name="contentDisposition">attachment;filename=${fileName}</param>

InputStream getInputStream()

struts.xml

 <?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>

     <constant name="struts.multipart.maxSize" value="20000000"></constant>

     <package name="manager" extends="struts-default">

         <action name="download" class="com.wishwzp.action.FileDownloadAction">

             <result type="stream">

                 <param name="contentDisposition">attachment;filename=${fileName}</param>

             </result>

         </action>

     </package>

 </struts>

FileDownloadAction.java

 package com.wishwzp.action;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.InputStream;

 import com.opensymphony.xwork2.ActionSupport;

 public class FileDownloadAction extends ActionSupport{

     /**

      *

      */

     private static final long serialVersionUID = 1L;

     private String fileName;

     public String getFileName() throws Exception{

         fileName=new String(fileName.getBytes(),"ISO8859-1");

         return fileName;

     }

     public void setFileName(String fileName) {

         this.fileName = fileName;

     }

     public InputStream getInputStream()throws Exception{

         File file=new File("C:/美女1.jpg");

         this.fileName="美女1号";

         return new FileInputStream(file);

     }

 }

filedownload.jsp

 <%@ page language="java" contentType="text/html; charset=UTF-8"

     pageEncoding="UTF-8"%>

 <%@taglib prefix="s" uri="/struts-tags" %>

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

 <html>

 <head>

 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

 <title>Insert title here</title>

 </head>

 <body>

 <a href="download">文件下载</a>

 </body>

 </html>