（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

 1 package com.wishwzp.action;
 2 
 3 import java.io.File;
 4 
 5 import org.apache.commons.io.FileUtils;
 6 
 7 import com.opensymphony.xwork2.ActionSupport;
 8 
 9 public class FileUploadAction extends ActionSupport{
10 
11     /**
12      * 
13      */
14     private static final long serialVersionUID = 1L;
15     
16     // 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)
17     private File wishwzp; 
18     
19     // 文件名（name+FileName）
20     private String wishwzpFileName;  
21     
22     // 文件类型（name+ContentType）
23     private String wishwzpContentType;  
24 
25     public File getwishwzp() {
26         return wishwzp;
27     }
28 
29     public void setwishwzp(File wishwzp) {
30         this.wishwzp = wishwzp;
31     }
32 
33     public String getwishwzpFileName() {
34         return wishwzpFileName;
35     }
36 
37     public void setwishwzpFileName(String wishwzpFileName) {
38         this.wishwzpFileName = wishwzpFileName;
39     }
40 
41     public String getwishwzpContentType() {
42         return wishwzpContentType;
43     }
44 
45     public void setwishwzpContentType(String wishwzpContentType) {
46         this.wishwzpContentType = wishwzpContentType;
47     }
48 
49     @Override
50     public String execute() throws Exception {
51         System.out.println("文件名："+wishwzpFileName);
52         System.out.println("文件类型："+wishwzpContentType);
53         //上传到C盘中
54         String filePath="C:/"+wishwzpFileName;
55         //保存文件添加到文件中
56         File saveFile=new File(filePath);
57         //将wishwzp文件拷到saveFile中，这样数据就到C盘中了
58         FileUtils.copyFile(wishwzp, saveFile);
59         return SUCCESS;
60     }
61     
62     
63     
64 
65 }

fileupload.jsp

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <%@taglib prefix="s" uri="/struts-tags" %>
 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 5 <html>
 6 <head>
 7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 8 <title>Insert title here</title>
 9 </head>
10 <body>
11 <!-- 这里enctype="multipart/form-data就是将数据以二进制上传 -->
12 <form action="upload" method="post" enctype="multipart/form-data">
13     文件：<input type="file" name="wishwzp"/><br/>
14     <input type="submit" value="提交"/>
15 </form>
16 </body>
17 </html>

success.jsp

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <%@taglib prefix="s" uri="/struts-tags" %>
 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 5 <html>
 6 <head>
 7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 8 <title>Insert title here</title>
 9 </head>
10 <body>
11 文件上传成功！
12 </body>
13 </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

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE struts PUBLIC
 3     "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
 4     "http://struts.apache.org/dtds/struts-2.0.dtd">
 5 
 6 <struts>
 7     
 8     <package name="manager" extends="struts-default">
 9         
10         <action name="upload" class="com.wishwzp.action.FileUploadAction">
11             <result name="success">/success.jsp</result>
12             <result name="input">/fileupload.jsp</result>
13             
14              <interceptor-ref name="fileUpload">
15                 <param name="allowedTypes">image/bmp,image/x-png,image/gif,image/jpg,image/jpeg</param>
16                 <param name="maximumSize">81101</param>
17             </interceptor-ref>
18             
19             <interceptor-ref name="defaultStack"></interceptor-ref>
20              
21         </action>
22         
23     </package>
24  
25 </struts>

前端页面文件错误表达式：

<s:fielderror></s:fielderror>

例子：

fileupload.jsp

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <%@taglib prefix="s" uri="/struts-tags" %>
 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 5 <html>
 6 <head>
 7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 8 <title>Insert title here</title>
 9 </head>
10 <body>
11 <s:fielderror></s:fielderror>
12 <!-- 这里enctype="multipart/form-data就是将数据以二进制上传 -->
13 <form action="upload" method="post" enctype="multipart/form-data">
14     文件：<input type="file" name="wishwzp"/><br/>
15     <input type="submit" value="提交"/>
16 </form>
17 </body>
18 </html>

第三节：大文件上传

Struts2 文件上传大小默认是2M；

例子：

struts.xml

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE struts PUBLIC
 3     "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
 4     "http://struts.apache.org/dtds/struts-2.0.dtd">
 5 
 6 <struts>
 7     
 8     <!-- 上传大小配置 -->
 9     <constant name="struts.multipart.maxSize" value="20000000"></constant>
10     
11     <package name="manager" extends="struts-default">
12         
13         <action name="upload" class="com.wishwzp.action.FileUploadAction">
14             <result name="success">/success.jsp</result>
15             <result name="input">/fileupload.jsp</result>
16             
17         </action>
18         
19     </package>
20  
21 </struts>

第四节：多文件上传

strutsl.xml

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE struts PUBLIC
 3     "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
 4     "http://struts.apache.org/dtds/struts-2.0.dtd">
 5 
 6 <struts>
 7         <package name="manager" extends="struts-default">
 8         <action name="uploads" class="com.wishwzp.action.FilesUploadAction">
 9             <result name="success">/success.jsp</result>
10             <result name="input">/filesupload.jsp</result>
11         </action>
12         
13         
14     </package>
15  
16 </struts>

FilesUploadAction.java

 1 package com.wishwzp.action;
 2 
 3 import java.io.File;
 4 
 5 import org.apache.commons.io.FileUtils;
 6 
 7 import com.opensymphony.xwork2.ActionSupport;
 8 
 9 public class FilesUploadAction extends ActionSupport{
10 
11     /**
12      * 
13      */
14     private static final long serialVersionUID = 1L;
15     
16     // 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)
17     private File[] wishwzp; 
18     
19     // 文件名（name+FileName）
20     private String[] wishwzpFileName; 
21     
22     // 文件类型（name+ContentType）
23     private String[] wishwzpContentType; 
24 
25 
26     public File[] getwishwzp() {
27         return wishwzp;
28     }
29 
30 
31     public void setwishwzp(File[] wishwzp) {
32         this.wishwzp = wishwzp;
33     }
34 
35 
36     public String[] getwishwzpFileName() {
37         return wishwzpFileName;
38     }
39 
40 
41     public void setwishwzpFileName(String[] wishwzpFileName) {
42         this.wishwzpFileName = wishwzpFileName;
43     }
44 
45 
46     public String[] getwishwzpContentType() {
47         return wishwzpContentType;
48     }
49 
50 
51     public void setwishwzpContentType(String[] wishwzpContentType) {
52         this.wishwzpContentType = wishwzpContentType;
53     }
54 
55 
56     @Override
57     public String execute() throws Exception {
58         for(int i=0;i<wishwzp.length;i++){
59             System.out.println("文件名："+wishwzpFileName[i]);
60             System.out.println("文件类型："+wishwzpContentType[i]);
61             //上传到C盘中
62             String filePath="C:/"+wishwzpFileName[i];
63             //保存文件添加到文件中
64             File saveFile=new File(filePath);
65             //将wishwzp文件拷到saveFile中，这样数据就到C盘中了
66             FileUtils.copyFile(wishwzp[i], saveFile);            
67         }
68         return SUCCESS;
69     }
70 
71 }

filesupload.jsp

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <%@taglib prefix="s" uri="/struts-tags" %>
 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 5 <html>
 6 <head>
 7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 8 <title>Insert title here</title>
 9 </head>
10 <body>
11 <s:fielderror></s:fielderror>
12 <form action="uploads" method="post" enctype="multipart/form-data">
13     文件1：<input type="file" name="wishwzp"/><br/>
14     文件2：<input type="file" name="wishwzp"/><br/>
15     文件3：<input type="file" name="wishwzp"/><br/>
16     <input type="submit" value="提交"/>
17 </form>
18 </body>
19 </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

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE struts PUBLIC
 3     "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
 4     "http://struts.apache.org/dtds/struts-2.0.dtd">
 5 
 6 <struts>
 7     
 8     <constant name="struts.multipart.maxSize" value="20000000"></constant>
 9     
10     <package name="manager" extends="struts-default">
11         <action name="download" class="com.wishwzp.action.FileDownloadAction">
12             <result type="stream">
13                 <param name="contentDisposition">attachment;filename=${fileName}</param>
14             </result>
15         </action>
16         
17     </package>
18  
19 </struts>

FileDownloadAction.java

 1 package com.wishwzp.action;
 2 
 3 import java.io.File;
 4 import java.io.FileInputStream;
 5 import java.io.InputStream;
 6 
 7 import com.opensymphony.xwork2.ActionSupport;
 8 
 9 public class FileDownloadAction extends ActionSupport{
10 
11     /**
12      * 
13      */
14     private static final long serialVersionUID = 1L;
15     
16     private String fileName;
17 
18     public String getFileName() throws Exception{
19         fileName=new String(fileName.getBytes(),"ISO8859-1");
20         return fileName;
21     }
22 
23     public void setFileName(String fileName) {
24         this.fileName = fileName;
25     }
26     
27     public InputStream getInputStream()throws Exception{
28         File file=new File("C:/美女1.jpg");
29         this.fileName="美女1号";
30         return new FileInputStream(file);
31     }
32 
33 }

filedownload.jsp

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <%@taglib prefix="s" uri="/struts-tags" %>
 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 5 <html>
 6 <head>
 7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 8 <title>Insert title here</title>
 9 </head>
10 <body>
11 <a href="download">文件下载</a>
12 </body>
13 </html>

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原文地址：https://www.cnblogs.com/wishwzp/p/5472604.html