在Struts2里面提供了内置的处理文件上传的支持。在正确的配置好的前提下，上传的文件会被传到action里面去。支持单文件和多文件上传。当一个文件被上传的时候，会先把上传的文件存储到一个临时目录中，上传的文件可以通过action类来处理或者移到其他地方来保证数据不会丢失。
Struts2使用附加的类库来处理文件的转换，需要我们单独加入到我们的project中
|-Commons-FileUpload
|-Commons-IO
在defaultStack里面，包含了一个默认的类（org.apache.struts2.interceptor.FileUploadInterceptor）来处理文件上传。
用来上传文件的表单，需要加上encoding的方式，如下代码：
<%@ page language="java" 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><title>表单界面</title></head><body> ???<p>文件上传页面/p> ???<s:form action="doUpload" method="post" enctype="multipart/form-data"> ???????<s:file name="upload" label="文件"/> ???????<s:submit value="上传"/> ???</s:form></body></html>
在fileUpload拦截器会使用注入的方式把上传的文件关联到action类里面去。我们需要在action类里面提供以下三个setter方法。
package com.fuwh.model;import java.io.File;import java.util.Date;import org.apache.commons.io.FileUtils;import com.opensymphony.xwork2.ActionSupport;import com.sun.jmx.snmp.Timestamp;public class UploadAction extends ActionSupport{ ???????private static final long serialVersionUID = 1L; ???????//form表单里面的的文件名字要 ???private File file; ???//form表单里面的的文件名字+FileName ???private String fileFileName; ???//form表单里面的的文件名字+ContentType ???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; ???} ???@Override ???public String execute() throws Exception { ???????// TODO Auto-generated method stub ???????System.out.println("default execute method!!!"); ???????System.out.println(file.getPath()+" "+file.getName()); ???????System.out.println(fileFileName); ???????System.out.println(fileContentType); ???????????????File destFile=new File("D:"+File.separator+fileFileName); ???????System.out.println(destFile.getPath()); ???????//复制图片 ???????FileUtils.copyFile(file, destFile); ???????????????return SUCCESS; ???} ???????}配置文件代码
<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC ???"-//Apache Software Foundation//DTD Struts Configuration 2.5//EN" ???"http://struts.apache.org/dtds/struts-2.5.dtd"><struts> ???<!-- 开启debug模式，会自动加载配置文件等等，不用每次更改了配置文件就去重新启动下服务器 --> ???<constant name="struts.devMode" value="true" /> ???????<!-- 配置action --> ???<package name="uploadAction" extends="struts-default"> ???????<action name="uploadAction" class="com.fuwh.model.UploadAction"> ???????????<result name="success">success.jsp</result> ???????????<!-- 必须要有input --> ???????????<result name="input">index.jsp</result> ???????</action> ???</package></struts>
上传多个文件
当需要上传多个文件的时候，基本上和单个文件是一样的处理，首先在表单的地方写多个文件选择框。可以选择使用不同的名字，则在action类里面也写三个，系统就会处理三次文件的上传，还有一种选择就是在表单里面使用相同的名字，则在action类里面用一个文件数组的方式来接收。还可以选择使用List来接收
array数组的方式
<%@ page language="java" 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><title>表单界面</title></head><body> ???<p style="color: red">多个文件上传页面</p> ???<s:form action="uploadAction" method="post" enctype="multipart/form-data"> ???????<s:file name="file" label="文件1"/> ???????<s:file name="file" label="文件2"/> ???????<s:file name="file" label="文件3"/> ???????<s:submit value="上传"/> ???</s:form></body></html>
package com.fuwh.model;import java.io.File;import org.apache.commons.io.FileUtils;import com.opensymphony.xwork2.ActionSupport;public class UploadAction extends ActionSupport{ ???????private static final long serialVersionUID = 1L; ???????//form表单里面的的文件名字要 ???private File[] file; ???//form表单里面的的文件名字+FileName ???private String[] fileFileName; ???//form表单里面的的文件名字+ContentType ???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; ???} ???@Override ???public String execute() throws Exception { ???????// TODO Auto-generated method stub ???????for (int i = 0; i < file.length; i++) { ???????????File destFile=new File("D:"+File.separator+fileFileName[i]); ???????????System.out.println(destFile.getPath()); ???????????//复制图片 ???????????FileUtils.copyFile(file[i], destFile); ???????} ???????return SUCCESS; ???} ???????}List的方式
package com.fuwh.model;import java.io.File;import java.util.List;import com.opensymphony.xwork2.ActionSupport;public class UploadAction extends ActionSupport{ ???????private static final long serialVersionUID = 1L; ???????//form表单里面的的文件名字要file ???private List<File> uploads; ???//form表单里面的的文件名字+FileName ???private List<String> uploadNames; ???//form表单里面的的文件名字+ContentType ???private List<String> uploadContentTypes; ???public List<File> getFile() { ???????return uploads; ???} ???public void setFile(List<File> uploads) { ???????this.uploads = uploads; ???} ???public List<String> getFileFileName() { ???????return uploadNames; ???} ???public void setFileFileName(List<String> uploadNames) { ???????this.uploadNames = uploadNames; ???} ???public List<String> getFileContentType() { ???????return uploadContentTypes; ???} ???public void setFileContentType(List<String> uploadContentTypes) { ???????this.uploadContentTypes = uploadContentTypes; ???} ???@Override ???public String execute() throws Exception { ???????// TODO Auto-generated method stub ???????for (File file : uploads) { ???????????System.out.println(file); ???????} ???????????????for (String string : uploadContentTypes) { ???????????System.out.println(string); ???????} ???????????????for (String string : uploadNames) { ???????????System.out.println(string); ???????} ???????return SUCCESS; ???} ???}文件下载
<%@ page language="java" 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><title>表单界面</title></head><body> ???<a href="download1">文件下载1</a><br/> ???<a href="download2">文件下载2</a><br/></body></html>
<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC ???"-//Apache Software Foundation//DTD Struts Configuration 2.5//EN" ???"http://struts.apache.org/dtds/struts-2.5.dtd"><struts> ???<!-- 开启debug模式，会自动加载配置文件等等，不用每次更改了配置文件就去重新启动下服务器 --> ???<constant name="struts.devMode" value="true" /> ???????<!-- 配置action --> ???<package name="downLoad" extends="struts-default"> ???????<action name="download1" class="com.fuwh.model.DownloadAction"> ???????????<!-- ????????????????inputPath:为action中的inputPath注入值 ???????????????contentType：设置返回的mime类型，默认是text/plain ???????????????contentLength:返回的流的字节数 ???????????????inputName:chain action中的InputStream的名字，默认是inputStream ???????????????contentDisposition：下载的文件的名字 ???????????????bufferSize:input 到output的事后的缓存的大小 ???????????????allowCaching：是否允许缓存，默认是true ???????????????contentCharSet:设置字符编码方式,如果设置一个字符串的话，则会在contentType头文件中 ???????????????添加";charset=value" ????????????--> ???????????<param name="inputPath">/struts.gif</param> ???????????<result name="success" type="stream"> ???????????????<param name="contentType">image/gif</param> ???????????????<param name="inputName">inputStream</param> ???????????????<param name="contentDisposition">filename="struts.gif"</param> ???????????????<param name="bufferSize">4096</param> ???????????</result> ???????</action> ???????<action name="download2" class="com.fuwh.model.DownloadAction"> ???????????<param name="inputPath">a.zip</param> ???????????<result name="success" type="stream"> ???????????????<param name="contentType">application/zip</param> ???????????????<param name="inputName">inputStream</param> ???????????????<param name="contentDisposition">attachment;filename="abcd.zip"</param> ???????????????<param name="bufferSize">4096</param> ???????????</result> ???????</action> ???</package></struts>
package com.fuwh.model;import java.io.InputStream;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;public class DownloadAction extends ActionSupport{ ???????private static final long serialVersionUID = 1L; ???????private String inputPath; ???????????public String getInputPath() { ???????return inputPath; ???} ???public void setInputPath(String inputPath) { ???????this.inputPath = inputPath; ???} ???//必须有这个方法 ???public InputStream getInputStream() throws Exception { ???????System.out.println("execute getInputStream method"); ???????System.out.println(inputPath); ???????return ServletActionContext.getServletContext().getResourceAsStream(inputPath); ???}}常用配置
在struts2里面还提供了一些常用的配置来控制文件的上传。下面三个就是在default.properties中的默认配置
|-struts.multipart.parser=jakarta
|-struts.multipart.saveDir=
|-struts.multipart.maxSize=2097152 //最大上传文件大小（约2M）（是整个请求的大小）
<?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="1000000" /> ???...</struts>
还可以通过配置fileUpload这个拦截器，来控制允许上传的文件类型。
<action name="doUpload" class="com.example.UploadAction"> ???<interceptor-ref name="basicStack"/> ???<interceptor-ref name="fileUpload"> ???????<param name="allowedTypes">text/plain</param> ???</interceptor-ref> ????<interceptor-ref name="validation"/> ???<interceptor-ref name="workflow"/> ????<result name="success">good_result.jsp</result></action>
除了使用struts2里面的default.properties还有另外一种配置限制上传文件的大小的方式。
default.properties的方式主要是出于安全的考虑，防止有人恶意的上传超大文件来占用服务器的空间，这个默认是2M，最大可以设置2G。但是这是整个请求的大小，而不是单个上传的文件的大小，另外一种控制方式，通过拦截器的参数设置，来达到控制单个文件的大小的效果。
<?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="1000000" /> <action name="doUpload" class="com.example.UploadAction"> <interceptor-ref name="basicStack"/> <interceptor-ref name="fileUpload"> <param name="maximumSize">500000</param> </interceptor-ref> <interceptor-ref name="validation"/> <interceptor-ref name="workflow"/> <result name="success">good_result.jsp</result> </action></struts>
在控制上传文件类型的时候，也是有两种方式的，一种就是前面提到的配置的方式(声明式)，另一种就是编程式。
<action name="doUpload" class="com.example.UploadAction"> <interceptor-ref name="basicStack"/> <interceptor-ref name="fileUpload"> <param name="allowedTypes">image/jpeg,image/gif</param> </interceptor-ref> <interceptor-ref name="validation"/> <interceptor-ref name="workflow"/> <result name="success">good_result.jsp</result></action>
Struts2--文件上传与下载
原文地址：http://www.cnblogs.com/wangsicongde/p/7574264.html