Struts2中的文件上传
package com.test;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.InputStream;import java.io.OutputStream;import org.apache.commons.io.IOUtils;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;public class UploadAction extends ActionSupport {/** * */private static final long serialVersionUID = 8926090411591986144L;private String allowTypes ;private int maximumSize ;private File upload;private String uploadFileName;private String uploadContentType;private String savePath;public File getUpload() {return upload;}public void setUpload(File upload) {this.upload = upload;}public String getUploadFileName() {return uploadFileName;}public void setUploadFileName(String uploadFileName) {this.uploadFileName = uploadFileName;}public String getUploadContentType() {return uploadContentType;}public void setUploadContentType(String uploadContentType) {this.uploadContentType = uploadContentType;}public String getSavePath() {return savePath;}public void setSavePath(String savePath) {this.savePath = savePath;}public String getAllowTypes() {return allowTypes;}public void setAllowTypes(String allowTypes) {this.allowTypes = allowTypes;}public int getMaximumSize() {return maximumSize;}public void setMaximumSize(int maximumSize) {this.maximumSize = maximumSize;}@Overridepublic String execute() throws Exception {String checkUploadType = checkUploadType();if(checkUploadType != null) {this.addFieldError("upload", "上传文件类型只能是:" + allowTypes);return checkUploadType;} String checkSize = checkUploadSize();if(checkSize != null) {this.addFieldError("upload", "上传文件大小大于" + maximumSize);return checkSize;}String saveDir = ServletActionContext.getRequest().getSession().getServletContext().getRealPath(savePath);OutputStream out = new FileOutputStream(saveDir + "\\" + uploadFileName);InputStream in = new FileInputStream(upload);IOUtils.copy(in, out);return SUCCESS;}public String checkUploadSize() {long uploadLength = upload.length();if(uploadLength > maximumSize) {return INPUT;} else {return null;}}public String checkUploadType() {String result = INPUT;String[] types = allowTypes.split(",");for (String str : types) {if(str.equals(uploadContentType)) {return null;}}return result;}}?<action name="uploadAction" name="code"><%@ 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:form action="uploadAction.action" method="post" enctype="multipart/form-data"><s:file name="upload" label="选择文件"></s:file><s:submit value="上传"></s:submit></s:form></body></html>?
? 上面是手动拦截的上传文件类型和上传文件大小，没有使用拦截器，下面写个例子是使用的struts2里面默认配置的拦截器fileUpload实现上传的拦截。
代码如下：需要将struts.xml进行配置
<action name="uploadAction" class="com.test.UploadAction"><param name="savePath">/upload</param><interceptor-ref name="fileUpload"><param name="maximumSize">10000</param><param name="allowedTypes">image/pjpeg,image/bmp,image/png,image/gif,image/jpeg,image/jpg</param></interceptor-ref><interceptor-ref name="defaultStack"></interceptor-ref><interceptor-ref name="defaultStack"></interceptor-ref><result>/success.jsp</result><result name="input">/upload.jsp</result></action>
?其中这个allowedTypes如果不这么些，可能会出错，挺恶心的，
使用了这个拦截器后，就能限制文件上传类型和文件上传大小，但是相应的提示信息是英文的，如果想显示的是中文的出错提示，需要对两个地方进行修改。
就是在messageResource.properties文件中，修改这两个东西的值
struts.messages.error.content.type.not.allowed
struts.messages.error.file.too.large
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其中第一个是文件类型，第二个是上传的文件大小。
如果不是这两个错误，而是发生了其他错误，就修改这个值
struts.message.error.uploading
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做文件上传的时候最好指定这两个属性的值：
struts.multipart.saveDir的值这个是上传临时文件夹，如果不设置，使用的是javax.servlet.context.tempdir的值。也就是work/Catalina/localhost
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struts.multipart.maxSize是上传的表单的请求内容的最大字节
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