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struts2中实现文件上传功能
在web项目中,文件上传、头像上传这样的功能经常是要用到的,下面就以在struts2中实现文件上传功能为例子,简单地理一下文件上传功能的编码思路。
项目目录结构
项目源代码
web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <filter> <filter-name>struts 2</filter-name> <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class> </filter> <filter-mapping> <filter-name>struts 2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
struts.xml
<span style="font-size:12px;"><?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"> <action name="upload" class="com.upload.action.UploadAction" method="upload"> <result name="success">/success.jsp</result> <result name="error">/upload.jsp</result> </action> </package> </struts></span>
UploadAction.java
package com.upload.action; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.util.UUID; import javax.servlet.ServletContext; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.ActionContext; import com.opensymphony.xwork2.ActionSupport; public class UploadAction extends ActionSupport{ private File upload; //上传文件 private String uploadFileName; //上传的文件名 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 upload() throws Exception{ //如果选择了上传功能,则执行上传操作;否则,不作任何操作 if(getUpload() != null){ //根据上传的文件得到输入流 InputStream is = new FileInputStream(getUpload()); //更改上传文件名为:随机数+上传文件名 setUploadFileName(UUID.randomUUID().toString()+ getUploadFileName()); //指定输出流地址,此处是输出到服务器项目的根目录下的images/userPhoto下 OutputStream os = new FileOutputStream(getWebRootPath() + "images\\userPhoto\\" + getUploadFileName()); byte buffer[] = new byte[1024]; int count = 0; //把文件写到指定位置的文件中 while((count = is.read(buffer)) > 0){ os.write(buffer, 0, count); } //关闭输出流对象 os.close(); //关闭输入流对象 is.close(); //返回 return SUCCESS; } else { return ERROR; } } /** * 获得web项目根目录 */ public String getWebRootPath() throws Exception { ActionContext actionContext = ActionContext.getContext(); ServletContext servletContext = (ServletContext)actionContext.get(ServletActionContext.SERVLET_CONTEXT); String rootPath = servletContext.getRealPath("/"); return rootPath; } }<strong> </strong>
upload.jsp
<span style="font-size:12px;"><%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <%@ taglib uri="/struts-tags" prefix="s" %> <% 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=http://www.mamicode.com/""> >
success.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>上传成功</title> </head> <body> 恭喜您,文件上传成功!点<a href=http://www.mamicode.com/"upload.jsp">这里回去>
上面的方法不仅可用于上传图片类型,也适用于其他文件类型的上传。
注意: Struts 2上传文件的默认大小限制是2MB,所以在测试的时候文件不能太大,最好找个小的文件。 如果要修改默认大小,只需要在Struts 2的struts.properties或struts.xml中修改struts.multipart.maxSize的值,如struts.multipart.maxSize=1024表示上传文件的总大小不能超过1KB 。
如在struts.xml中设置上传的文件大小不超过50MB,可以在struts.xml的<struts> </struts>标签里面添加:
<constant name="struts.multipart.maxSize" value=http://www.mamicode.com/"51200"/>
struts2中实现文件上传功能
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