Struts2.0上传练习-优快云博客

本文记录了一次使用Struts 2框架实现文件上传的过程，包括遇到的问题及解决方法。涉及Struts 2配置、文件上传Action编写、前端表单设计等内容。

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终于上次的项目告一段落了，可以重新学习Struts了，于是终于吃过饭就开始捣鼓了，因为早就从网上把MAX先生的教程下来了，就看了看教程，着手进行吧

代码都是Max先生的，但是中间却出现了不少的错误，

主要文件有：FileUpload.jsp上传页面

xml 代码

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
>
<html xmlns ="http://www.w3.org/1999/xhtml">
<head>
<title> Struts 2 File Upload title>
head >
<body >
<s:form action ="fileUpload" method ="POST" enctype ="multipart/form-data" >
<s:file name ="myFile" label ="Image File"/>
<s:textfield name ="caption" label ="Caption"/>
<s:submit/>
s:form >
body >
html >

action处理页面FileUploadAction.java

java 代码

package tutorial;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Date;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class FileUploadAction extends ActionSupport {
private static final long serialVersionUID = 572146812454l;
private static final int BUFFER_SIZE = 16 * 1024;
private File myFile;
private String contentType;
private String fileName;
private String imageFileName;
private String caption;
public void setMyFileContentType(String contentType) {
this.contentType = contentType;
}
public void setMyFileFileName(String fileName) {
this.fileName = fileName;
}
public void setMyFile(File myFile) {
this.myFile = myFile;
}
public String getImageFileName() {
return imageFileName;
}
public String getCaption() {
return caption;
}
public void setCaption(String caption) {
this.caption = caption;
}
private static void copy(File src, File dst) {
try {
InputStream in = null;
OutputStream out = null;
try {
in = new BufferedInputStream(new FileInputStream(src),
BUFFER_SIZE);
out = new BufferedOutputStream(new FileOutputStream(dst),
BUFFER_SIZE);
byte[] buffer = new byte[BUFFER_SIZE];
while (in.read(buffer) > 0) {
out.write(buffer);
}
} finally {
if (null != in) {
in.close();
}
if (null != out) {
out.close();
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
private static String getExtention(String fileName) {
int pos = fileName.lastIndexOf(".");
return fileName.substring(pos);
}
@Override
public String execute() {
imageFileName = new Date().getTime() + getExtention(fileName);
File imageFile = new File(ServletActionContext.getServletContext()
.getRealPath("/UploadImages")
+ "/" + imageFileName);
copy(myFile, imageFile);
return SUCCESS;
}
}

ShowUpload.jsp上传成功显示页面

xml 代码

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" >
<html xmlns ="http://www.w3.org/1999/xhtml" >
<head>
<title> Struts 2 File Upload </title >
</head>
<body>
<div style="padding: 3px; border: solid 1px #cccccc; text-align: center" >
<img src='UploadImages/<s:property value ="imageFileName" />'/>
<br/>
<s:property value ="caption"/>
</div>
</body>
</html>

struts.xml配置文件

xml 代码

<?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 ="fileUploadDemo" extends ="struts-default" >
<action name ="fileUpload" class ="tutorial.FileUploadAction" >
<interceptor-ref name ="fileUploadStack" />
<result name ="success" >/ShowUpload.jsp</result >
</action>
</package >
</struts >

web.xml

xml 代码

<?xml version="1.0" encoding="UTF-8" ?>
<web-app id ="WebApp_9" version ="2.4"
xmlns ="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation ="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" >
<display-name > Struts 2 Fileupload </display-name >
<filter >
<filter-name > struts-cleanup </filter-name >
<filter-class >
org.apache.struts2.dispatcher.ActionContextCleanUp
</filter-class >
</filter >
<filter >
<filter-name > struts2 </filter-name >
<filter-class >
org.apache.struts2.dispatcher.FilterDispatcher
</filter-class >
</filter >
<filter-mapping >
<filter-name > struts-cleanup </filter-name >
<url-pattern > /* </url-pattern >
</filter-mapping >
<filter-mapping >
<filter-name > struts2 </filter-name >
<url-pattern > /* </url-pattern >
</filter-mapping >
<welcome-file-list >
<welcome-file > index.html </welcome-file >
</welcome-file-list >
</web-app >

在进行调试的时候发现我的运气是相当的好啊，因为别人提出的错误我都遇到了，比如如下：

java 代码

Servlet.service() for servlet SimpleUploader threw exception
java.lang.RuntimeException: Unable to load bean org.apache.struts2.dispatcher.multipart.MultiPartRequest (jakarta) - [unknown location]

我在网上搜了下，发现有人这样解决的：

xml 代码

只要不让struts2拦截处理上传事件，就应该没问题了。
修改web.xml，把原来的
<filter-mapping>
<filter-name>struts</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
改为
<filter-mapping>
<filter-name>struts</filter-name>
<url-pattern>*.action</url-pattern>
</filter-mapping>
而上传页面调用时直接用文件名调用（如upload.jsp）。struts2只处理 *.action 的请求。

但是我用了一下出现了更麻烦的错误，于是又找了下是因为我的包所用版本太低的原因于是到Apache上下载了最新的包删除旧的导入新的刷新，打开tomcat服务,输入地址，又出现了一个错误

java 代码

javax.servlet.ServletException: String index out of range: -1
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:518)
org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:421)
org.apache.struts2.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:99)

因为我的代码是从max先生的文章直接复制粘贴的，开始有很多多余的空格，我就一个个删除的，这时我想是不是空格的问题，于是又检查一遍代码，把空格全部删除，ok..

看来代码是要自己敲的，还是有好处的。】

这里记下，提醒自己，呵呵

高手就不用看了，因为我们是菜鸟，呵呵