Struts中上传文件需要注意的地方
今天突然想研究下Struts的上传功能，没想到搞了两个小时才搞出来，卡在一个地方，总是报错说参数类型转化异常，结果我改动了下页面，却又神出鬼没的上传成功了，赶紧记录下
首先是web.xml中的配置，我个人喜欢每次弄个字符过滤器，以免出错
<filter>
<filter-name>filter</filter-name>
<filter-class>com.wujintao.dao.SetCharacterEncodingFilter</filter-class>
<init-param>
<param-name>encode</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<init-param>
<param-name>debug</param-name>
<param-value>2</param-value>
</init-param>
<init-param>
<param-name>detail</param-name>
<param-value>2</param-value>
</init-param>
<load-on-startup>2</load-on-startup>
</servlet>
<!-- Standard Action Servlet Mapping -->
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
struts-config.xml中的配置，挺奇怪的最后两行必须得配上
<struts-config>
<!-- ================================================ Form Bean Definitions -->
<form-beans>
<form-bean name="uploadForm" type="com.javacrazyer.web.formbean.UploadForm"/>
</form-beans>
<!-- =========================================== Action Mapping Definitions -->
<action-mappings>
<action path="/upload"
name="uploadForm"
type="com.javacrazyer.web.action.UploadAction">
<forward name="succ" path="/succ.jsp"/>
<forward name="fail" path="/failure.jsp"/>
</action>
</action-mappings>
<controller bufferSize="8192" maxFileSize="1M" />
<message-resources parameter="msgs"/>
</struts-config>
其次就是业务逻辑的代码了，在这之前我必须说下，这个Struts的上传用到的关键点就是自己自带的FormFile类了，因此在FormBean里面应该配上一个FormFile类型的属性
private String description; //文件的描述
private FormFile file; //文件具体内容对应的实例
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public FormFile getFile() {
return file;
}
public void setFile(FormFile file) {
this.file = file;
}
业务逻辑处理代码
//具体业务流程处理方法，由Struts框架回调
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
String toURL = "succ";
//取数据
UploadForm uForm = (UploadForm)form;
String desc = uForm.getDescription();
System.out.println("description==" + desc);
FormFile ff = uForm.getFile();
if(ff == null){
toURL = "fail";
return mapping.findForward(toURL);
}
System.out.println("文件名：" + ff.getFileName());
System.out.println("内容类型：" + ff.getContentType());
System.out.println("文件大小：" + ff.getFileSize() + "字节");
BufferedInputStream bis = new BufferedInputStream(ff.getInputStream());
//目标路径
String destPath = this.getServlet().getServletContext().getRealPath("/files");
System.out.println(destPath+"===============================");
BufferedOutputStream bos = null;
try{
bos = new BufferedOutputStream(new FileOutputStream(destPath + "/" + ff.getFileName()));
//从源文件中取数据，写到目标文件中
byte [] buff = new byte[8192];
for(int len = -1; (len = bis.read(buff)) != -1;){
bos.write(buff, 0, len);
}
bos.flush();
}catch(IOException ie){
ie.printStackTrace();
toURL = "fail";
}finally{
if(bis != null){
try{
bis.close();
}catch(IOException ie){
ie.printStackTrace();
}
}
if(bos != null){
try{
bos.close();
}catch(IOException ie){
ie.printStackTrace();
}
}
}
return mapping.findForward(toURL);
}
接下来我要说的，大家都猜到了肯定是JSP页面的上传表单了，这里就是卡住我的罪魁祸首
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<html:form action="upload.do" enctype="multipart/form-data">
<html:text property="description"></html:text>
<html:file property="file"/>
<html:submit/>
</html:form>
</body>
</html>
为什么说它是罪魁祸首呢，因为一直都认为<input type="file" />是最佳的上传表单，谁知道我找了大半天，竟然出现在这里的它必须是STRUTS标签的表单元素，郁闷！！！深刻的教训啊。