一、简述
struts2的文件上传其实也是通过拦截器来实现的，只是该拦截器定义为默认拦截器了，所以不用自己去手工配置，<interceptor name="fileupload" class="org.apache.struts2.interceptor.fileuploadinterceptor"/>
二、指定用户上传文件的大小，有两种方式
1）默认是在default.properties 文件的 struts.multipart.maxsize=2097152 键值指定为2097152 也就是2m，通过计算 2097152/(1024*1024) = 2 m
那我们可以改变其默认值，只要在src目录下，新建一个 struts.properties 文件，指定上传大小 如下：
一次上传只可以上传10m，不管一次上传多少个文件，按总和计算
2）在struts.xml文件中指定，如图：
其实name就对应struts.properties的键，value对应 值
注意：如果即在struts.properties设定文件上传大小，又在struts.xml 设定文件上传大小，则struts.properties的优先级高于struts.xml，一般在一处指定上传大小即可，推荐 struts.properties
三、struts2之单文件上传
1.fileupload.jsp
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<%@ page language="java" import="java.util.*" pageencoding="utf-8"%>
<%
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="<%=basepath%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
<title>my jsp 'fileupload.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" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
-->
</head>
<body>
<!-- enctype 默认是 application/x-www-form-urlencoded -->
<form action="fileupload2" enctype="multipart/form-data" method="post" >
用户名：<input type="text" name="usename"> <br/>
上传文件：<input type="file" name="file1"><br/>
<input type="submit" value="提交"/>
</form>
</body>
</html>
2.具体处理上传的 fileupload.java
package com.struts2.fileupload;
import java.io.file;
import java.io.fileinputstream;
import java.io.fileoutputstream;
import java.io.inputstream;
import java.io.outputstream;
import org.apache.struts2.servletactioncontext;
import com.opensymphony.xwork2.actionsupport;
/**
* 单个文件上传
* @author administrator
* 上传文件其实是上传了两份，
*
* 首先将上传的文件保存到 default.properties 文件中 struts.multipart.savedir键指定的目录中
* 默认是空的
* 保存在 tomcat 6.0\work\catalina\localhost\struts2目录下以.tmp后缀名的文件
*
* 如果要在 struts.multipart.savedir 指定目录， 则可以在 src文件夹下 建一个 struts.properties,
* 覆盖 default.properties 的某些键值
*
* 还有一份是 存放在自己设定的目录下
*/
public class fileupload extends actionsupport {
private string usename ;
private file file1 ; //具体上传文件的 引用 , 指向临时目录中的临时文件
private string file1filename ; // 上传文件的名字 ,filename 固定的写法
private string file1contenttype ; //上传文件的类型， contenttype 固定的写法
public string getusename() {
return usename;
}
public void setusename(string usename) {
this.usename = usename;
}
public file getfile1() {
return file1;
}
public void setfile1(file file1) {
this.file1 = file1;
}
public string getfile1filename() {
return file1filename;
}
public void setfile1filename(string file1filename) {
this.file1filename = file1filename;
}
public string getfile1contenttype() {
return file1contenttype;
}
public void setfile1contenttype(string file1contenttype) {
this.file1contenttype = file1contenttype;
}
@override
public string execute() throws exception {
//获取文件存储路径
string path = servletactioncontext.getrequest().getrealpath("/upload");
//输出流
outputstream os = new fileoutputstream(new file(path,file1filename));
//输入流
inputstream is = new fileinputstream(file1);
byte[] buf = new byte[1024];
int length = 0 ;
while(-1 != (length = is.read(buf) ) )
{
os.write(buf, 0, length) ;
}
is.close();
os.close();
return success;
}
}
3.最终显示结果的页面，filedemo.jsp
<%@ page language="java" import="java.util.*" pageencoding="utf-8"%> <%@ taglib prefix="s" uri="/struts-tags" %> <% 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="<%=basepath%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" > <title>my jsp 'filedemo.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" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" > --> </head> <body> 上传成功: <br/> usename: <s:property value="usename" /><br/> file: <s:property value="file1filename"/><br/> contenttype: <s:property value="file1contenttype"/> </body> </html>
四、struts2之多文件上传
1.fileupload.jsp
<%@ page language="java" import="java.util.*" pageencoding="utf-8"%>
<%
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="<%=basepath%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
<title>my jsp 'fileupload.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" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
-->
</head>
<body>
<!-- enctype 默认是 application/x-www-form-urlencoded -->
<form action="fileupload2" enctype="multipart/form-data" method="post" >
用户名：<input type="text" name="usename"> <br/>
上传文件：<input type="file" name="file1"><br/>
上传文件： <input type="file" name="file1"><br/> <!-- 两个名字相同 都是file1 -->
<input type="submit" value="提交"/>
</form>
</body>
</html>
两个上传文件的name属性值要是一样的，后台方便处理
2.具体处理上传文件的fileupload2.java
多文件上传用集合的方式
package com.struts2.fileupload;
import java.io.file;
import java.io.fileinputstream;
import java.io.fileoutputstream;
import java.io.inputstream;
import java.io.outputstream;
import java.util.list;
import org.apache.struts2.servletactioncontext;
import com.opensymphony.xwork2.actionsupport;
/**
* 多文件上传，用集合的方式
* @author administrator
*
*/
public class fileupload2 extends actionsupport {
private string usename ;
private list<file> file1 ;
private list<string> file1filename ;
private list<string> file1contenttype ;
public string getusename() {
return usename;
}
public void setusename(string usename) {
this.usename = usename;
}
public list<file> getfile1() {
return file1;
}
public void setfile1(list<file> file1) {
this.file1 = file1;
}
public list<string> getfile1filename() {
return file1filename;
}
public void setfile1filename(list<string> file1filename) {
this.file1filename = file1filename;
}
public list<string> getfile1contenttype() {
return file1contenttype;
}
public void setfile1contenttype(list<string> file1contenttype) {
this.file1contenttype = file1contenttype;
}
@override
public string execute() throws exception {
//获取文件存储路径
string path = servletactioncontext.getrequest().getrealpath("/upload");
for(int i = 0 ; i < file1.size() ; i++ )
{
outputstream os = new fileoutputstream(new file(path,file1filename.get(i)));
inputstream is = new fileinputstream(file1.get(i));
byte[] buf = new byte[1024];
int length = 0 ;
while(-1 != (length = is.read(buf) ) )
{
os.write(buf, 0, length) ;
}
is.close();
os.close();
}
return success;
}
}
3.用于显示的界面filedemo.jsp
<%@ page language="java" import="java.util.*" pageencoding="utf-8"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<%
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="<%=basepath%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
<title>my jsp 'filedemo2.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" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
-->
</head>
<body>
上传成功：<br/>
usename:<s:property value="usename"/><br/>
<!-- 遍历值 -->
<s:iterator value="file1filename" id="f"> <!-- id是一个对象，目前是一个字符串集合 可任意命名 -->
文件:<s:property value="#f"/> <br/>
<!-- 这里也可以调用方法 <s:property value="#f.touppercase()"/> -->
</s:iterator>
</body>
</html>
遍历集合的方式，用struts2提供的标签 iterator 可以实现
<s:iterator value="file1filename" id="f"> <!-- id是一个对象，目前是一个字符串集合 可任意命名-->
文件:<s:property value="#f"/> <br/>
<!-- 这里也可以调用方法 <s:property value="#f.touppercase()"/> -->
touppercase()字符串的方法是把字母转为大写
</s:iterator>
下载链接：
1）servlet 文件上传 点击打开
2）struts2之下载 点击打开
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