（十）struts2之文件上傳

自接觸這麼多種技術的上傳來看，還是Struts2的上傳最好用，雖然之前有篇文章已經總結了幾乎我接觸到的所有類型的上傳，但Struts2方面感覺講的還是不夠細緻。

本文就單文件上傳和批量文件上傳來進行講解

具體示例

首頁上傳頁面

Html代碼

<span style="font-size: large;"><span style="font-size: large;"><%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Struts2文件上傳示例</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>
<h3>Struts2文件上傳示例</h3><hr/>
<form action="fileUpload.action" method="post" enctype="multipart/form-data">
<input type="file" name="up" style="width: 500px"/> <s:fielderror name="up"></s:fielderror><br/>
<input type="submit" value="開始上傳"/>
<s:token/>
</form>
<h3>Struts2批量文件上傳示例</h3><hr/>
<form action="batchFileUpload.action" method="post" enctype="multipart/form-data">
<s:fielderror name="up"></s:fielderror><br/>
<input type="file" name="up" style="width: 500px"/> <br/>
<input type="file" name="up" style="width: 500px"/><br/>
<input type="file" name="up" style="width: 500px"/> <br/>
<input type="submit" value="開始上傳"/>
<s:token/>
</form>
</body>
</html></span></span>

單文件上傳的Action

Java代碼

<span style="font-size: large;"><span style="font-size: large;">package com.javacrazyer.action;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class FileUploadAction extends ActionSupport {
private static final long serialVersionUID = -7001482935770262132L;
private File up;
private String upContentType;
private String upFileName;
private String destPath;
public String execute() throws Exception{
System.out.println("contentType==" + this.upContentType);
System.out.println("fileName==" + this.upFileName);
File basePath = new File(ServletActionContext.getServletContext().getRealPath(destPath));
if(!basePath.exists()){
basePath.mkdirs();
}
copy(up, new File(basePath.getCanonicalPath()+"/" + upFileName));
return SUCCESS;
}
public void copy(File srcFile, File destFile) throws IOException{
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
try{
bis = new BufferedInputStream(new FileInputStream(srcFile));
bos = new BufferedOutputStream(new FileOutputStream(destFile));
byte[] buf = new byte[8192];
for(int count = -1; (count = bis.read(buf))!= -1; ){
bos.write(buf, 0, count);
}
bos.flush();
}catch(IOException ie){
throw ie;
}finally{
if(bis != null){
bis.close();
}
if(bos != null){
bos.close();
}
}
}
public File getUp() {
return up;
}
public void setUp(File up) {
this.up = up;
}
public String getUpContentType() {
return upContentType;
}
public void setUpContentType(String upContentType) {
this.upContentType = upContentType;
}
public String getUpFileName() {
return upFileName;
}
public void setUpFileName(String upFileName) {
this.upFileName = upFileName;
}
public String getDestPath() {
return destPath;
}
public void setDestPath(String destPath) {
this.destPath = destPath;
}
}</span></span>

多文件上傳的Action

Java代碼

<span style="font-size: large;"><span style="font-size: large;">package com.javacrazyer.action;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
/**
* 批量文件上傳
*
* 這裏有一點非常重要：就是凡是頁面上的file文本域的name=xxx的，
* 那麼Action的三個屬性必須爲xxx,xxxContentType,xxxFileName
*
*
*/
public class BatchFileUploadAction extends ActionSupport {
private static final long serialVersionUID = -7001482935770262132L;
private List<File> up;
private List<String> upContentType;
private List<String> upFileName;
private String destPath;
public String execute() throws Exception{
//System.out.println("contentType==" + this.upContentType);
//System.out.println("fileName==" + this.upFileName);
File basePath = new File(ServletActionContext.getServletContext().getRealPath(destPath));
if(!basePath.exists()){
basePath.mkdirs();
}
int size = up == null ? 0 : up.size();
for(int i = 0; i < size; i++){
/*
* 如果需要限制上傳文件的類型，那麼可以解開此註釋
* if(isAllowType(upContentType.get(i))){
copy(up.get(i), new File(basePath.getCanonicalPath()+"/" + upFileName.get(i)));
}else{
upFileName.remove(i);
}*/
copy(up.get(i), new File(basePath.getCanonicalPath()+"/" + upFileName.get(i)));
}
return SUCCESS;
}
public void copy(File srcFile, File destFile) throws IOException{
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
try{
bis = new BufferedInputStream(new FileInputStream(srcFile));
bos = new BufferedOutputStream(new FileOutputStream(destFile));
byte[] buf = new byte[8192];
for(int count = -1; (count = bis.read(buf))!= -1; ){
bos.write(buf, 0, count);
}
bos.flush();
}catch(IOException ie){
throw ie;
}finally{
if(bis != null){
bis.close();
}
if(bos != null){
bos.close();
}
}
}
public List<File> getUp() {
return up;
}
public void setUp(List<File> up) {
this.up = up;
}
public List<String> getUpContentType() {
return upContentType;
}
public void setUpContentType(List<String> upContentType) {
this.upContentType = upContentType;
}
public List<String> getUpFileName() {
return upFileName;
}
public void setUpFileName(List<String> upFileName) {
this.upFileName = upFileName;
}
public String getDestPath() {
return destPath;
}
public void setDestPath(String destPath) {
this.destPath = destPath;
}
public static boolean isAllowType(String type){
List<String> types = new ArrayList<String>();
types.add("image/pjpeg");
types.add("text/plain");
types.add("image/gif");
types.add("image/x-png");
if(types.contains(type)){
return true;
}else{
return false;
}
}
}</span></span>

針對上面兩個Action,都得有那麼三個屬性【上傳的文件，文件類型，文件名】，並且開頭必須與表單file的name值一樣

在Action中添加一個List<File>類型的與頁面所有file域同名的屬性。private List<File> up;

添加一個以file域名開頭，後面跟ContentType的字符串列表屬性，這個由Struts2的文件上傳攔截器賦文件類型值。如：private List<String> upContentTyp;

添加一個以file域名開頭，後面跟FileName的字符串列表屬性，這個由Struts2的文件上傳攔截器賦文件名的值。如：private List<String> upFileName;

通過IO流循環操作，完成文件的讀寫。

記住：在struts2的Action中，對於無論是單個文件上傳還是批量上傳，就是凡是頁面上的file文本域的name=xxx的，那麼Action的三個屬性必須爲xxx,xxxContentType,xxxFileName

存放上傳類型錯誤信息的資源文件

msg_zh_CN.properties

Xml代碼

<span style="font-size: large;"><span style="font-size: large;">struts.messages.error.content.type.not.allowed=\u4E0A\u4F20\u7684\u6587\u4EF6\u7C7B\u578B\u662F\u975E\u6CD5\u7684
#struts.messages.error.uploading=文件不能上傳的通用錯誤信息
#struts.messages.error.file.too.large=上傳文件長度過大的錯誤信息
#struts.messages.error.content.type.not.allowed= 當上傳文件不符合指定的contentType</span></span>

msg_en_US.properties

Html代碼

<span style="font-size: large;"><span style="font-size: large;">struts.messages.error.content.type.not.allowed=upload file contenttype is invalidate</span></span>

src/struts.xml

Xml代碼

<span style="font-size: large;"><span style="font-size: large;"><?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.1.7//EN"
"http://struts.apache.org/dtds/struts-2.1.7.dtd">
<struts>
<constant name="struts.i18n.encoding" value="UTF-8"/>
<constant name="struts.action.extension" value="action,do,go,xkk"/>
<constant name="struts.configuration.xml.reload" value="true"/>
<constant name="struts.devMode" value="false"/>
<constant name="struts.serve.static.browserCache" value="false" />
<constant name="struts.ognl.allowStaticMethodAccess" value="true"/>
<!-- 指定由spring負責action對象的創建
<constant name="struts.objectFactory" value="spring" />-->
<constant name="struts.enable.DynamicMethodInvocation" value="false"/>
<constant name="struts.multipart.maxSize" value="102400000000000" />
<constant name="struts.custom.i18n.resources" value="msg"/>
<package name="my" extends="struts-default" namespace="/">
<interceptors>
<interceptor-stack name="myStack">
<interceptor-ref name="defaultStack"/>
<interceptor-ref name="token"/>
</interceptor-stack>
</interceptors>
<default-interceptor-ref name="myStack"/>
<global-results>
<result name="invalid.token">/error.jsp</result>
</global-results>
<action name="fileUpload" class="com.javacrazyer.action.FileUploadAction">
<param name="destPath">/abc</param>
<result name="input">/index.jsp</result>
<result>/success.jsp</result>
</action>
<action name="batchFileUpload" class="com.javacrazyer.action.BatchFileUploadAction">
<param name="destPath">/abc</param>
<result name="input">/index.jsp</result>
<result>/success.jsp</result>
</action>
</package>
</struts></span></span>

token防止重複提交表單【主要是防止上傳過後點擊瀏覽器的後退按鈕，再次提交這個問題】

1) 在頁面的表單中添加<s:token/>

2) 在要使用token的Action配置中添加token或tokenSession攔截器。

看到沒有，我們在配置中還配置了<result name="input">/index.jsp</result>，這樣的話，如果上傳失敗就會跳到index.jsp頁面，不過現在

我們還沒涉到類型限制的問題，接下來，將的就是如何爲上傳添加文件類型

struts2中爲文件上傳添加類型限制有兩種方式：

第一種方式在Action純寫代碼方式

看BatchFileUploadAction中，copy(up.get(i), new File(basePath.getCanonicalPath()+"/" + upFileName.get(i)));這句話，如果將其上邊的被註釋的段落註釋去掉，將本行註釋掉，那麼就可以起到文件限制，具體可以在isAllowType這個方法中配置

第二種方式在struts.xml中配置

將上邊struts.xml中的

Java代碼