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Java以struts2為例介紹如何實(shí)現(xiàn)圖片上傳

更新時(shí)間：2015年11月12日 14:10:34 投稿：mrr

這篇文章主要介紹了Java struts2中如何實(shí)現(xiàn)圖片上傳的相關(guān)資料,需要的朋友可以參考下

總的說(shuō)圖片上傳有兩種方式，一種是把圖片文件寫(xiě)到數(shù)據(jù)庫(kù)中，另一種是存到服務(wù)器文件目錄中。寫(xiě)到數(shù)據(jù)庫(kù)中的圖片文件需要轉(zhuǎn)換成二進(jìn)制流的格式，占用數(shù)據(jù)庫(kù)空間比較，適合少量圖片的存儲(chǔ)，比如說(shuō)，系統(tǒng)中某些小圖標(biāo)，寫(xiě)到數(shù)據(jù)庫(kù)中的優(yōu)點(diǎn)是比較安全，不容易被用戶不小心刪除。

在struts2中實(shí)現(xiàn)(以圖片上傳為例)

1.FileUpload.jsp代碼清單如下:

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>The FileUplaodDemo In Struts2</title>
</head>
<body>
<s:form action="fileUpload" method="post" enctype="multipart/form-data" namespace="/">
<s:file name="myFile" label="MyFile" ></s:file>
<s:textfield name="caption" label="Caption"></s:textfield>
<s:submit label="提交"></s:submit>
</s:form>
</body>
</html>

2.ShowUpload.jsp的功能清單如下:

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>ShowUpload</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>

3.FileUploadAction.java的代碼清單如下 :

package com.chris;
import java.io.*;
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 ;
//注意，文件上傳時(shí)<s:file/>同時(shí)與myFile，myFileContentType,myFileFileName綁定
//所以同時(shí)要提供myFileContentType,myFileFileName的set方法
private File myFile; //上傳文件
private String contentType;//上傳文件類型
private String fileName; //上傳文件名
private String imageFileName;
private String caption;//文件說(shuō)明，與頁(yè)面屬性綁定
public void setMyFileContentType(String contentType) {
System.out.println("文件類型 : " + contentType);
this .contentType = contentType;
}
public void setMyFileFileName(String fileName) {
System.out.println("文件名稱 : " + 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;
}
}

注:此時(shí)僅為方便實(shí)現(xiàn)Action所以繼承ActionSupport,并Overrider execute()方法

在struts2中任何一個(gè)POJO都可以作為Action

4.struts.xml清單如下:

<?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="example" namespace="/" extends="struts-default">
<action name="fileUpload" class="com.chris.FileUploadAction">
<interceptor-ref name="fileUploadStack"/>
<result>/ShowUpload.jsp</result>
</action>
</package>
</struts>

5.web.xml清單如下:

<?xml version="1.0" encoding="UTF-8"?>
<web-app 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">
<filter >
<filter-name > struts-cleanup </filter-name >
 <filter-class >
org.apache.struts2.dispatcher.ActionContextCleanUp
</filter-class >
 </filter >
 <filter-mapping >
<filter-name > struts-cleanup </filter-name >
 <url-pattern > /* </url-pattern >
 </filter-mapping >
 <filter>
 <filter-name>struts2</filter-name>
 <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
 </filter>
 <filter-mapping>
<filter-name>struts2</filter-name>
 <url-pattern>/*</url-pattern>
 </filter-mapping>
 <welcome-file-list>
 <welcome-file>Index.jsp</welcome-file>
 </welcome-file-list>
</web-app>

以上內(nèi)容是小編給大家介紹的Java struts2中如何實(shí)現(xiàn)圖片上傳的全部?jī)?nèi)容，希望大家喜歡。

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