《struts2权威指南》学习笔记之struts2文件上传

来源：互联网发布：魂斗罗水下八关mac 编辑：程序博客网时间：2024/05/02 02:36

struts2没有提供自己的请求解析器，也就是说，struts2不会自己区处理multipart/form-data的请求，它需要调用其他请求解析器，将HTTP请求中的表单域解析出来，但struts2在原有的上传解析器上作了进一步封装，更进一步简化了文件上传

Struts2的struts.properties配置文件中，配置struts2的上传文件解析器

struts.multipart.parser=jakarta (srtuts2默认)，也可以设置为常用的cos,pell等

配置上传页面：

<head>

<title>简单的文件上传</title>

</head>

<body>

文件标题：<input type="text" name="title" /><br>

选择文件：<input type="file" name="upload" /><br>

</form>

</body>

</html>

配置上传action

package lee;

import com.opensymphony.xwork2.Action;

import org.apache.struts2.ServletActionContext;

import java.io.File;

import java.io.*;

import com.opensymphony.xwork2.ActionSupport;

public class UploadAction extends ActionSupport

{

private String title;

private File upload;

private String uploadContentType;

private String uploadFileName;

//接受依赖注入的属性

private String savePath;

//接受依赖注入的方法

public void setSavePath(String value)

{

this.savePath = value;

}

private String getSavePath() throws Exception

{

return ServletActionContext.getRequest().getRealPath(savePath);

}

public void setTitle(String title) {

this.title = title;

}

public void setUpload(File upload) {

this.upload = upload;

}

public void setUploadContentType(String uploadContentType) {

this.uploadContentType = uploadContentType;

}

public void setUploadFileName(String uploadFileName) {

this.uploadFileName = uploadFileName;

}

public String getTitle() {

return (this.title);

}

public File getUpload() {

return (this.upload);

}

public String getUploadContentType() {

return (this.uploadContentType);

}

public String getUploadFileName() {

return (this.uploadFileName);

}

@Override

public String execute() throws Exception

{

System.out.println("开始上传单个文件-----------------------");

System.out.println(getSavePath());

System.out.println("==========" + getUploadFileName());

System.out.println("==========" + getUploadContentType());

System.out.println("==========" + getUpload());

//以服务器的文件保存地址和原文件名建立上传文件输出流

FileOutputStream fos = new FileOutputStream(getSavePath() + "/" + getUploadFileName());

FileInputStream fis = new FileInputStream(getUpload());

byte[] buffer = new byte[1024];

int len = 0;

while ((len = fis.read(buffer)) > 0)

{

fos.write(buffer , 0 , len);

}

return SUCCESS;

}

struts配置文件

<?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">

<param name="savePath">/upload</param>

</action>

</package>

</struts>

web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.5"

xmlns="http://java.sun.com/xml/ns/javaee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee

http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

<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>

<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>

</web-app>

这里web.xml多配置了一个ActionContextCleanUp的配置，这个类是一个filter,他的作用是方便strut2与sitemesh整合，与文件上传本没有关系，但不加载这个filter,可能在上传出出现莫名的异常，加入后就稳定了，可能是strut2的bug吧

文件上传工程页面：

<%@ page language="java" contentType="text/html; charset=GBK"%>

<%@taglib prefix="s" uri="/struts-tags"%>

<html>

<head>

</head>

<body>

上传成功!<br>

文件标题:<s:property value=" + title"/><br>

文件为：<img src="<s:property value="'upload/' + uploadFileName"/>"/><br>

</body>

</html>

运行，选择一个jpg图片，提交，就可以看到上传的页面显示出来了

通常，我们希望限定上传文件的类型，比如说只能上传图片，还需要进一步改造

首先改造Action,增加一个属性和一个方法，属性表示允许上传的文件类型，方法进行验证，是否允许上传

package lee;

import com.opensymphony.xwork2.Action;

import com.opensymphony.xwork2.ActionContext;

import org.apache.struts2.ServletActionContext;

import java.io.*;

import com.opensymphony.xwork2.ActionSupport;

/**

* @author yeeku.H.lee kongyeeku@163.com

* @version 1.0

* <br>Copyright (C), 2005-2008, yeeku.H.Lee

* <br>This program is protected by copyright laws.

* <br>Program Name:

* <br>Date:

public class UploadAction extends ActionSupport

{

private String title;

private File upload;

private String uploadContentType;

private String uploadFileName;

private String allowTypes;

//接受依赖注入的属性

private String savePath;

//接受依赖注入的方法

public void setSavePath(String value)

{

this.savePath = value;

}

private String getSavePath() throws Exception

{

return ServletActionContext.getRequest().getRealPath(savePath);

}

public void setTitle(String title) {

this.title = title;

}

public void setUpload(File upload) {

this.upload = upload;

}

public void setUploadContentType(String uploadContentType) {

this.uploadContentType = uploadContentType;

}

public void setUploadFileName(String uploadFileName) {

this.uploadFileName = uploadFileName;

}

public String getTitle() {

return (this.title);

}

public File getUpload() {

return (this.upload);

}

public String getUploadContentType() {

return (this.uploadContentType);

}

public String getUploadFileName() {

return (this.uploadFileName);

}

@Override

public String execute() throws Exception

{

System.out.println("开始上传单个文件-----------------------");

System.out.println(getSavePath());

System.out.println("==========" + getUploadFileName());

System.out.println("==========" + getUploadContentType());

System.out.println("==========" + getUpload());

//判断是否允许上传

String filterResult=filterType(this.getAllowTypes().split(","));

if(filterResult!=null){

ActionContext.getContext().put("typeError", "您要上传的文件类型不正确");

return filterResult;

}

//以服务器的文件保存地址和原文件名建立上传文件输出流

FileOutputStream fos = new FileOutputStream(getSavePath() + "/" + getUploadFileName());

FileInputStream fis = new FileInputStream(getUpload());

byte[] buffer = new byte[1024];

int len = 0;

while ((len = fis.read(buffer)) > 0)

{

fos.write(buffer , 0 , len);

}

return SUCCESS;

}

public String filterType(String[] types){

String fileType=this.getUploadContentType();

for(String type:types){

if(type.equals(fileType)){

return null;

}

return INPUT;

}

public String getAllowTypes() {

return allowTypes;

}

public void setAllowTypes(String allowTypes) {

this.allowTypes = allowTypes;

}

修改struts.xml定义文件类型及错误返回页面：

<?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">

<param name="allowTypes">image/bmp,image/jpg,image/png,image/gif,image/jpeg</param>

<param name="savePath">/upload</param>

<result name="input">/upload.jsp</result>

</action>

</package>

</struts>

修改上传页面：upload.jsp

<%@ page language="java" contentType="text/html; charset=GBK"%>

<%@taglib prefix="s" uri="/struts-tags"%>

<%@ page isELIgnored="false" %>

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<head>

</head>

<body>

${requestScope.typeError}

</form>

</body>

</html>