《struts2权威指南》学习笔记之struts2文件上传

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：

< html  xmlns ="http://www.w3.org/1999/xhtml" >
< head >
< meta  http-equiv ="Content-Type"  content ="text/html; charset=GBK"   />
< title > 简单的文件上传 </ title >
</ head >
< body >
< form  action ="upload.action"  method ="post"  enctype ="multipart/form-data" >
      文件标题： < input  type ="text"  name ="title"   />< br >
      选择文件： < input  type ="file"  name ="upload"   />< br >
     < input  value ="上传"  type ="submit"   />
</ 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" >
    
< struts >

     < constant  name ="struts.custom.i18n.resources"  value ="globalMessages" />
     < constant  name ="struts.i18n.encoding"  value ="GBK" />

     < package  name ="lee"  extends ="struts-default" >
    
         < action  name ="upload"  class ="lee.UploadAction" >
             < param  name ="savePath" > /upload </ param >
             < result > /succ.jsp </ result >     
         </ 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 >
       < 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 >
       < 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 >
         < title > 上传成功 </ title >
     </ 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" >
    
< struts >

     < constant  name ="struts.custom.i18n.resources"  value ="globalMessages" />
     < constant  name ="struts.i18n.encoding"  value ="GBK" />

     < package  name ="lee"  extends ="struts-default" >
    
         < action  name ="upload"  class ="lee.UploadAction" >
             < param  name ="allowTypes" > image/bmp,image/jpg,image/png,image/gif,image/jpeg </ param >
             < param  name ="savePath" > /upload </ param >
             < result > /succ.jsp </ result >     
             < 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 >

< meta  http-equiv ="Content-Type"  content ="text/html; charset=GBK"   />
< title ></ title >
</ head >
< body >
${requestScope.typeError}
< form  action ="upload.action"  method ="post"  enctype ="multipart/form-data" >
       < input  type ="text"  name ="title"   />< br >
       < input  type ="file"  name ="upload"   />< br >
     < input  value ="upload"  type ="submit"   />
</ form >
</ body >
</ html >