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Struts2系列之文件上传下载

2017-07-10 08:44 337 查看

文件上传的必要条件

1. 表单的method 必须是post

2. 表单提供enctype必须是mulipart/from-data

3.提供input type=”file”类型上传输入域

注意:如果是大文件浏览器也会拦截不让上传

在struts2中文件上传是由fileUpload拦截器完成的

单文件上传:

jsp:

<head>
<title>单文件上传</title>
</head>
<body>
<%--文件上传必要的条件--%>
<%--1, 要有一个表单 方式要是post请求--%>
<%--2, enctype="multipart/form-data--%>
<%--3, <input type="file" name="photo">--%>
<s:fielderror/>
<s:actionerror/>
<form action="${pageContext.request.contextPath}/upload.action" method="post" enctype="multipart/form-data">

姓名:<input type="text" name="username">
头像:<input type="file" name="photo">
<input type="submit" value="上传">

</form>


action: 

public class SingleUploadAction extends ActionSupport {

private String username;
private File photo;//必须是file类型,名字对应着表单的上传输入域
private String photoFileName;//固定的写法:XXXFileName
private String photoContentType;//上传文件的MIME类型,固定写法

public  String upload() throws IOException {
System.out.println(username + "fkdsjf");
System.out.println(photoContentType);
ServletContext servletContext = ServletActionContext.getServletContext();
//获得存放文件的真是目录
String directory = servletContext.getRealPath("/file");
//构建目标文件
File target = new File(directory,photoFileName);
//写入目标文件
FileUtils.copyFile(photo, target);
return SUCCESS;
}

public String getUsername() {
return username;
}

public void setUse
d7a3
rname(String username) {
this.username = username;
}

public File getPhoto() {
return photo;
}

public void setPhoto(File photo) {
this.photo = photo;
}

public String getPhotoFileName() {
return photoFileName;
}

public void setPhotoFileName(String photoFileName) {
this.photoFileName = photoFileName;
}

public String getPhotoContentType() {
return photoContentType;
}

public void setPhotoContentType(String photoContentType) {
this.photoContentType = photoContentType;
}

}


struts.xml

<!--修改文件的大小 (10M 1024*1024*10)-->
<constant name="struts.multipart.maxSize" value="10485760"/>
<!--由于我们在不被允许的格式中要显示用户可以看得懂的文字 可以写一个配置文件 constant name="国际化的一种方式"-->
<constant name="struts.custom.i18n.resources" value="fileUploadMessage"/>

<package name="p1" extends="struts-default">
<action name="upload" class="com.wangyjie.struts.fileupload.SingleUploadAction" method="upload">
<!--因为在默认的拦截器中  直接引用就可以了-->
<interceptor-ref name="defaultStack">
<!--限制文件后缀-->
<param name="fileUpload.allowedExtensions">.jsp, png</param>
</interceptor-ref>

<result name="success">/success.jsp</result>
<result name="input">/singleFileUpload.jsp</result>
</action>
</package>


文件下载

结果集类型的使用 stream

• 动作类的书写规范 : inputStream / fileName

•struts.xml中action result的type=“stream”两个参数:

◦ inputName[输入流的属性名]

◦ contentDisposition=attachment;filename=${fileName}[通知浏览器以下载形式打开]

action: 

package com.wangyjie.struts.down;

import com.opensymphony.xwork2.ActionSupport;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.FilenameUtils;
import org.apache.struts2.ServletActionContext;
import sun.misc.BASE64Encoder;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URLEncoder;

/**
* Created by dllo on 17/7/7.
*/
public class downLoadAction extends ActionSupport {

//定义一个输入流
private InputStream inputStream;
private String imageFileName;

public String getImageFileName() {

return imageFileName;
}

public void setImageFileName(String imageFileName) {
this.imageFileName = imageFileName;
}

public InputStream getInputStream() {
return inputStream;
}

public void setInputStream(InputStream inputStream) {
this.inputStream = inputStream;
}

public String download() throws IOException {

//实现下载.给inputStream赋值
String realPath = ServletActionContext.getServletContext().getRealPath("/杰哥.jpg");
//获取文件名
//        imageFileName = FilenameUtils.getName(realPath);
imageFileName = filenameEncoding(FilenameUtils.getName(realPath), ServletActionContext.getRequest(),ServletActionContext.getResponse());
inputStream = new FileInputStream(realPath);
//        FileUtils.getFile(realPath).getName();
return SUCCESS;
}

//中文处理
public String filenameEncoding(String filename, HttpServletRequest request, HttpServletResponse response) throws IOException {
String agent = request.getHeader("User-Agent"); //获取浏览器的类型    System.out.println(agent);
if (agent.contains("Firefox")) {
BASE64Encoder base64Encoder = new BASE64Encoder();
filename = "=?utf-8?B?"                + base64Encoder.encode(filename.getBytes("utf-8"))
+ "?=";
} else if(agent.contains("MSIE")) {
filename = URLEncoder.encode(filename, "utf-8");
} else if (agent.contains("Safari")){
filename = new String(filename.getBytes("UTF-8"),"ISO8859-1");
}else {
filename = URLEncoder.encode(filename, "utf-8");
}
return filename;
}

}


struts.xml

<package name="downLoad" extends="struts-default">
<action name="download" class="com.wangyjie.struts.down.downLoadAction" method="download">
<result name="success" type="stream">
<!--指定动作类中的输入流,属性名-->
<param name="inputName">inputStream</param>
<!--通知浏览器以下载的形式打开-->
<!--文件名动态处理 添加 fileName 属性-->
<param name="contentDisposition">attachment;filename=${imageFileName}</param>
</result>
</action>
</package>
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