Use struts2 + jsp to upload files. Use struts2 to upload files.

Use struts2 + jsp to upload files. Use struts2 to upload files.

This document describes how to upload files using struts2 + jsp. Share it with you for your reference. The details are as follows:

1. java code:

Package com. wang. test; import java. io. inputStream; import org. apache. struts2.ServletActionContext; import com. opensymphony. xwork2.Action; import com. opensymphony. xwork2.ActionSupport; The public class DownLoadPhoneFile extends ActionSupport {// The getDownloadFile () method must return InputStream. The getResourceAsStream () method outputs the resource public InputStream getDownloadFile () {return ServletActionContext through a stream. getServletContext (). getResourceAsStream ("/upload/UserLogin_7.27.apk");} public String execute () {return Action. SUCCESS ;} /************ [Implementation of Struts2 File Download ]***************** *************************** // If you directly write a link chain to the desired download on the file, in some cases, it is automatically opened in the browser by default. // this situation is not conducive to file download and permission control. Therefore, we do not use this method when downloading files. // we use the standard HTTP protocol to output a binary stream, which causes the browser to recognize the stream, it downloads files again // In fact, this method is related to the output. When you click the download link, a download information is generated. It is result-related // so go to The struts-default.xml to view the <result-type/> result type // Where <result-type name = "stream" class = "org. apache. struts2.dispatcher. streamResult "/> // In fact, The StreamResult class is used to download a file, the console prompts a socket exception ]********************************** * /// the error message is java.net. socketException: Connection reset by peer: socket write error // download itself is also a socket operation, so this exception is thrown. In fact, this exception can be ignored. This Exception will be thrown every time you download it. // After throws Exception on the getDownloadFile () method, this exception information will no longer be reported on the console./************* [source code snippets used to process the StreamResult class for File Download ]**** * ************************** // The org. apache. struts2.dispatcher. source code snippet of the StreamResult class // public class StreamResult extends StrutsResultSupport {// protected String contentType = "text/plain"; // protected String contentLength; // protected String contentDisposition = "inline ";/ /Protected String inputName = "inputStream"; // protected InputStream inputStream; // protected int bufferSize = 1024; /************ [analyze the three important attributes of the StreamResult class ]**************** * *********************** // here we mainly focus on the three attributes of the StreamResult class.: contentType, contentDisposition, and inputName // all attributes are stored in struts. after the xml configuration, Struts2 is automatically injected into the object. // The contentType is used to specify the type of the downloaded object, contentDisposition is used to specify the name of the downloaded object // In addition, bufferSize is used to set the download speed The size of the punch area. The default value is 1 kb, which is usually 1 kb by default. // In fact, these attributes are obtained based on the HTTP protocol. The HTTP Protocol specifies that these attributes must be used when downloading files. // The most critical attribute is the protected String inputName attribute, it is used to specify the IO stream of the actually downloaded file. // Therefore, an input stream must be returned in DownloadAction. Because when downloading, it is an operation to input files from the server /*************************** **************************************** ********************/}

2. the xml Code is as follows:

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd"><struts>  <package name="default" extends="struts-default" namespace="/">    <action name="download" class="com.wang.test.DownLoadPhoneFile">      <result name="success" type="stream">        <param name="contentType">application/vnd.ms-powerpoint</param>        <param name="contentDisposition">attachment;filename="UserLogin_7.27.apk"</param>        <param name="inputName">downloadFile</param>      </result>    </action>  </package></struts>

3. the JSP page code is as follows:

<% @ Page language = "java" import = "java. util. * "pageEncoding =" UTF-8 "%> <% String path = request. getContextPath (); String basePath = request. getScheme () + ": //" + request. getServerName () + ":" + request. getServerPort () + path + "/"; %> <! Doctype html public "-// W3C // dtd html 4.01 Transitional // EN"> 
I hope this article will help you with JSP program design.