Java框架Struts2实现图片上传功能

2019-11-26 09:41:29

字体：大中小

来源：转载

供稿：网友

Struts 2 框架为处理文件上传提供了内置支持，它使用“在 HTML 中基于表单的文件上传”。当上传一个文件时，它通常会被存储在一个临时目录中，而且它们应该由 Action 类进行处理或移动到一个永久的目录，用来确保数据不丢失。服务器在恰当的位置可能有一个安全策略，它会禁止你写到除了临时目录以外的目录，而且这个目录属于你的web应用应用程序。

通过预定义的名为文件上传的拦截器，Struts 的文件上传是可能的，这个拦截器在 org.apache.struts2.interceptor.FileUploadInterceptor 类是可用的，而且是 defaultStack 的一部分。

创建视图文件

让我们开始创建需要浏览和上传选定的文件的视图。因此，让我们创建一个带有简单的 HTML 上传表单的 index.jsp，它允许用户上传文件：（表单的编码类型设置为multipart/form-data）

<%-- Created by IntelliJ IDEA. User: yzjxiaoyue Date: 2017/7/28 Time: 19:11 To change this template use File | Settings | File Templates.--%><%@ page language="java" contentType="text/html; charset=utf-8"     pageEncoding="utf-8"%><%@ taglib prefix="s" uri="/struts-tags"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"><html><head>  <title>File Upload</title></head><body><form action="upload" method="post" enctype="multipart/form-data">  <label for="myFile">Upload your file</label>  <input type="file" name="myFile" id="myFile"/>  <input type="submit" value="Upload"/></form></body></html>

之后创建success.jsp页面：

<%-- Created by IntelliJ IDEA. User: yzjxiaoyue Date: 2017/7/28 Time: 19:14 To change this template use File | Settings | File Templates.--%><%@ page contentType="text/html; charset=UTF-8" %><%@ taglib prefix="s" uri="/struts-tags" %><html><head>  <title>File Upload Success</title></head><body>You have successfully uploaded <s:property value="myFileFileName"/></body></html>

创建error.jsp页面

<%-- Created by IntelliJ IDEA. User: yzjxiaoyue Date: 2017/7/28 Time: 20:05 To change this template use File | Settings | File Templates.--%><%@ page contentType="text/html; charset=UTF-8" %><%@ taglib prefix="s" uri="/struts-tags" %><html><head>  <title>File Upload Error</title></head><body>There has been an error in uploading the file.</body></html>

创建 action 类

接下来让我们创建一个称为 uploadFile.java 的 Java 类，它负责上传文件，并且把这个文件存储在一个安全的位置：

package com.action; import com.opensymphony.xwork2.ActionSupport;import org.apache.commons.io.FileUtils; import java.io.File;import java.io.IOException;public class uploadFile extends ActionSupport{  private File myFile;   public File getMyFile() {    return myFile;  }  public void setMyFile(File myFile) {    this.myFile = myFile;  }   private String myFileContentType;   private String myFileFileName;   private String destPath;   public String execute()  {     /* Copy file to a safe location */    destPath = "E://Program Files//apache-tomcat-9.0.0//apache-tomcat-9.0.0.M22//work//";    try{      System.out.println("Src File name: " + myFile);      System.out.println("Dst File name: " + myFileFileName);      File destFile = new File(destPath, myFileFileName);      FileUtils.copyFile(myFile, destFile);    }catch(IOException e){      e.printStackTrace();      return ERROR;    }    return SUCCESS;  }    public String getMyFileContentType() {    return myFileContentType;  }  public void setMyFileContentType(String myFileContentType) {    this.myFileContentType = myFileContentType;  }  public String getMyFileFileName() {    return myFileFileName;  }  public void setMyFileFileName(String myFileFileName) {    this.myFileFileName = myFileFileName;  }}

配置文件

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts PUBLIC    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"    "http://struts.apache.org/dtds/struts-2.3.dtd"> <struts>  <constant name="struts.devMode" value="true"/>  <constant name="struts.multipart.maxSize" value="10000000"/>   <constant name="struts.multipart.saveDir" value="/tmp"/>  <constant name="struts.custom.i18n.resources" value="struts"></constant>  <package name="default" namespace="/" extends="struts-default">    <action name="upload" class="com.action.uploadFile">      <!--<interceptor-ref name="basicStack"/>-->      <interceptor-ref name="defaultStack"/>      <interceptor-ref name="fileUpload">        <param name="allowedTypes">image/jpeg,image/jpg,image/gif</param>      </interceptor-ref>      <result name="success">/success.jsp</result>      <result name="error">/error.jsp</result>    </action>  </package></struts>

界面截图