Struts2实现单文件或多文件上传功能

2019-11-26 12:44:48

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一、简述

Struts2的文件上传其实也是通过拦截器来实现的，只是该拦截器定义为默认拦截器了，所以不用自己去手工配置，<interceptor name="fileUpload" class="org.apache.struts2.interceptor.FileUploadInterceptor"/>

二、指定用户上传文件的大小，有两种方式

1）默认是在default.properties 文件的 struts.multipart.maxSize=2097152 键值指定为2097152 也就是2M，通过计算 2097152/(1024*1024) = 2 M

那我们可以改变其默认值，只要在src目录下，新建一个 struts.properties 文件，指定上传大小如下：

一次上传只可以上传10M，不管一次上传多少个文件，按总和计算

2）在struts.xml文件中指定，如图：

其实name就对应struts.properties的键，value对应值

注意：如果即在struts.properties设定文件上传大小，又在struts.xml 设定文件上传大小，则struts.properties的优先级高于struts.xml，一般在一处指定上传大小即可，推荐 struts.properties

三、Struts2之单文件上传

1.fileupload.jsp

<%@ 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"> <html>  <head>  <base href="<%=basePath%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >    <title>My JSP 'fileupload.jsp' starting page</title>    <meta http-equiv="pragma" content="no-cache">  <meta http-equiv="cache-control" content="no-cache">  <meta http-equiv="expires" content="0">   <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">  <meta http-equiv="description" content="This is my page">  <!--  <link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >  -->   </head>   <body>   <!-- enctype 默认是 application/x-www-form-urlencoded -->   <form action="FileUpload2" enctype="multipart/form-data" method="post" >        用户名：<input type="text" name="usename"> <br/>     上传文件：<input type="file" name="file1"><br/>          <input type="submit" value="提交"/>     </form>        </body> </html>

2.具体处理上传的 FileUpload.java

package com.struts2.fileupload;  import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream;  import org.apache.struts2.ServletActionContext;  import com.opensymphony.xwork2.ActionSupport;  /**  * 单个文件上传  * @author Administrator  * 上传文件其实是上传了两份，  *  * 首先将上传的文件保存到 default.properties 文件中 struts.multipart.saveDir键指定的目录中  * 默认是空的  * 保存在 Tomcat 6.0/work/Catalina/localhost/struts2目录下以.tmp后缀名的文件  *  * 如果要在 struts.multipart.saveDir 指定目录， 则可以在 src文件夹下 建一个 struts.properties,  * 覆盖 default.properties 的某些键值  *  * 还有一份是 存放在自己设定的目录下  */ public class FileUpload extends ActionSupport {    private String usename ;  private File file1 ; //具体上传文件的 引用 , 指向临时目录中的临时文件  private String file1FileName ; // 上传文件的名字 ,FileName 固定的写法  private String file1ContentType ; //上传文件的类型， ContentType 固定的写法    public String getUsename() {   return usename;  }  public void setUsename(String usename) {   this.usename = usename;  }  public File getFile1() {   return file1;  }  public void setFile1(File file1) {   this.file1 = file1;  }  public String getFile1FileName() {   return file1FileName;  }  public void setFile1FileName(String file1FileName) {   this.file1FileName = file1FileName;  }  public String getFile1ContentType() {   return file1ContentType;  }  public void setFile1ContentType(String file1ContentType) {   this.file1ContentType = file1ContentType;  }    @Override  public String execute() throws Exception {   //获取文件存储路径   String path = ServletActionContext.getRequest().getRealPath("/upload");   //输出流   OutputStream os = new FileOutputStream(new File(path,file1FileName));   //输入流   InputStream is = new FileInputStream(file1);      byte[] buf = new byte[1024];   int length = 0 ;      while(-1 != (length = is.read(buf) ) )   {    os.write(buf, 0, length) ;   }   is.close();   os.close();      return SUCCESS;  }        }

3.最终显示结果的页面，filedemo.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <%@ taglib prefix="s" uri="/struts-tags" %>  <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %>  <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html>  <head>  <base href="<%=basePath%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >    <title>My JSP 'filedemo.jsp' starting page</title>    <meta http-equiv="pragma" content="no-cache">  <meta http-equiv="cache-control" content="no-cache">  <meta http-equiv="expires" content="0">   <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">  <meta http-equiv="description" content="This is my page">  <!--  <link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >  -->   </head>   <body>  上传成功: <br/>  usename: <s:property value="usename" /><br/>  file: <s:property value="file1FileName"/><br/>  contentType: <s:property value="file1ContentType"/>    </body> </html>

四、Struts2之多文件上传

1.fileupload.jsp

<%@ 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"> <html>  <head>  <base href="<%=basePath%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >    <title>My JSP 'fileupload.jsp' starting page</title>    <meta http-equiv="pragma" content="no-cache">  <meta http-equiv="cache-control" content="no-cache">  <meta http-equiv="expires" content="0">   <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">  <meta http-equiv="description" content="This is my page">  <!--  <link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >  -->   </head>   <body>   <!-- enctype 默认是 application/x-www-form-urlencoded -->   <form action="FileUpload2" enctype="multipart/form-data" method="post" >        用户名：<input type="text" name="usename"> <br/>     上传文件：<input type="file" name="file1"><br/>     上传文件： <input type="file" name="file1"><br/> <!-- 两个名字相同 都是file1 -->     <input type="submit" value="提交"/>     </form>        </body> </html>

两个上传文件的name属性值要是一样的，后台方便处理

2.具体处理上传文件的FileUpload2.java

多文件上传用集合的方式

package com.struts2.fileupload;  import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.util.List;  import org.apache.struts2.ServletActionContext;  import com.opensymphony.xwork2.ActionSupport;  /**  * 多文件上传，用集合的方式  * @author Administrator  *  */  public class FileUpload2 extends ActionSupport {    private String usename ;  private List<File> file1 ;  private List<String> file1FileName ;  private List<String> file1ContentType ;    public String getUsename() {   return usename;  }  public void setUsename(String usename) {   this.usename = usename;  }  public List<File> getFile1() {   return file1;  }  public void setFile1(List<File> file1) {   this.file1 = file1;  }  public List<String> getFile1FileName() {   return file1FileName;  }  public void setFile1FileName(List<String> file1FileName) {   this.file1FileName = file1FileName;  }  public List<String> getFile1ContentType() {   return file1ContentType;  }  public void setFile1ContentType(List<String> file1ContentType) {   this.file1ContentType = file1ContentType;  }    @Override  public String execute() throws Exception {      //获取文件存储路径   String path = ServletActionContext.getRequest().getRealPath("/upload");      for(int i = 0 ; i < file1.size() ; i++ )   {    OutputStream os = new FileOutputStream(new File(path,file1FileName.get(i)));        InputStream is = new FileInputStream(file1.get(i));        byte[] buf = new byte[1024];    int length = 0 ;        while(-1 != (length = is.read(buf) ) )    {     os.write(buf, 0, length) ;    }        is.close();    os.close();       }      return SUCCESS;  }  }

3.用于显示的界面filedemo.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <%@ taglib prefix="s" uri="/struts-tags" %>  <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %>  <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html>  <head>  <base href="<%=basePath%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >    <title>My JSP 'filedemo2.jsp' starting page</title>    <meta http-equiv="pragma" content="no-cache">  <meta http-equiv="cache-control" content="no-cache">  <meta http-equiv="expires" content="0">   <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">  <meta http-equiv="description" content="This is my page">  <!--  <link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >  -->   </head>   <body>     上传成功：<br/>   usename:<s:property value="usename"/><br/>     <!-- 遍历值 -->     <s:iterator value="file1FileName" id="f"> <!-- id是一个对象，目前是一个字符串集合 可任意命名 -->              文件:<s:property value="#f"/> <br/>     <!-- 这里也可以调用方法 <s:property value="#f.toUpperCase()"/> -->     </s:iterator>      </body> </html>

遍历集合的方式，用struts2提供的标签 iterator 可以实现

<s:iterator value="file1FileName" id="f"> <!-- id是一个对象，目前是一个字符串集合 可任意命名-->    文件:<s:property value="#f"/> <br/>     <!-- 这里也可以调用方法 <s:property value="#f.toUpperCase()"/> -->    toUpperCase()字符串的方法是把字母转为大写</s:iterator>

下载链接：

1）Servlet 文件上传点击打开链接
2）Struts2之下载点击打开链接

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