struts2学习笔记6-上传与下载文件
Struts2上传文件要用到commons-fileupload和commons-io这两个组件先看一个用Servlet而不用Struts2上传的例子吧
页面
<form action="/struts2/UploadServlet" method="post" enctype="multipart/form-data">信息:<input type="text" name="info"/><br/>文件:<input type="file" name="file"/><br/><input type="submit" name="submit"/></form>
Servlet代码
import java.io.File;import java.io.IOException;import java.util.List;import javax.servlet.RequestDispatcher;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.commons.fileupload.FileItem;import org.apache.commons.fileupload.FileUploadException;import org.apache.commons.fileupload.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;public class UploadServlet extends HttpServlet {private static final long serialVersionUID = 1L;public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//设置编码request.setCharacterEncoding("utf-8");//创建工厂DiskFileItemFactoryDiskFileItemFactory factory = new DiskFileItemFactory();//获得当前项目的Path(这里是当前项目下的/upload/fileupload的路径)String path = request.getRealPath("/upload/fileupload");//设置临时文件的存放路径factory.setRepository(new File(path));//设置临时文件的大小factory.setSizeThreshold(1024*1024*2);//创建ServletFileUpload对象,用工厂ServletFileUpload upload = new ServletFileUpload(factory);try {//调用ServletFileUpload对象的parseRequest方法获得一个装了FileItem的ListList<FileItem> list = upload.parseRequest(request);//每个FileItem里面封装了页面表单的信息(一个)for(FileItem fileItem : list){//ifFormField表示是平常的表单(非file类型的)if(fileItem.isFormField()){//获得表单名字,如<input type="text" name="info"/>这个里面的infoString name = fileItem.getFieldName();//获得值value,并设置为UTF-8编码String value = fileItem.getString("utf-8");request.setAttribute(name, value);}else{//获得表单名字,如<input type="file" name="file"/>这个里面的infoString name = fileItem.getFieldName();//获得名字,这个和非file表单不一样String value = fileItem.getName();//获得最后一个\的位置int i = value.lastIndexOf("\\");//在这个位置上加1,获得这个位置之后的Stringvalue = value.substring(i+1);request.setAttribute(name, value);//组件已经封装好的write方法,当然也可以用request.getInputStream()来完成fileItem.write(new File(path,value));}}} catch (FileUploadException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();}//因为要传参数,所以转发RequestDispatcher dispatcher = request.getRequestDispatcher("/upload/success.jsp");dispatcher.forward(request, response);}}
用Struts2上传文件(多文件，一个文件和多个文是一样的)
先看页面，用了struts2的标签
<%@ taglib prefix="s" uri="/struts-tags" %><s:form method="post" action="upload" enctype="multipart/form-data"><s:textfield name="username" label="username"></s:textfield><s:password name="password" label="password"></s:password><s:file name="fileUpload" label="filePath"></s:file><s:file name="fileUpload" label="filePath"></s:file><s:file name="fileUpload" label="filePath"></s:file><s:file name="fileUpload" label="filePath"></s:file><s:submit value="Submit"></s:submit></s:form>
再看Action
public class FileUploadAction extends ActionSupport implementsApplicationAware, SessionAware, ServletRequestAware,ServletResponseAware {private static final long serialVersionUID = 1L;private Map application;private Map session;private HttpServletRequest request;private HttpServletResponse response;private String username;private String password;private List<File> fileUpload;private List<String> fileUploadFileName;private List<String> fileUploadContentType;@Overridepublic String execute() throws Exception {for(int i = 0;i<fileUpload.size();i++ ){InputStream is = new FileInputStream(this.fileUpload.get(i));String path = this.request.getRealPath("/upload/file");OutputStream os = new FileOutputStream(new File(path,this.fileUploadFileName.get(i)));byte[] b = new byte;int length = 0;while((length = is.read(b))>0){os.write(b, 0, length);}System.out.println("path = " + path);System.out.println("fileName" + this.fileUploadFileName.get(i) + "contentType" +this.fileUploadContentType.get(i));os.close();is.close();}return Action.SUCCESS;}
struts.xml配置文件
<action name="upload" class="com.langhua.action.FileUploadAction"><result name="success">/upload/uploadsuccess.jsp</result><interceptor-ref name="defaultStack"></interceptor-ref></action>
最后上传成功展示页面
username:${username}<br/>password:${password}<br/>fileName:${fileUploadFileName}<br/>fileContentType:${fileUploadContentType}
使用Converter转换Action里面的fileUploadFileName,fileUploadContentType
public class UploadConverter extends StrutsTypeConverter {@Overridepublic Object convertFromString(Map context, String[] values, Class toClass) {List<String> list = new ArrayList<String>();for(String value : values){list.add(value);}return list;}@Overridepublic String convertToString(Map context, Object o) {List<String> list = (List<String>) o;StringBuffer sb = new StringBuffer();for(String value : list){sb.append(value).append(" ");System.out.println(value);}return sb.toString();}}
再配置上
fileUploadFileName=com.langhua.converter.UploadConverterfileUploadContentType=com.langhua.converter.UploadConverter
页面使用struts2的标签就转换了
fileName:<s:property value="fileUploadFileName"/><br/>fileContentType:<s:property value="fileUploadContentType"/><br/>
还可在struts.xml里面配置
<constant name="struts.multipart.saveDir" value="c:/temp"></constant><constant name="struts.multipart.maxSize" value="209715200"></constant>
设置上传时temp文件放的位置和最大文件的大小
还有其它的可以配置，他们都在org.apache.struts2.default.properties里面有的
比如说改连结的后缀名,编码，用的上传文件的类库
struts.i18n.encoding=UTF-8struts.multipart.parser=jakartastruts.action.extension=action
Struts2下载文件
<action name="download" class="com.langhua.action.DownloadAction" method="downloadFile"><!--type 为 stream 应用 StreamResult 处理--><result name="success" type="stream"><!--默认为 text/plain--><!-- <param name="contentType">image/pjpeg</param> --><!-- 默认为 inline(在线打开)，设置为 attachment 将会告诉浏览器下载该文件，filename 指定下载文 件保有存时的文件名，若未指定将会是以浏览的页面名作为文件名，如以 download.action 作为文件名， 这里使用的是动态文件名，${fileName}, 它将通过 Action 的 getFileName() 获得文件名 --><param name="contentDisposition">attachment;filename="${filename}"</param><!-- 默认就是 inputStream，它将会指示 StreamResult 通过 inputName 属性值的 getter 方法， 比如这里就是 getInputStream() 来获取下载文件的内容，意味着你的 Action 要有这个方法 --><param name="inputName">inputStram</param><param name="bufferSize">4096</param><!-- 输出时缓冲区的大小 --></result></action>
type为stream的参数来自这个类
package org.apache.struts2.dispatcher;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;}
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