文件上传及下载
一、要实现文件上传，需在项目中添加两个jar文件
Jsp页面
<h2>单个文件上传</h2> <s:form action="upload.action" enctype="multipart/form-data" method="post"> <s:textfield name="title" label="标题"/> <s:file name="upload" label="选择文件"/><br/> <s:submit name="submit" value="上传文件"></s:submit> </s:form>
Action类
public class UploadAction extends ActionSupport{ //封装上传文件属性 private File upload; //封装上传文件的类型 private String uploadContentType; //封装上传文件名称 private String uploadFileName; //获取文件上传的路径 private String savePath; @Override public String execute() throws Exception { byte[] buffer=new byte[1024]; //读取文件 FileInputStream fis=new FileInputStream(getUpload()); //保存文件 FileOutputStream fos=new FileOutputStream(getSavePath()+"\\"+this.getUploadFileName()); int length=fis.read(buffer); while(length>0){ //每次写入length长度的内容 fos.write(buffer,0,length); length=fis.read(buffer); } fis.close(); fos.flush(); fos.close(); return SUCCESS; } //获取文件上传的保存路径 通过读取存放目录获得保存路径 public String getSavePath() { return ServletActionContext.getServletContext().getRealPath(savePath); }
在Action中使用了三个属性封装文件信息：
File类型的XXX属性，与表单的File控件的name属性一样，用于封装File控件对应的文件内容
String类型的xxxFileName属性，该属性名称由前面的File类型属性和FileName组合，是固定的语法，是封装File控件对应文件的文件名
String类型的XXXContentType属性，同样由xxx属性和ContentType组合而成，是固定语法，封装File控件对应文件的文件类型
配置Action:
<?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> <package name="default" namespace="/" extends="struts-default"> <!-- 文件上传 --> <action name="upload" class="cn.happy.action.UploadAction"> <!-- 通过param参数设置保存目录的路径 --> <param name="savePath">/upload</param> <result name="success">ok.jsp</result> </action> </package> </struts>
上传成功后的结果页面：植入的value是Action类中所对应的实体类属性
您所上传的文件是:<s:property value="uploadFileName"/><br/> 文件类型：<s:property value="uploadContentType"/>
页面运行效果：
多个文件上传
只需在上传Action中将原本处理单个文件的操作改成对集合操作即可。
其他的都跟单个上传的一样
页面
<!-- 多个文件上传 -->
<action name="someupload" class="cn.action.SomeUploadAction">
<!-- 通过param参数设置保存目录的路径 -->
<param name="savePath">/upload</param>
<result name="success">success.jsp</result>
</action>
开发实现文件上传的Action
package cn.action; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.ActionSupport; public class SomeUploadAction extends ActionSupport { //封装上传文件属性 private File[] upload; //封装上传文件的类型 private String[] uploadContentType; //封装上传文件名称 private String[] uploadFileName; //封装文件上传的路径 private String savePath; public String execute() throws Exception{ byte[] buffer=new byte[1024]; for (int i = 0; i < upload.length; i++) { FileInputStream fis=new FileInputStream(getUpload()[i]); FileOutputStream fos=new FileOutputStream(getSavePath()+"\\"+this.getUploadFileName()[i]); int length=fis.read(buffer); while(length>0){ fos.write(buffer, 0, length); length=fis.read(buffer); } fos.flush(); fos.close(); fis.close(); } return SUCCESS; } public File[] getUpload() { return upload; } public void setUpload(File[] upload) { this.upload = upload; } public String[] getUploadContentType() { return uploadContentType; } public void setUploadContentType(String[] uploadContentType) { this.uploadContentType = uploadContentType; } public String[] getUploadFileName() { return uploadFileName; } public void setUploadFileName(String[] uploadFileName) { this.uploadFileName = uploadFileName; } public String getSavePath() { return ServletActionContext.getServletContext().getRealPath(savePath); } public void setSavePath(String savePath) { this.savePath = savePath; } }
配置Action
<!-- 多个文件上传 -->
<action name="someupload" class="cn.action.SomeUploadAction">
<!-- 通过param参数设置保存目录的路径 -->
<param name="savePath">/upload</param>
<result name="success">success.jsp</result>
</action>
文件下载
文件下载需要InputStream，首先在文件下载Action中提供一个获得InputStream的方法，通过输入流可以获取希望下载的文件内容
package cn.action; import java.io.BufferedInputStream; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.InputStream; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.ActionSupport; public class FileDownAction extends ActionSupport { //读取下载文件的目录 private String inputPath; //下载文件的文件名 private String fileName; //读取下载文件的输入流 private InputStream inputStream; //下载文件的类型 private String conetntType; public String execute(){ return SUCCESS; } public String getInputPath() { return inputPath; } public void setInputPath(String inputPath) { this.inputPath = inputPath; } public String getFileName() { return fileName; } public void setFileName(String fileName) { this.fileName = fileName; } //创建InputStream输入流 public InputStream getInputStream() throws Exception { String path=ServletActionContext.getServletContext().getRealPath(inputPath); BufferedInputStream stream = new BufferedInputStream(new FileInputStream(path+"\\"+fileName)); return stream; } public void setInputStream(InputStream inputStream) { this.inputStream = inputStream; } public String getConetntType() { return conetntType; } public void setConetntType(String conetntType) { this.conetntType = conetntType; } }
通过Context得到下载文件的实际路径，构建一个InputStream输入流实现文件的下载读取。
在配置文件中，同样对Action进行配置，并对stream结果类型的参数进行设置。
<!-- download指定的Action -->
<action name="download" class="cn.action.FileDownAction">
<param name="inputPath">/upload</param>
<result name="success" type="stream">
<param name="contentType">application/octet-stream</param>
<param name="inputName">inputStream</param>
<param name="contentDisposition">
attachment;filename="${fileName}"
</param>
<param name="bufferSize">4096</param>
</result>
</action>
