通過struts-default.xml里面的fileUpload攔截器實現(xiàn)文件上傳與下載豌注。
<interceptor name="fileUpload" class="org.apache.struts2.interceptor.FileUploadInterceptor"/>
1.FileUploadInterceptor里面的相關(guān)方法
/**
* Sets the allowed extensions
* 限制運行的文件的擴展名
* @param allowedExtensions A comma-delimited list of extensions
*/
public void setAllowedExtensions(String allowedExtensions) {
allowedExtensionsSet = TextParseUtil.commaDelimitedStringToSet(allowedExtensions);
}
/**
* Sets the allowed mimetypes
* 設(shè)置允許的mimetype
* @param allowedTypes A comma-delimited list of types
*/
public void setAllowedTypes(String allowedTypes) {
allowedTypesSet = TextParseUtil.commaDelimitedStringToSet(allowedTypes);
}
/**
* Sets the maximum size of an uploaded file
* 設(shè)置上傳的最大文件大小
* @param maximumSize The maximum size in bytes
*/
public void setMaximumSize(Long maximumSize) {
this.maximumSize = maximumSize;
}
/* (non-Javadoc)
* @see com.opensymphony.xwork2.interceptor.Interceptor#intercept(com.opensymphony.xwork2.ActionInvocation)
*/
public String intercept(ActionInvocation invocation) throws Exception {
ActionContext ac = invocation.getInvocationContext();
HttpServletRequest request = (HttpServletRequest) ac.get(ServletActionContext.HTTP_REQUEST);
if (!(request instanceof MultiPartRequestWrapper)) {
if (LOG.isDebugEnabled()) {
ActionProxy proxy = invocation.getProxy();
LOG.debug(getTextMessage("struts.messages.bypass.request", new Object[]{proxy.getNamespace(), proxy.getActionName()}, ac.getLocale()));
}
return invocation.invoke();
}
ValidationAware validation = null;
Object action = invocation.getAction();
if (action instanceof ValidationAware) {
validation = (ValidationAware) action;
}
MultiPartRequestWrapper multiWrapper = (MultiPartRequestWrapper) request;
if (multiWrapper.hasErrors()) {
for (String error : multiWrapper.getErrors()) {
if (validation != null) {
validation.addActionError(error);
}
if (LOG.isWarnEnabled()) {
LOG.warn(error);
}
}
}
// bind allowed Files
Enumeration fileParameterNames = multiWrapper.getFileParameterNames();
while (fileParameterNames != null && fileParameterNames.hasMoreElements()) {
// get the value of this input tag
// 獲取標(biāo)簽名file1
String inputName = (String) fileParameterNames.nextElement();
// get the content type
String[] contentType = multiWrapper.getContentTypes(inputName);
if (isNonEmpty(contentType)) {
// get the name of the file from the input tag
String[] fileName = multiWrapper.getFileNames(inputName);
if (isNonEmpty(fileName)) {
// get a File object for the uploaded File
File[] files = multiWrapper.getFiles(inputName);
if (files != null && files.length > 0) {
List<File> acceptedFiles = new ArrayList<File>(files.length);
List<String> acceptedContentTypes = new ArrayList<String>(files.length);
List<String> acceptedFileNames = new ArrayList<String>(files.length);
String contentTypeName = inputName + "ContentType";
String fileNameName = inputName + "FileName";
for (int index = 0; index < files.length; index++) {
if (acceptFile(action, files[index], fileName[index], contentType[index], inputName, validation, ac.getLocale())) {
acceptedFiles.add(files[index]);
acceptedContentTypes.add(contentType[index]);
acceptedFileNames.add(fileName[index]);
}
}
if (!acceptedFiles.isEmpty()) {
Map<String, Object> params = ac.getParameters();
params.put(inputName, acceptedFiles.toArray(new File[acceptedFiles.size()]));
params.put(contentTypeName, acceptedContentTypes.toArray(new String[acceptedContentTypes.size()]));
params.put(fileNameName, acceptedFileNames.toArray(new String[acceptedFileNames.size()]));
}
}
} else {
if (LOG.isWarnEnabled()) {
LOG.warn(getTextMessage(action, "struts.messages.invalid.file", new Object[]{inputName}, ac.getLocale()));
}
}
} else {
if (LOG.isWarnEnabled()) {
LOG.warn(getTextMessage(action, "struts.messages.invalid.content.type", new Object[]{inputName}, ac.getLocale()));
}
}
}
// invoke action
return invocation.invoke();
}
2.文件上傳與下載實例
FileUpload:文件上傳Action
import java.io.File;
import org.apache.commons.io.FileUtils;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class FileUpload extends ActionSupport {
// 對應(yīng)表單：<input type="file" name="file1">
private File file1;
// 文件名
private String file1FileName;
// 文件的類型(MIME)
private String file1ContentType;
public void setFile1(File file1) {
this.file1 = file1;
}
public void setFile1FileName(String file1FileName) {
this.file1FileName = file1FileName;
}
public void setFile1ContentType(String file1ContentType) {
this.file1ContentType = file1ContentType;
}
@Override
public String execute() throws Exception {
/****** 拿到上傳的文件崖面，進(jìn)行處理 ******/
// 把文件上傳到upload目錄
// 獲取上傳的目錄路徑
String path = ServletActionContext.getServletContext().getRealPath(
"/upload");
// 創(chuàng)建目標(biāo)文件對象
File destFile = new File(path, file1FileName);
// 把上傳的文件孝鹊，拷貝到目標(biāo)文件中
FileUtils.copyFile(file1, destFile);
return SUCCESS;
}
}
DownAction:文件列表展示和下載Action
import java.io.File;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.Map;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class DownAction extends ActionSupport {
/*************1. 顯示所有要下載文件的列表*********************/
public String list() throws Exception {
//得到upload目錄路徑
String path = ServletActionContext.getServletContext().getRealPath("/upload");
// 目錄對象
File file = new File(path);
// 得到所有要下載的文件的文件名
String[] fileNames = file.list();
// 保存
ActionContext ac = ActionContext.getContext();
// 得到代表request的map (第二種方式)
Map<String,Object> request= (Map<String, Object>) ac.get("request");
request.put("fileNames", fileNames);
return "list";
}
/*************2. 文件下載*********************/
// 1. 獲取要下載的文件的文件名
private String fileName;
public void setFileName(String fileName) {
// 處理傳入的參數(shù)中問題(get提交)
try {
fileName = new String(fileName.getBytes("ISO8859-1"),"UTF-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
// 把處理好的文件名隘马，賦值
this.fileName = fileName;
}
//2. 下載提交的業(yè)務(wù)方法 (在struts.xml中配置返回stream)
public String down() throws Exception {
return "download";
}
// 3. 返回文件流的方法
public InputStream getAttrInputStream(){
return ServletActionContext.getServletContext().getResourceAsStream("/upload/" + fileName);
}
// 4. 下載顯示的文件名（瀏覽器顯示的文件名）
public String getDownFileName() {
// 需要進(jìn)行中文編碼
try {
fileName = URLEncoder.encode(fileName, "UTF-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
return fileName;
}
}
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>
<package name="upload_" extends="struts-default">
<!-- 注意： action 的名稱不能用關(guān)鍵字"fileUpload" -->
<action name="fileUploadAction" class="cn.itcast.e_fileupload.FileUpload">
<!-- 限制運行上傳的文件的類型 -->
<interceptor-ref name="defaultStack">
<!-- 限制運行的文件的擴展名 -->
<param name="fileUpload.allowedExtensions">txt,jpg,jar</param>
<!-- 限制運行的類型 【與上面同時使用打月，取交集】
<param name="fileUpload.allowedTypes">text/plain</param>
-->
</interceptor-ref>
<result name="success">/e/success.jsp</result>
<!-- 配置錯誤視圖 -->
<result name="input">/e/error.jsp</result>
</action>
<action name="down_*" class="cn.itcast.e_fileupload.DownAction" method="{1}">
<!-- 列表展示 -->
<result name="list">/e/list.jsp</result>
<!-- 下載操作 -->
<result name="download" type="stream">
<!-- 運行下載的文件的類型:指定為所有的二進(jìn)制文件類型 -->
<param name="contentType">application/octet-stream</param>
<!-- 對應(yīng)的是Action中屬性： 返回流的屬性【其實就是getAttrInputStream()】 -->
<param name="inputName">attrInputStream</param>
<!-- 下載頭肿仑，包括：瀏覽器顯示的文件名 -->
<param name="contentDisposition">attachment;filename=${downFileName}</param>
<!-- 緩沖區(qū)大小設(shè)置 -->
<param name="bufferSize">1024</param>
</result>
</action>
</package>
</struts>
上傳頁面表單：
<form action="${pageContext.request.contextPath }/fileUploadAction" method="post" enctype="multipart/form-data">
用戶名:<input type="text" name="userName"><br/>
<%--name的取名file1要和上傳Action里面的字段對應(yīng)--%>
文件:<input type="file" name="file1"><br/>
<input type="submit" value="上傳">
</form>
文件列表和下載頁面：
<table border="1" align="center">
<tr>
<td>編號</td>
<td>文件名</td>
<td>操作</td>
</tr>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<c:forEach var="fileName" items="${fileNames}" varStatus="vs">
<tr>
<td>${vs.count }</td>
<td>${fileName }</td>
<td>
<!-- 構(gòu)建一個url -->
<c:url var="url" value="down_down">
<c:param name="fileName" value="${fileName}"></c:param>
</c:url>
<a href="${url }">下載</a>
</td>
</tr>
</c:forEach>
</table>
