通过struts-default.xml里面的fileUpload拦截器实现文件上传与下载。
1.FileUploadInterceptor里面的相关方法
/**
* Sets the allowed extensions
* 限制运行的文件的扩展名
* @param allowedExtensions A comma-delimited list of extensions
*/
public void setAllowedExtensions(String allowedExtensions) {
allowedExtensionsSet = TextParseUtil.commaDelimitedStringToSet(allowedExtensions);
}
/**
* Sets the allowed mimetypes
* 设置允许的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
* 设置上传的最大文件大小
* @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
// 获取标签名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 acceptedFiles = new ArrayList(files.length);
List acceptedContentTypes = new ArrayList(files.length);
List acceptedFileNames = new ArrayList(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 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.文件上传与下载实例
FileUpload:文件上传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 {
// 对应表单：
private File file1;
// 文件名
private String file1FileName;
// 文件的类型(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 {
/****** 拿到上传的文件，进行处理 ******/
// 把文件上传到upload目录
// 获取上传的目录路径
String path = ServletActionContext.getServletContext().getRealPath(
"/upload");
// 创建目标文件对象
File destFile = new File(path, file1FileName);
// 把上传的文件，拷贝到目标文件中
FileUtils.copyFile(file1, destFile);
return SUCCESS;
}
}
DownAction:文件列表展示和下载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. 显示所有要下载文件的列表*********************/
public String list() throws Exception {
//得到upload目录路径
String path = ServletActionContext.getServletContext().getRealPath("/upload");
// 目录对象
File file = new File(path);
// 得到所有要下载的文件的文件名
String[] fileNames = file.list();
// 保存
ActionContext ac = ActionContext.getContext();
// 得到代表request的map (第二种方式)
Map request= (Map) ac.get("request");
request.put("fileNames", fileNames);
return "list";
}
/*************2. 文件下载*********************/
// 1. 获取要下载的文件的文件名
private String fileName;
public void setFileName(String fileName) {
// 处理传入的参数中问题(get提交)
try {
fileName = new String(fileName.getBytes("ISO8859-1"),"UTF-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
// 把处理好的文件名，赋值
this.fileName = fileName;
}
//2. 下载提交的业务方法 (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. 下载显示的文件名（浏览器显示的文件名）
public String getDownFileName() {
// 需要进行中文编码
try {
fileName = URLEncoder.encode(fileName, "UTF-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
return fileName;
}
}
配置文件：
txt,jpg,jar
/e/success.jsp
/e/error.jsp
/e/list.jsp
application/octet-stream
attrInputStream
attachment;filename=${downFileName}
1024
上传页面表单：
文件列表和下载页面：
编号
文件名
操作
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
${vs.count }
${fileName }
下载