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1.文件上传
1）表单需要注意三点：
① 须把 HTML 表单的 enctype 属性设置为 multipart/form-data
②须把 HTML 表单的method 属性设置为 post
③需添加 <input type=“file”> 字段.
2）Struts2 的文件上传实际使用的是Common FileUpload 组件，导入jar包。commons-fileupload / commons-io
3）Struts2 进行文件上传需要使用FileUpload拦截器
4）基本的文件操作：直接在Action 中定义如下 3个属性，并提供对应的get / set方法
private File [fileFieldName]; //文件对应的file 对象
private String [fileFieldName]ContentType; // 文件类型
private String [fileFieldName]pptFileName; // 文件名
5）使用IO 流进行文件的上传
<?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> <!-- 配置国际化资源文件 -->
<constant name="strut2.custom.i18n.resouce" value="i18n"></constant> <constant name="struts.action.extension" value="action,do,"></constant>
<package name="default" namespace="/" extends="struts-default"> <action name="testUpload" class="com.jason.upload.app.UploadAction">
<result>/sucess.jsp</result>
</action> </package> </struts>
struts.xml
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body> <s:form action="testUpload" method="post" enctype="multipart/form-data">
<s:file name="ppt" label="PPTfile"></s:file>
<s:textfield name="pptDesc" label="PPTDesc"></s:textfield> <s:submit></s:submit>
</s:form> </body>
</html>
upload.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body> <h4> success page</h4>
</body>
</html>
sucess.jsp
package com.jason.upload.app; import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream; import javax.servlet.Servlet;
import javax.servlet.ServletContext; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.ActionSupport; public class UploadAction extends ActionSupport { /**
* @Fields:serialVersionUID
*/
private static final long serialVersionUID = 1L; private File ppt;
private String pptContentType;
private String pptFileName; public File getPpt() {
return ppt;
} public void setPpt(File ppt) {
this.ppt = ppt;
} public String getPptContentType() {
return pptContentType;
} public void setPptContentType(String pptContentType) {
this.pptContentType = pptContentType;
} public String getPptFileName() {
return pptFileName;
} public void setPptFileName(String pptFileName) {
this.pptFileName = pptFileName;
} @Override
public String execute() throws Exception { ServletContext servletContext = ServletActionContext.getServletContext(); String dir = servletContext.getRealPath("/files/" + pptFileName);
System.out.println(dir); FileOutputStream out = new FileOutputStream(dir);
FileInputStream in = new FileInputStream(ppt); byte[] buffer = new byte[1024];
int len = 0;
while((len = in.read(buffer)) != -1){
out.write(buffer, 0, len);
}
out.close();
in.close(); System.out.println(ppt);
System.out.println(pptContentType);
System.out.println(pptFileName);
return SUCCESS;
} }
UploadAction.java
2.相关问题
1）一次性上传过个文件？
若传递多个文件，则上述3个属性，可以改为list类型，多个文件的name 属性需要一致
<s:form action="testUpload" method="post" enctype="multipart/form-data">
<s:file name="ppt" label="PPTfile"></s:file>
<s:textfield name="pptDesc[0]" label="PPTDesc"></s:textfield> <s:file name="ppt" label="PPTfile"></s:file>
<s:textfield name="pptDesc[1]" label="PPTDesc"></s:textfield> <s:file name="ppt" label="PPTfile"></s:file>
<s:textfield name="pptDesc[2]" label="PPTDesc"></s:textfield> <s:file name="ppt" label="PPTfile"></s:file>
<s:textfield name="pptDesc[3]" label="PPTDesc"></s:textfield> <s:submit></s:submit>
</s:form>
private List<File> ppts;
private String pptContentType;
private String pptFileName;
2）对上传文件的限制？例如扩展名，内容类型，上传文件的大小？如果出错， 显示错误消息？消息可以定制?
Interceptor parameters: •maximumSize (optional) - the maximum size (in bytes) that the interceptor will allow a file reference to be set on the action. Note, this is not related to the various properties found in struts.properties. Default to approximately 2MB.
默认文件的最大值2M，上传的单个文件 •allowedTypes (optional) - a comma separated list of content types (ie: text/html) that the interceptor will allow a file reference to be set on the action. If none is specified allow all types to be uploaded.
允许上传的文件类型，多个使用 ',' 分割 •allowedExtensions (optional) - a comma separated list of file extensions (ie: .html) that the interceptor will allow a file reference to be set on the action. If none is specified allow all extensions to be uploaded.
允许的上传文件的类型，多个使用 ‘ , ’分割
定制文件上传错误消息
This interceptor will add several field errors, assuming that the action implements ValidationAware. These error messages are based on several i18n values stored in struts-messages.properties, a default i18n file processed for all i18n requests. You can override the text of these messages by providing text for the following keys: •struts.messages.error.uploading - a general error that occurs when the file could not be uploaded
文件上传出错的消息 •struts.messages.error.file.too.large - occurs when the uploaded file is too large
文件超过最大值的消息 •struts.messages.error.content.type.not.allowed - occurs when the uploaded file does not match the expected content types specified
文件内容不合法的消息 •struts.messages.error.file.extension.not.allowed - occurs when the uploaded file does not match the expected file extensions specified
文件扩展名不合法的消息
可以参考 org.apache.struts2. 下的 struts-message.properties ，可提供更多的定制信息
在 org.apache.struts2. 下的 default.properties 中有对文件上传总的大小的限制。可以使用常量的方式，修改限制：struts.multipart.maxSize = ?
1 <!-- 配置国际化资源文件 -->
2 <constant name="strut2.custom.i18n.resouce" value="i18n"></constant>
3
4 <constant name="struts.action.extension" value="action,do,"></constant>
5
6 <package name="default" namespace="/" extends="struts-default">
7
8 <interceptors>
9 <interceptor-stack name="jasonStack">
10 <interceptor-ref name="defaultStack">
11 <param name="fileUpload.maximumSize">2000</param>
12 <param name="fileUpload.allowedTypes">text/html,text/xml</param>
13 <param name="fileUpload.allowedExtensions">html,ppt,xml</param>
14 </interceptor-ref>
15 </interceptor-stack>
16 </interceptors>
17
18
19 <default-interceptor-ref name="jasonStack"></default-interceptor-ref>
20 <action name="testUpload" class="com.jason.upload.app.UploadAction">
21 <result>/sucess.jsp</result>
22 </action>
23
24 </package>
25
struts.xml
struts.messages.error.uploading=\u6587\u4EF6\u4E0A\u4F20\u51FA\u9519\u7684\u6D88\u606F
struts.messages.error.file.too.large=\u6587\u4EF6\u8D85\u8FC7\u6700\u5927\u503C\u7684\u6D88\u606F
struts.messages.error.content.type.not.allowed=\u6587\u4EF6\u5185\u5BB9\u4E0D\u5408\u6CD5\u7684\u6D88\u606F
struts.messages.error.file.extension.not.allowed=\u6587\u4EF6\u6269\u5C55\u540D\u4E0D\u5408\u6CD5\u7684\u6D88\u606F
i18n.properties
2.文件的下载
1）struts2 中使用 type="stream" 的result 进行下载即可：具体细节 /struts-2.3.15.3-all/struts-2.3.15.3/docs/WW/docs/stream-result.html
2）Struts 专门为文件下载提供了一种 Stream 结果类型. 在使用一个 Stream 结果时, 不必准备一个 JSP 页面.
3）Stream 结果类型可以设置如下参数:(以下参数可以在Action中以 getter 方法的方式提供)
- contentType：被下载的文件的 MIME 类型。默认值为 text/plain
- contentLength：被下载的文件的大小，以字节为单位
- contentDisposition： 可以设置下载文件名的ContentDispositon 响应头，默认值为 inline，通常设置为如下格式： attachment;filename="document.pdf".
- inputName：Action 中提供的文件的输入流。默认值为 inputStream
- bufferSize：文件下载时缓冲区的大小。默认值为 1024
- allowCaching ：文件下载时是否允许使用缓存。默认值为 true
- contentCharSet：文件下载时的字符编码。
4）Stream 结果类型的参数可以在 Action 以属性的方式覆盖
download.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<a href="testDownload">Down Load</a>
</body>
</html>
DownLoadAction.java
对于
contentType
contentLength
contentDisposition
inputStream
我们需要在对应的Action 中声明一个变量 且提供 getter方法
package com.jason.upload.app; import java.io.FileInputStream;
import java.io.InputStream; import javax.servlet.ServletContext; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.ActionSupport; public class DownLoadAction extends ActionSupport { /**
* @Fields:serialVersionUID
*/
private static final long serialVersionUID = 1L; private String contentType;
private long contentLength;
private String contentDisposition;
private InputStream inputStream; public String getContentDisposition() {
return contentDisposition;
} public long getContentLength() {
return contentLength;
} public String getContentType() {
return contentType;
} public InputStream getInputStream() {
return inputStream;
}
@Override
public String execute() throws Exception { //1.确定各成员的值
contentType = "text/html";
44 contentDisposition = "attachment;filename='a.html'";
45
46 ServletContext servletContext = ServletActionContext.getServletContext();
47 String fileName = servletContext.getRealPath("/files/a.html");
48 inputStream = new FileInputStream(fileName);
49 contentLength = inputStream.available();
return super.execute();
} }
struts.xml
<?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>
<action name="testDownload" class="com.jason.upload.app.DownLoadAction">
<result type="stream">
<param name="bufferSize">2048</param>
</result>
</action>
</package> </struts>