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Struts2使用开源项目Apache Jakarta Commons FileUpload和内建的FileUploadInterceptor拦截器实现文件上传，所需的jar包如下：
commons-logging-1.1.jar
freemarker-2.3.8.jar
ognl-2.6.11.jar
struts2-core-2.0.6.jar
xwork-2.0.1.jar
commons-io-1.3.1.jar
commons-fileupload-1.2.jar
一：单文件止传
1.文件上传页面 fileUpload.jsp
<body>
<s:form action="/fileUpload.action" method="post" enctype="multipart/form-data">
<s:fielderror></s:fielderror>
<s:file name="myFile" label="图片上传"></s:file>
<s:textfield name="caption" label="标题"></s:textfield>
<s:submit value="提交"></s:submit>
</s:form>
</body>
2.创建FileUploadAction.java:处理文件上传
public class FileUploadAction extends ActionSupport {
private static final int BUFFER_SIZE = 10*1024;
private File myFile; //对应页面文件name
private String contentType; //文件类型
private String fileName; //文件名
private String imageFileName; //
private String caption; //标题
public void setMyFileContentType(String contentType){
this.contentType = contentType;
}
public void setMyFileFileName(String fileName){
this.fileName = fileName;
}
public void setMyFile(File myFile){
this.myFile = myFile;
}
public String getImageFileName(){
return imageFileName;
}
public String getCaption(){
return caption;
}
public void setCaption(){
this.caption = caption;
}
public static void copy(File src,File dst){
InputStream in = null; //输入流
OutputStream out = null;//输出流
try {
in = new BufferedInputStream(new FileInputStream(src),BUFFER_SIZE);
out = new BufferedOutputStream(new FileOutputStream(dst),BUFFER_SIZE);
byte[] buffer = new byte[BUFFER_SIZE];
while (in.read(buffer)>0 ) {
out.write(buffer);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
if(in!=null){
try {
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(out!=null){
try {
out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
public static String getExtention(String fileName){
int pos = fileName.lastIndexOf(".");
return fileName.substring(pos);
}
@Override
public String execute() throws Exception {
//创建新的文件名（系统时间＋原文件扩展名）
Date date = new Date();
String newFileName = this.getExtention(fileName);
imageFileName = date.getTime()+newFileName;
//创建新文件保存路径
File imageFile = new File(ServletActionContext.getServletContext().getRealPath("/UploadImages")+"/"+imageFileName);
this.copy(myFile, imageFile);
return SUCCESS;
}
}
在fileupload.jsp中，只有doc一个字段，而FileUploadAction.java中，却有三个字段，Struts2怎么通过页面的 一个字段设置Action里的三个字段呢？没错，这就是FileUploadInterceptor的功劳了！你所要做的只是按照一定的样式命名这三个字 段的set方法，而字段名可以任意命名。第一个File类型的字段的set方法还是以常规的方式命名，另两个String类型的字段的set方法必须分别 以“File字段的set方法名+FileName”和“File字段的set方法名+ContentType”来命名。
3.struts.xml配置
<!-- 文件上传配置 -->
<package name="fileupload" namespace="/" extends="struts-default">
<action name="fileUpload" class="fileupload.FileUploadAction">
<interceptor-ref name="fileUpload">
<param name="allowedTypes">
image/bmp,image/png,image/gif,image/jpeg
</param>
</interceptor-ref>
<interceptor-ref name="fileUploadStack"></interceptor-ref>
<result name="input">/fileupload/fileUpload.jsp</result>
<result name="success">/fileupload/showUpload.jsp</result>
</action>
</package>
4.web.xml配置
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter>
<filter-name>struts-cleanup</filter-name>
<filter-class>org.apache.struts2.dispatcher.ActionContextCleanUp</filter-class>
</filter>
<filter-mapping>
<filter-name>struts-cleanup</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
5.显示页面：showUpload.jsp
<body>
<img src='UploadImages/<s:property value="imageFileName"/>'/>
<br>
<s:property value="caption"/>
</body>
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
二：多文件上传
Struts 2实现多文件上传也很简单。你可以将多个<s:file />绑定Action的数组或列表。如下例所示。
< s:form action ="doMultipleUploadUsingList" method ="POST" enctype ="multipart/form-data" >
< s:file label ="File (1)" name ="upload" />
< s:file label ="File (2)" name ="upload" />
< s:file label ="FIle (3)" name ="upload" />
< s:submit />
</ s:form >
如果你希望绑定到数组，Action的代码应类似：
private File[] uploads;
private String[] uploadFileNames;
private String[] uploadContentTypes;
public File[] getUpload() { return this .uploads; }
public void setUpload(File[] upload) { this .uploads = upload; }
public String[] getUploadFileName() { return this .uploadFileNames; }
public void setUploadFileName(String[] uploadFileName) { this .uploadFileNames = uploadFileName; }
public String[] getUploadContentType() { return this .uploadContentTypes; }
public void setUploadContentType(String[] uploadContentType) { this .uploadContentTypes = uploadContentType; }
如果你想绑定到列表，则应类似：
private List < File > uploads = new ArrayList < File > ();
private List < String > uploadFileNames = new ArrayList < String > ();
private List < String > uploadContentTypes = new ArrayList < String > ();
public List < File > getUpload() {
return this .uploads;
}
public void setUpload(List < File > uploads) {
this .uploads = uploads;
}
public List < String > getUploadFileName() {
return this .uploadFileNames;
}
public void setUploadFileName(List < String > uploadFileNames) {
this .uploadFileNames = uploadFileNames;
}
public List < String > getUploadContentType() {
return this .uploadContentTypes;
}
public void setUploadContentType(List < String > contentTypes) {
this .uploadContentTypes = contentTypes;
}
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