Implement code to upload multiple files at the same time in struts2

Author：Eve Cole Update Time：2024-11-19 16:36:01

Name multiple file field objects with the same name in the upload.jsp page, so that multiple file fields can be parsed into an array in the action. The size of the array is the number of file fields. At the same time, one file field is parsed into Three corresponding variables, so multiple file fields correspond to three arrays, where the size of each array is the number of file fields. The jsp page code is as follows:

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<form action="upload.action" name="uploadForm" method="post" enctype="multipart/form-data">
File title: <input type="text" name="title"/><br/>
Select file -:<input type="file" name="upload"/><br/>
Select file two: <input type="file" name="upload"/><br/>
Select file three: <input type="file" name="upload"/><br/>
<input type="submit" value="upload"/>

</form>

The corresponding Action traverses all file fields in sequence, and then generates the corresponding input file stream. The output file stream adds the corresponding output file stream to save the file in the specified server storage path. At the same time, dynamically specify the saving path of the file on the server.

The action code is as follows:

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package com.inspur.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 UploadAction extends ActionSupport {
private String title;
private File[] upload;
private String[] uploadFileName;
private String[] uploadContentType;
private String savePath;

public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public File[] getUpload() {
return upload;
}
public void setUpload(File[] upload) {
this.upload = upload;
}
public String[] getUploadFileName() {
return uploadFileName;
}
public void setUploadFileName(String[] uploadFileName) {
this.uploadFileName = uploadFileName;
}
public String[] getUploadContentType() {
return uploadContentType;
}
public void setUploadContentType(String[] uploadContentType) {
this.uploadContentType = uploadContentType;
}
public String getSavePath() {
return ServletActionContext.getRequest().getRealPath(savePath);
}
public void setSavePath(String savePath) {
this.savePath = savePath;
}
public String upload()throws Exception{
File[] files=this.getUpload();
for(int i=0;i<files.length;i++){
FileOutputStream fos=new FileOutputStream(this.getSavePath()+"//"+this.getUploadFileName()[i]);
byte[] buffer=new byte[1024];
FileInputStream fis=new FileInputStream(files[i]);
int len=0;
while((len=fis.read(buffer))>0){
fos.write(buffer,0,len);
}
}

return SUCCESS;
}

}

The struts.xml file is configured as follows: configure the interceptor for file upload, allowed upload file types, upload file size limit, and introduce the defaultStack interceptor and the storage location of the uploaded file on the server.

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<struts>
<constant name="struts.custom.i18n.resources" value="message"></constant>
<constant name="struts.i18n.encoding" value="gbk"></constant>
<package name="uploadMult" extends="struts-default" namespace="/">
<action name="upload" method="upload">
<interceptor-ref name="fileUpload">
<param name="allowedTypes">image/bmp,image/png,image/gif,image/jpeg</param>
<param name="maximumSize">20000000000</param>
</interceptor-ref>
<interceptor-ref name="defaultStack"></interceptor-ref>
<param name="savePath">/upload</param>
<result name="success">/success.jsp</result>
<result name="input">/upload.jsp</result>
<result name="error">/error.jsp</result>
</action>
</package>

</struts>

The web.xml file code is as follows: The struts-cleanup filter is configured, which has no direct impact on the file upload function. However, as an auxiliary class for the struts core filter, the system is more stable and unknown exceptions are eliminated.

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<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>

Display all uploaded images on the upload success interface:

The success.jsp page code is as follows:

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File title: <s:property value="title"/><br/>
The first image: <img src="<s:property value="'upload/'+uploadFileName[0]"/>"/><br/>
The second image: <img src="<s:property value="'upload/'+uploadFileName[1]"/>"/><br/>

Strus2 also supports using lists to upload multiple files at the same time. The principle is the same as that of arrays, and there is no fundamental difference. It's just about changing all arrays into lists. And by modifying the access method of the list, you can use the list to encapsulate the file domain parameters. Achieve simultaneous upload of multiple files.