Struts2 Study Notes (11)-file upload and struts2 Study Notes
1. Upload a single file
Steps for uploading a single file:
1) Create an upload jsp page
The file upload form must be submitted in POST mode. The encoding type is enctype = "multipart/form-data". The default format is application/x-www-form-urlencoded. For example:
1 <form action="${pageContext.servletContext.contextPath}/uploadAction.action" enctype="multipart/form-data" method="post">
2) create an Action class for processing file uploads
3) configure the struts. xml file
1 <constant name="struts.multipart.maxSize" value="20000000"></constant>
Sets the total size of the uploaded file, which is valid for all uploaded forms. You only want to set the current form. You can set the fileUpload interceptor attribute.
You can configure these attributes in the struts. xml file:
1 <interceptor-ref name = "defaultStack"> 2 <! -- Configure the size of the uploaded file. Here, the size of the uploaded file is configured. --> 3 <param name = "fileUpload. maximumSize"> 20971520 </param> 4 <! -- Configure the types allowed for the upload file --> 5 <param name = "fileUpload. allowedTypes"> text/plain, application/msword </param> 6 <! -- Configure the File Upload extension --> 7 <param name = "fileUpload. allowedExtensions"> .txt,.doc </param> 8 </interceptor-ref>
The allowed types (allowedTypes) and allowed extensions (allowedExtensions) must be consistent.
Example of uploading a single file:
1) create a jsp page
1 <body> 2 <form action = "$ {pageContext. servletContext. contextPath}/uploadAction. action "enctype =" multipart/form-data "method =" post "> 3. upload a file: <input type = "file" name = "upload"> 4 <input type = "submit" value = "upload"> 5 </form> 6 </body>
2) create an Action class
1 public class UploadAction extends ActionSupport {2 private File upload; 3 private String uploadContentType; 4 private String uploadFileName; 5 6 public File getUpload () {7 return upload; 8} 9 10 public void setUpload (File upload) {11 this. upload = upload; 12} 13 14 public String getUploadContentType () {15 return uploadContentType; 16} 17 18 public void setUploadContentType (String uploadContentType) {19 this. uploadContentType = uploadContentType; 20} 21 22 public String getUploadFileName () {23 return uploadFileName; 24} 25 26 public void setUploadFileName (String uploadFileName) {27 this. uploadFileName = uploadFileName; 28} 29 30 @ Override31 public String execute () throws Exception {32 ServletContext SC = ServletActionContext. getServletContext (); 33 // get the location of the file to be saved 34 String path = SC. getRealPath ("/upload"); 35 // create a File 36 file File = new File (path, uploadFileName) with the same name as the uploaded file ); 37 // copy the temporary file content to the file named 38 FileUtils in the target folder. copyFile (upload, file); 39 // Delete the temporary file 40 upload. delete (); 41 return SUCCESS; 42} 43}
3) configure the struts. xml file
1 <struts> 2 <constant name="struts.devMode" value="true" /> 3 <constant name="struts.multipart.maxSize" value="200000000"/> 4 <package name="default" namespace="/" extends="struts-default"> 5 <action name="uploadAction" class="com.sunny.action.UploadAction"> 6 <result>/success.jsp</result> 7 <result name="input">/error.jsp</result> 8 <interceptor-ref name="defaultStack"> 9 <param name="fileUpload.maximumSize">20971520</param>10 <param name="fileUpload.allowedTypes">text/plain,application/msword</param>11 <param name="fileUpload.allowedExtensions">.txt,.doc</param>12 </interceptor-ref>13 </action>14 </package>15 </struts>
4) file upload interface
5) after the upload is successful, the success. jsp page is displayed.
6) There will be uploaded files in the project's upload folder.
Upload question information Internationalization
Struts2 uploads question information the default file is under the struts-message.properties:
1 struts.messages.error.uploading=Error uploading: {0}2 struts.messages.error.file.too.large=File too large: {0} "{1}" "{2}" {3}3 struts.messages.error.content.type.not.allowed=Content-Type not allowed: {0} "{1}" "{2}" {3}4 struts.messages.error.file.extension.not.allowed=File extension not allowed: {0} "{1}" "{2}" {3}
To display Chinese characters, you must create the ActionClassName. properties file under the same file of the Action class. The ActionClassName file is the class name of the upload Action class, and change the file content:
1 struts. messages. error. uploading = upload error: {0} 2 struts. messages. error. file. too. large = the file to be uploaded is too large: {0} "{1}" "{2}" {3} 3 struts. messages. error. content. type. not. allowed = the File Upload type is not allowed: {0} "{1}" "{2}" {3} 4 struts. messages. error. file. extension. not. allowed = the extension of the uploaded file is not allowed: {0} "{1}" "{2}" {3}
The content before the equal sign is fixed, and the content after it can be written by yourself.
2. Multifile upload
The process for uploading multiple files is the same as that for uploading a single file, but note that:
Example of uploading a single file:
1) create a jsp page
1 <body> 2 <form action = "$ {pageContext. servletContext. contextPath}/uploadAction. action "enctype =" multipart/form-data "method =" post "> 3. upload a file: <input type = "file" name = "upload"> <br> 4. upload a file: <input type = "file" name = "upload"> <br> 5. upload a file: <input type = "file" name = "upload"> <br> 6. upload a file: <input type = "file" name = "upload"> <br> 7 <input type = "submit" value = "upload"> 8 </form> 9 </body>
2) create an Action class
1 public class UploadAction extends ActionSupport {2 private File [] upload; 3 private String [] uploadContentType; 4 private String [] uploadFileName; 5 6 public File [] getUpload () {7 return upload; 8} 9 10 public void setUpload (File [] upload) {11 this. upload = upload; 12} 13 14 public String [] getUploadContentType () {15 return uploadContentType; 16} 17 18 public void setUploadContentType (String [] uploadContentType) {19 this. uploadContentType = uploadContentType; 20} 21 22 public String [] getUploadFileName () {23 return uploadFileName; 24} 25 26 public void setUploadFileName (String [] uploadFileName) {27 this. uploadFileName = uploadFileName; 28} 29 30 @ Override31 public String execute () throws Exception {32 ServletContext SC = ServletActionContext. getServletContext (); 33 // get the location of the file to be saved 34 String path = SC. getRealPath ("/upload"); 35 // create a file 36 for (int I = 0; I <upload. length; I ++) {37 File file = new File (path, uploadFileName [I]); 38 // copy the temporary file content to the 39 FileUtils file with the same name in the target folder. copyFile (upload [I], file); 40 // Delete the temporary file 41 upload [I]. delete (); 42} 43 return SUCCESS; 44} 45}
3) configure the struts. xml file, which is the same as the configuration for uploading a single file.
1 <struts> 2 <constant name="struts.devMode" value="true" /> 3 <constant name="struts.multipart.maxSize" value="200000000"/> 4 <package name="default" namespace="/" extends="struts-default"> 5 <action name="uploadAction" class="com.sunny.action.UploadAction"> 6 <result>/success.jsp</result> 7 <result name="input">/error.jsp</result> 8 <interceptor-ref name="defaultStack"> 9 <param name="fileUpload.maximumSize">20971520</param>10 <param name="fileUpload.allowedTypes">text/plain,application/msword</param>11 <param name="fileUpload.allowedExtensions">.txt,.doc</param>12 </interceptor-ref>13 </action>14 </package>15 </struts>
4) file upload interface
5) after the upload is successful, the success. jsp page is displayed.
6) There will be uploaded files in the project's upload folder.
3. File Download
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