As you probably know, CSV (Comma-Separated Value) files are text files that stores values separated by commas. Usually a CSV file has a header and sets of values that are written one set per line. Each line in the CSV file corresponds to a row in the table. For example let's consider the following CSV content, example.csv:
Name,Age,E-mail Mike,27,[email protected] Susan,29,[email protected] Tom,20,[email protected] Elly,32,[email protected]
In this recipe, we will upload this file to the server and we will extract the data into an ArrayList.
We developed this recipe with NetBeans 6.8, JSF 1.2, and GlassFish v3. The JSF 1.2 classes were obtained from the NetBeans JSF 1.2 bundled library. In addition, we have used Apache MyFaces Tomahawk 1.1.9, which provides support for JSF 1.2. You can download this distribution from http://myfaces.apache.org/tomahawk/index.html. The Apache MyFaces Tomahawk libraries (including necessary dependencies) are in the book code bundle, under the /JSF_libs/Apache Tomahawk—JSF 1.2 folder.
First, you must know that for uploading the CSV file you can use any of the previous recipes presented. We decide to use the upload solution from recipe File upload with Apache MyFaces Tomahawk. The snipped code is shown next:
<h:panelGrid columns="3">
<h:outputLabel for="fileID" value="Choose a file to upload:" />
<t:inputFileUpload id="fileID"
value="#{uploadBean.uploadedFile}"
storage="file"
required="true" />
<h:message showSummary="true" showDetail="false" for="fileID"
style="color: red; text-decoration:overline"/>
<h:panelGroup />
<h:commandButton value="Submit" action="#{uploadBean.submit}" />
<h:message for="uploadForm" infoStyle="color: blue;"
errorStyle="color: red;" />
</h:panelGrid>
Using this solution, you must have access to the uploaded file stream by calling the uploadedFile.getInputStream() method in the UploadBean bean. Before processing this stream, we define a POJO class that maps the name, age, and email fields as shown next:
package uploadpkg;
public class csvObject {
private String name;
private byte age;
private String email;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public byte getAge() {
return age;
}
public void setAge(byte age) {
this.age = age;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
Next, we write the UploadBean bean as shown next:
package uploadpkg;
import org.apache.myfaces.custom.fileupload.UploadedFile;
import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import java.io.InputStream;
import java.io.ByteArrayOutputStream;
import java.util.StringTokenizer;
import java.util.List;
import java.util.ArrayList;
public class UploadBean {
private UploadedFile uploadedFile;
private String fileName;
private List<csvObject> csvs = new ArrayList<csvObject>();
public List<csvObject> getCsvs() {
return csvs;
}
public void setCsvs(List<csvObject> csvs) {
this.csvs = csvs;
}
public UploadedFile getUploadedFile() {
return uploadedFile;
}
public String getFileName() {
return fileName;
}
public void setUploadedFile(UploadedFile uploadedFile) {
this.uploadedFile = uploadedFile;
}
public void submit() {
// Get information you from the uploaded file
System.out.println("Uploaded file name: "
+ uploadedFile.getName());
System.out.println("Uploaded file type: "
+ uploadedFile.getContentType());
System.out.println("Uploaded file size: "
+ uploadedFile.getSize() + " bytes");
try {
//get the uploaded file
InputStream inputStream = uploadedFile.getInputStream();
ByteArrayOutputStream byteArrayOutputStream = new
ByteArrayOutputStream();
//define the byte size
byte bufferZone[] = new byte[1024];
int read = 0;
//read CSV
while( (read = inputStream.read(bufferZone, 0,
(int)uploadedFile.getSize())) != -1 )
{
byteArrayOutputStream.write( bufferZone, 0, read);
}
//assign it to string
String cvs = new String(byteArrayOutputStream.toByteArray());
StringTokenizer stringTokenizer_1 = new
StringTokenizer(cvs,"
");
stringTokenizer_1.nextToken();
while (stringTokenizer_1.hasMoreTokens()){
StringTokenizer stringTokenizer_2 = new
StringTokenizer(stringTokenizer_1.nextToken(),",");
csvObject csvobj = new csvObject();
csvobj.setName(stringTokenizer_2.nextToken());
csvobj.setAge(Byte.valueOf(stringTokenizer_2.nextToken()));
csvobj.setEmail(stringTokenizer_2.nextToken());
csvs.add(csvobj);
}
this.setCsvs(csvs);
//Upload success
FacesContext.getCurrentInstance().addMessage("uploadForm", new FacesMessage(FacesMessage.SEVERITY_INFO, "File upload was a total success!", null));
} catch (Exception e) {
//Upload failed
FacesContext.getCurrentInstance().addMessage("uploadForm", new
FacesMessage(FacesMessage.SEVERITY_ERROR, "File upload was a
failed.", null));
e.printStackTrace();
}
}
}
The uploaded file InputStream, passes through these steps:
- First, we assign an
InputStreamobject to theuploadedFile.getInputStream()method. - The stream content is transferred into a
ByteArrayOutputStreamobject. - We convert the
ByteArrayOutputStreaminto aString. - We use a
StringTokenizer, to get each row from thisString. For this we use the" "as separator. - We apply another
StringTokenizerto get values from each row returned by the previousStringTokenizer. Now, the separator is",". - We populate an instance of the
csvObjectPOJO with the extracted values. - We add each instance into an
ArrayList<csvObject>.