Hibernate export to csv - mysql

Question

I want to export query result to excel or csv file.
I am using hibernate struts.
Is there any query like 'into outfile' which can directly export excel to specified location?
In MySQL database, 'into outfile' query works fine but in hibernate it is not working.
I tried using native sql but it gives error 'couldn't execute bulk manipulation query' and anyhow I can not solve that.
I am using MySQL database.

Answer 1

If you are writing an web app and using spring you can do it by writing data to an output stream
Write a simple class to construct your response
public class CsvResponse {
private final String filename;
private final List<YourPojo> records;
public CsvResponse(List<YourPojo> records, String filename) {
this.records = records;
this.filename = filename;
}
public String getFilename() {
return filename;
}
public List<YourPojo> getRecords() {
return records;
}
}
Now write a message converter to write them to an output stream
public class CsvMessageConverter extends AbstractHttpMessageConverter<CsvResponse> {
public static final MediaType MEDIA_TYPE = new MediaType("text", "csv", Charset.forName("UTF-8"));
public CsvMessageConverter() {
super(MEDIA_TYPE);
}
protected boolean supports(Class<?> clazz) {
return CsvResponse.class.equals(clazz);
}
protected void writeInternal(CsvResponse response, HttpOutputMessage output) throws Exception {
output.getHeaders().setContentType(MEDIA_TYPE);
output.getHeaders().set("Content-Disposition", "attachment; filename=\"" + response.getFilename() + "\"");
OutputStream out = output.getBody();
CsvWriter writer = new CsvWriter(new OutputStreamWriter(out), '\u0009');
List<YourPojo> allRecords = response.getRecords();
for (int i = 1; i < allRecords.size(); i++) {
YourPojo aReq = allRecords.get(i);
writer.write(aReq.toString());
}
writer.close();
}
}
Add this Message converter to your app context config file
<mvc:annotation-driven>
<mvc:message-converters register-defaults="true">
<bean class="com.yourpackage.CsvMessageConverter"/>
</mvc:message-converters>
</mvc:annotation-driven>
Finally the controller will look like
#RequestMapping(value = "/csvData", method = RequestMethod.GET, produces="text/csv")
#ResponseBody
public CsvResponse getFullData(HttpSession session) throws IOException {
// get data
List<YourPojo> allRecords = yourService.getData();
return new CsvResponse(allRecords, "yourData.csv");
}
I've found a similar way using JAX RS here.
But the bottomline is you'll have to use a REST mechanism to get data into the output stream if you want to do it in proper way but if your only target is to get data into a file you can just get your data in a list and then simply write it to a file.