Detailed explanation of the JXLS framework in the Java class library
The JXLS framework is an open source framework for generating excel files in the Java application.It provides simple and powerful methods to create an excel file with complex format and data.The JXLS framework uses the Apache Poi library for its underlying implementation, which provides the function of operating the Excel file.
The JXLS framework has the following characteristics:
1. Template engine: JXLS uses template -based methods to generate excel files.Users can create an Excel template file and define formats and styles in the template.JXLS can then load data from the database, set or other data sources, and fill the data into the corresponding position in the template.
2. Export function: Use JXLS, you can easily export the data to the Excel file.You can use the API provided by JXLS to export the data as a file or .xlsx format.
3. Dynamic generation: JXLS allows you to dynamically generate excel files at runtime.You can use Java code to create a Workbook object and add data and formatting instructions directly to the workbook.
Below is a simple example. How to use JXLS to generate an Excel file containing employee information:
import org.apache.poi.ss.usermodel.Workbook;
import org.jxls.common.Context;
import org.jxls.util.JxlsHelper;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
public class JXLSExample {
public static void main(String[] args) {
try (InputStream templateStream = JXLSExample.class.getResourceAsStream("/employee_template.xls");
OutputStream outputStream = new FileOutputStream("employee_output.xls")) {
List<Employee> employees = getEmployeeData();
try (Workbook workbook = JxlsHelper.getInstance().createWorkbook(templateStream, outputStream)) {
Context context = new Context();
context.putVar("employees", employees);
JxlsHelper.getInstance().processTemplate(context, workbook);
workbook.write(outputStream);
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
private static List<Employee> getEmployeeData() {
List<Employee> employees = new ArrayList<>();
employees.add(new Employee("John Doe", "Developer", 5000));
employees.add(new Employee("Jane Smith", "Manager", 7000));
employees.add(new Employee("Adam Johnson", "Designer", 4500));
// Add more employees as needed
return employees;
}
private static class Employee {
private String name;
private String role;
private int salary;
public Employee(String name, String role, int salary) {
this.name = name;
this.role = role;
this.salary = salary;
}
public String getName() {
return name;
}
public String getRole() {
return role;
}
public int getSalary() {
return salary;
}
}
}
In the above example, we first load an Excel template file (Employee_template.xls), and then use JXLS to create a Workbook object.Next, we create a Context object and add the employee list to Context.Finally, we use the `ProcessSessterMplate () method to merge the data and the template and write the results into the output stream.
By using the JXLS framework, we can easily generate Excel files containing dynamic data and complex formats.I hope this article will help you understand the principles and usage of the JXLS framework.
