JXLS2实现创建组折叠

通过JXLS2实现如下折叠的表格的导出。

如一个Lead下面管理了多个人员，将下属人员折叠起来，点击后展开下属的人员列表。


在官方自带的文档中自带了实现分组折叠的DEMO，我们在这基础上稍作改动即可实现以上的分组折叠效果。

Maven引入JXLS

<dependency>
	<groupId>org.jxlsgroupId>
	<artifactId>jxlsartifactId>
	<version>2.6.0version>
dependency>
<dependency>
	<groupId>org.jxlsgroupId>
	<artifactId>jxls-poiartifactId>
	<version>1.2.0version>
dependency>

分组折叠命令代码

以下代码来自于官方jxls-examples的demo模块下，创建了一个新的jxls命令：groupRow。

import org.jxls.area.Area;
import org.jxls.command.AbstractCommand;
import org.jxls.command.Command;
import org.jxls.common.CellRef;
import org.jxls.common.Context;
import org.jxls.common.Size;
import org.jxls.transform.poi.PoiTransformer;
import org.jxls.util.Util;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;


public class GroupRowCommand extends AbstractCommand {
    Area area;
    String collapseIf;

    public String getName() {
        return "groupRow";
    }

    public Size applyAt(CellRef cellRef, Context context) {
        Size resultSize = area.applyAt(cellRef, context);
        if( resultSize.equals(Size.ZERO_SIZE)) return resultSize;
        PoiTransformer transformer = (PoiTransformer) area.getTransformer();
        Workbook workbook = transformer.getWorkbook();
        Sheet sheet = workbook.getSheet(cellRef.getSheetName());
        int startRow = cellRef.getRow();
        int endRow = cellRef.getRow() + resultSize.getHeight() - 1;
        sheet.groupRow(startRow, endRow);
        if( collapseIf != null && collapseIf.trim().length() > 0){
            boolean collapseFlag = Util.isConditionTrue(getTransformationConfig().getExpressionEvaluator(), collapseIf, context);
            sheet.setRowGroupCollapsed(startRow, collapseFlag);
        }
        return resultSize;
    }

    @Override
    public Command addArea(Area area) {
        super.addArea(area);
        this.area = area;
        return this;
    }

    public void setCollapseIf(String collapseIf) {
        this.collapseIf = collapseIf;
    }
}

JXLS参考：
JXLS官网
JXLS的API.

创建JXLS模板

以下举个简单的例子：

1. 输出对象定义

public class Employee {
    private String name;
    private int age;
    private Double payment;
    private Double bonus;
    private Date birthDate;
    private List<Employee> employees;
    /**此处省略构造函数及get和set方法**/
}

2. JXLS模板
   第一行通过jx:each循环获取Employee
   第二行通过自定义的jx:groupRow实现分组，通过collapseIf=“employee.employees.size()>0” 判断折叠的条件，然后循环Employee下的List employees，获取子集。
   

导出EXCEL

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;

import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.jxls.area.Area;
import org.jxls.builder.AreaBuilder;
import org.jxls.builder.xls.XlsCommentAreaBuilder;
import org.jxls.common.CellRef;
import org.jxls.common.Context;
import org.jxls.demo.model.Employee;
import org.jxls.transform.Transformer;
import org.jxls.util.TransformerFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class UserCommandExcelMarkupDemo {

	static Logger logger = LoggerFactory.getLogger(UserCommandExcelMarkupDemo.class);

	private static String template = "user_command_markup_template.xls";

	private static String output = "target/user_command_markup_output.xls";

	public static void main(String[] args) throws IOException, InvalidFormatException, ParseException {
		logger.info("Running User Command Markup demo");
		execute();
	}

	public static void execute() throws IOException, InvalidFormatException, ParseException {
		List<Employee> employees = generateSampleEmployeeData();
		logger.info("Opening input stream");
		try (InputStream is = UserCommandExcelMarkupDemo.class.getResourceAsStream(template)) {
			try (OutputStream os = new FileOutputStream(output)) {
				Transformer transformer = TransformerFactory.createTransformer(is, os);
				AreaBuilder areaBuilder = new XlsCommentAreaBuilder(transformer);
				/**添加自定义命令**/	
				XlsCommentAreaBuilder.addCommandMapping("groupRow", GroupRowCommand.class);
				List<Area> xlsAreaList = areaBuilder.build();
				Area xlsArea = xlsAreaList.get(0);
				Context context = new Context();
				context.putVar("employees", employees);
				xlsArea.applyAt(new CellRef("Result!A1"), context);
				transformer.write();
				logger.info("Finished UserCommandExcelMarkupDemo");
			}
		}
	}

	private static List<Employee> generateSampleEmployeeData() throws ParseException {
		List<Employee> employees = new ArrayList<>();
		List<Employee> employees2 = new ArrayList<>();
		List<Employee> leadEmployees = new ArrayList<>();
		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MMM-dd", Locale.US);
		employees.add(new Employee("Elsa", dateFormat.parse("1970-Jul-10"), 1500d, 0.15));
		employees.add(new Employee("Oleg", dateFormat.parse("1973-Apr-30"), 2300d, 0.25));
		employees.add(new Employee("Neil", dateFormat.parse("1975-Oct-05"), 2500d, 0.00));
		employees.add(new Employee("Maria", dateFormat.parse("1978-Jan-07"), 1700d, 0.15));
		employees.add(new Employee("John", dateFormat.parse("1969-May-30"), 2800d, 0.20));

		employees2.add(new Employee("Elsa1", dateFormat.parse("1970-Jul-10"), 1500d, 0.15));
		employees2.add(new Employee("Oleg1", dateFormat.parse("1973-Apr-30"), 2300d, 0.25));
		employees2.add(new Employee("Neil1", dateFormat.parse("1975-Oct-05"), 2500d, 0.00));

		leadEmployees.add(new Employee("Lead1", dateFormat.parse("1969-May-30"), 12800d, 0.50, employees));
		leadEmployees.add(new Employee("Lead2", dateFormat.parse("1979-May-30"), 22800d, 0.50, employees2));
		return leadEmployees;
	}
}

以上就能实现文章开头展示的情况。