Java使用POI操作Excel,判断标志列如果相同,则合并多组单元格

合并单元格的方法：
指定 4 个参数，起始行，结束行，起始列，结束列。然后这个区域将被合并。

每种材料有四个属性：

• displayCode  代号
• practName    名称
• areaName     地区
• price              价格

需求：根据“displayCode ”判断是否是同一种材料，如果是同一种材料，则合并"displayCode"和"practName "，因为材料所在地和价格各地区都有不同，不合并

代码

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellType;
import org.apache.poi.ss.usermodel.Font;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.VerticalAlignment;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;

public class TestExcel {

    public static void main(String[] args) throws IOException {
        //构建测试数据
		List<Map<String, String>> searchDataList = new ArrayList<>();
		Map<String, String> myMap = new HashMap<>();
		myMap.put("displayCode", "1001001");
		myMap.put("practName", "砂石");
		myMap.put("areaName", "湖南");
		myMap.put("price", "19");
		searchDataList.add(myMap);
		myMap = new HashMap<>();
		myMap.put("displayCode", "1001001");
		myMap.put("practName", "砂石");
		myMap.put("areaName", "河北");
		myMap.put("price", "20");
		searchDataList.add(myMap);
		myMap = new HashMap<>();
		myMap.put("displayCode", "1001002");
		myMap.put("practName", "水泥");
		myMap.put("areaName", "江苏");
		myMap.put("price", "21");
		searchDataList.add(myMap);
		myMap = new HashMap<>();
		myMap.put("displayCode", "1001003");
		myMap.put("practName", "混凝土");
		myMap.put("areaName", "北京");
		myMap.put("price", "22");
		searchDataList.add(myMap);
		myMap = new HashMap<>();
		myMap.put("displayCode", "1001004");
		myMap.put("practName", "砂砾");
		myMap.put("areaName", "四川");
		myMap.put("price", "23");
		searchDataList.add(myMap);
		myMap = new HashMap<>();
		myMap.put("displayCode", "1001004");
		myMap.put("practName", "砂砾");
		myMap.put("areaName", "内蒙古");
		myMap.put("price", "24");
		searchDataList.add(myMap);
		SXSSFWorkbook wb=new SXSSFWorkbook(500);
			
		//标题格式
		XSSFCellStyle ztStyle0 = (XSSFCellStyle) wb.createCellStyle(); 
		 
       // 创建单元格样式对象   
       XSSFCellStyle ztStyle = (XSSFCellStyle) wb.createCellStyle();   
       Font ztFont = wb.createFont();   
       ztFont.setFontHeightInPoints((short)9);    // 将字体大小设置为18px   
       ztFont.setFontName("宋体");  
       ztStyle.setFont(ztFont);                    // 将字体应用到样式上面   

       // 设置单元格内容水平对其方式   
       ztStyle.setAlignment(HorizontalAlignment.CENTER);   
       // 设置单元格内容垂直对其方式   
       ztStyle.setVerticalAlignment(VerticalAlignment.CENTER); 
       ztStyle.setVerticalAlignment(VerticalAlignment.CENTER);   
       ztStyle.setWrapText(true);                     // 设置单元格内容是否自动换行   
       
       // 创建单元格样式对象   
       XSSFCellStyle ztStyle2 = (XSSFCellStyle) wb.createCellStyle();   
       ztStyle2.setFont(ztFont);                    // 将字体应用到样式上面   

       // 设置单元格内容水平对其方式   
       ztStyle2.setAlignment(HorizontalAlignment.LEFT);   
       // 设置单元格内容垂直对其方式   
       ztStyle2.setVerticalAlignment(VerticalAlignment.CENTER); 
       ztStyle2.setVerticalAlignment(VerticalAlignment.CENTER);   
       ztStyle2.setWrapText(true); // 设置单元格内容是否自动换行   
       
	    Sheet sheet=wb.createSheet("合并测试");
		Row row=sheet.createRow(0);
		Cell cell=row.createCell(0, CellType.STRING);
		cell.setCellValue("代号");
		sheet.setColumnWidth(0, 3000);
		cell.setCellStyle(ztStyle);
		cell = row.createCell(1, CellType.STRING);
		cell.setCellValue("名称");
		sheet.setColumnWidth(1, 5000);
		cell.setCellStyle(ztStyle);
		cell = row.createCell(2, CellType.STRING);
		cell.setCellValue("所在地");
		sheet.setColumnWidth(2, 10000);
		cell.setCellStyle(ztStyle);
		cell = row.createCell(3, CellType.STRING);
		cell.setCellValue("单价");
		sheet.setColumnWidth(3, 3000);
		cell.setCellStyle(ztStyle);
		
		if(searchDataList != null && searchDataList.size() > 0 )  {
			int n = 1 ;
			Map<Map<String, String>,Row> rowMap = new LinkedHashMap<>();
			//{0=代号, 1=材料名称, 2=所在地, 4=单价}
			Map<String, String> map = null;
            //key为displayCode,value为displayCode相同的个数有多少个
			Map<String,Integer> sameCountMap = new HashMap<>();
            //key为displayCode,value为第一个代号为该displayCode的初始的行的索引号
			Map<String,Integer> startDisplayCodeMap = new HashMap<>();
			Integer count = null;
			String prevDisplayCode = null;
			String displayCode = null;
			Integer startRowIndex = null;
			for(int i = 0 ; i < searchDataList.size() ; i ++ ) {
				
				map = searchDataList.get(i);
				displayCode = map.get("displayCode");
				map = searchDataList.get(i);
				//代号
				row=sheet.createRow(n); 
				cell = row.createCell(0, CellType.STRING);
				cell.setCellValue(displayCode);
				cell.setCellStyle(ztStyle);
				//材料名称
				cell = row.createCell(1, CellType.STRING);
				cell.setCellValue(map.get("practName"));
				cell.setCellStyle(ztStyle2);
				//所在地
				cell = row.createCell(2, CellType.STRING);
				cell.setCellValue(map.get("areaName"));
				cell.setCellStyle(ztStyle2);
				//单价
				cell = row.createCell(3, CellType.STRING);
				cell.setCellValue(map.get("price"));
				cell.setCellStyle(ztStyle);
				rowMap.put(map, row);
				
				//合并行
				count = sameCountMap.get(displayCode);
				if(count == null) {
					count = 0;
					startDisplayCodeMap.put(displayCode, n);
				}
				count++;
				sameCountMap.put(displayCode, count);
				if(prevDisplayCode != null && !prevDisplayCode.equals(displayCode)) {
					startRowIndex = startDisplayCodeMap.get(prevDisplayCode);//获取该代号的初始行位置
					count = sameCountMap.get(prevDisplayCode);//获取相同代号总共有多少行
					if(count > 1) {
						sheet.addMergedRegion(new CellRangeAddress(startRowIndex, startRowIndex+count-1, 0, 0));//合并代号行
						sheet.addMergedRegion(new CellRangeAddress(startRowIndex, startRowIndex+count-1, 1, 1));//合并工料机名称行
					}
				}else if(i == searchDataList.size() - 1){
					//最后一行
					startRowIndex = startDisplayCodeMap.get(displayCode);//获取该代号的初始行位置
					count = sameCountMap.get(displayCode);//获取相同代号总共有多少行
					if(count > 1) {
						sheet.addMergedRegion(new CellRangeAddress(startRowIndex, startRowIndex+count-1, 0, 0));//合并代号行
						sheet.addMergedRegion(new CellRangeAddress(startRowIndex, startRowIndex+count-1, 1, 1));//合并名称行
					}
				}
				prevDisplayCode = displayCode;
				n++;
			}
		}
        File file = new File("E:\\demo.xlsx");
        FileOutputStream fout = new FileOutputStream(file);
        wb.write(fout);
        fout.close();
    }

}

效果图