java导出Excel并下载到本地

1、maven添加依赖

	<!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
		<dependency>
			<groupId>org.apache.poi</groupId>
			<artifactId>poi</artifactId>
			<version>4.0.1</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml -->
		<dependency>
			<groupId>org.apache.poi</groupId>
			<artifactId>poi-ooxml</artifactId>
			<version>4.0.1</version>
		</dependency>

2、工具类ExportExcelUtils
用户生成表格

package com.cy.pj.common.util;

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.*;
import org.apache.poi.xssf.usermodel.extensions.XSSFCellBorder;

import com.cy.pj.sys.entity.ExcelData;

import javax.servlet.http.HttpServletResponse;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.List;
 
public class ExportExcelUtils {
 
    /**
     * 下载文件
     * @param response
     * @param fileName
     * @param data
     * @throws Exception
     */
    public static void exportExcel(HttpServletResponse response, String fileName, ExcelData data) throws Exception {
        // 告诉浏览器用什么软件可以打开此文件
        response.setHeader("content-Type", "application/vnd.ms-excel");
        // 下载文件的默认名称
        response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "utf-8"));
        exportExcel(data, response.getOutputStream());
    }
 
    /**
     * 创建 表格
     * @param data
     * @param out
     * @throws Exception
     */
    public static void exportExcel(ExcelData data, OutputStream out) throws Exception {
        XSSFWorkbook wb = new XSSFWorkbook();
        try {
            String sheetName = data.getName();
            if (null == sheetName) {
                sheetName = "Sheet1";
            }
            XSSFSheet sheet = wb.createSheet(sheetName);
            writeExcel(wb, sheet, data);
            wb.write(out);
        } finally {
            wb.close();
        }
    }
 
    /**
     * 将数据写入表格
     * @param wb
     * @param sheet
     * @param data
     */
    private static void writeExcel(XSSFWorkbook wb, Sheet sheet, ExcelData data) {
        int rowIndex = 0;
        rowIndex = writeTitlesToExcel(wb, sheet, data.getTitles());
        writeRowsToExcel(wb, sheet, data.getRows(), rowIndex);
        autoSizeColumns(sheet, data.getTitles().size() + 1);
    }
 
    /**
     * 写入表头
     * @param wb
     * @param sheet
     * @param titles
     * @return
     */
    private static int writeTitlesToExcel(XSSFWorkbook wb, Sheet sheet, List<String> titles) {
        int rowIndex = 0;
        int colIndex = 0;
        Font titleFont = wb.createFont();//获取字体
        titleFont.setFontName("simsun");//设置字体名称(宋体)
        titleFont.setBold(true);//设置字体加粗
        titleFont.setColor(IndexedColors.BLACK.index);//设置字体颜色 黑色
        XSSFCellStyle titleStyle = wb.createCellStyle();//获取单元格样式
        titleStyle.setAlignment(HorizontalAlignment.CENTER);//设置单元格的水平对齐类型(这里是水平居中)
        titleStyle.setVerticalAlignment(VerticalAlignment.CENTER);//设置单元格的垂直对齐类型(这里是居中)
        titleStyle.setFillForegroundColor(createXssfColor("#FFFFFF"));//设置单元格前景色(白色)
        titleStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);//指定图案和纯色单元格填充的单元格填充信息(实心前景)
        titleStyle.setFont(titleFont);//设置字体样式
        setBorder(titleStyle, BorderStyle.THIN, createXssfColor("#000000"));//设置边框样式(细线、黑色)
        Row titleRow = sheet.createRow(rowIndex);//在该工作簿中创建第一行.
        colIndex = 0;
        for (String field : titles) {//循环创建列
            Cell cell = titleRow.createCell(colIndex);
            cell.setCellValue(field);
            cell.setCellStyle(titleStyle);
            colIndex++;
        }
        rowIndex++;//将行数++ 返回用于下面添加数据
        return rowIndex;
    }
 
    /**
     * 将数据写入
     * @param wb
     * @param sheet
     * @param rows
     * @param rowIndex
     * @return
     */
    private static int writeRowsToExcel(XSSFWorkbook wb, Sheet sheet, List<List<Object>> rows, int rowIndex) {
        int colIndex = 0;
        Font dataFont = wb.createFont();//获取字体
        dataFont.setFontName("simsun");//设置字体名称(宋体)
        dataFont.setColor(IndexedColors.BLACK.index);//设置字体颜色 黑色
        XSSFCellStyle dataStyle = wb.createCellStyle();//获取单元格样式
        dataStyle.setAlignment(HorizontalAlignment.CENTER);//设置单元格的水平对齐类型(这里是水平居中)
        dataStyle.setVerticalAlignment(VerticalAlignment.CENTER);//设置单元格的垂直对齐类型(这里是居中)
        dataStyle.setFont(dataFont);//设置字体样式
        setBorder(dataStyle, BorderStyle.THIN, createXssfColor("#000000"));//设置边框样式(细线、黑色)
        for (List<Object> rowData : rows) {//循环写入数据
            Row dataRow = sheet.createRow(rowIndex);
            colIndex = 0;
            for (Object cellData : rowData) {
                Cell cell = dataRow.createCell(colIndex);
                if (cellData != null) {
                    cell.setCellValue(cellData.toString());
                } else {
                    cell.setCellValue("");
                }
 
                cell.setCellStyle(dataStyle);
                colIndex++;
            }
            rowIndex++;
        }
        return rowIndex;
    }
 
    /**
     * 自动调整大小
     * @param sheet
     * @param columnNumber
     */
    private static void autoSizeColumns(Sheet sheet, int columnNumber) {
        for (int i = 0; i < columnNumber; i++) {
            int orgWidth = sheet.getColumnWidth(i);
            sheet.autoSizeColumn(i, true);
            int newWidth = (int) (sheet.getColumnWidth(i) + 100);
            if (newWidth > orgWidth) {
                sheet.setColumnWidth(i, newWidth);
            } else {
                sheet.setColumnWidth(i, orgWidth);
            }
        }
    }
 
    /**
     * 设置表格样式
     * @param style
     * @param border
     * @param color
     */
    private static void setBorder(XSSFCellStyle style, BorderStyle border, XSSFColor color) {
        style.setBorderTop(border);
        style.setBorderLeft(border);
        style.setBorderRight(border);
        style.setBorderBottom(border);
        style.setBorderColor(XSSFCellBorder.BorderSide.TOP, color);
        style.setBorderColor(XSSFCellBorder.BorderSide.LEFT, color);
        style.setBorderColor(XSSFCellBorder.BorderSide.RIGHT, color);
        style.setBorderColor(XSSFCellBorder.BorderSide.BOTTOM, color);
    }
 
    /**
     * 将rgb颜色码 转换为 XSSFColor
     * @param color
     * @return
     */
    private static XSSFColor createXssfColor(String color) {
        int[] rgbColor = hexToRgb(color);
        XSSFColor xssfColor = new XSSFColor(new java.awt.Color(rgbColor[0], rgbColor[1], rgbColor[2]), new DefaultIndexedColorMap());
        return xssfColor;
    }
 
    /**
     * 将颜色码 转换为 r g b
     * @param hex
     * @return
     */
    public static int[] hexToRgb(String hex) {
        String colorStr = hex;
        if (hex.startsWith("#")) {
            colorStr = hex.substring(1);
        }
        if (colorStr.length() == 8) {
            colorStr = hex.substring(2);
        }
        int  r=  Integer.valueOf( colorStr.substring( 0, 2 ), 16 );
        int  g=  Integer.valueOf( colorStr.substring( 2, 4 ), 16 );
        int  b=  Integer.valueOf( colorStr.substring( 4, 6 ), 16 );
 
        return new int[] { r, g, b };
    }
 
}



3、VO类ExcelData
用于封装:表头、单元格数据、sheet表名称
@Data是lombok插件,可以自动生产set和get方法

package com.cy.pj.sys.entity;

import lombok.Data;

import java.io.Serializable;
import java.util.List;
@Data
public class ExcelData implements Serializable {
 
    private static final long serialVersionUID = 4454016249210520899L;
 
    /**
     * 表头
     */
    private List<String> titles;
 
    /**
     * 数据
     */
    private List<List<Object>> rows;
 
    /**
     * 页签名称
     */
    private String name;
 
}

4、测试类

	@RequestMapping("/doExportUserExcel")
	public void doExportUserExcel(HttpServletResponse response) throws Exception {
        ExcelData data = new ExcelData();
        
        data.setName("hello");//sheet表名称
        
        //表头
        List<String> titles = new ArrayList();
        titles.add("姓名");
        titles.add("性别");
        titles.add("年龄");
        titles.add("手机号");
        
        data.setTitles(titles);
        
        List<List<Object>> rows = new ArrayList();
        
        List<Object> row1 = new ArrayList();
        row1.add("张三");
        row1.add("男");
        row1.add("23");
        row1.add("18612341234");
        List<Object> row2 = new ArrayList();
        row2.add("李四");
        row2.add("女");
        row2.add("24");
        row2.add("15312341234");
        
        rows.add(row1);
        rows.add(row2);
        
        data.setRows(rows);
        
        ExportExcelUtils.exportExcel(response,"联系人表.xlsx",data);
		 

//		List userList = sysUserService.findUsers();
//		
//		ExcelData data = new ExcelData();
//		
//        data.setName("用户列表");//sheet名称
//        
//        List titles = new ArrayList();
//        titles.add("编号");
//        titles.add("用户名");
//        titles.add("部门");
//        titles.add("邮箱");
//        titles.add("手机号");
//        titles.add("状态");
//        titles.add("创建时间");
//        titles.add("修改时间");
//        data.setTitles(titles);
//        
//        
//        List> rows = new ArrayList();
//        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
//        for(SysUser sysUser : userList) {
//        	
//        	List row = new ArrayList();
//        	row.add(sysUser.getId());
//        	row.add(sysUser.getUsername());
//        	row.add(sysUser.getDeptId());
//        	row.add(sysUser.getEmail());
//        	row.add(sysUser.getMobile());
//        	row.add(sysUser.getValid());
//        	Date createdTime = sysUser.getCreatedTime();
			//使用SimpleDateFormat 格式化Date需要判断Date不为null
			//如果不进行判断,当Date为null时,会报空指针异常
//        	if(createdTime != null) {
//        		row.add(sdf.format(createdTime));
//        	}else {
//        		row.add("/");
//        	}
//        	
//        	Date modifiedTime = sysUser.getModifiedTime();
//        	if(modifiedTime != null) {
//        		row.add(sdf.format(modifiedTime));
//        	}else {
//        		row.add("/");
//        	}
//        	rows.add(row);
//        }
//        data.setRows(rows);
//        ExportExcelUtils.exportExcel(response,"用户表.xlsx",data);
	}

5、结果
在这里插入图片描述

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