POI导出工具类(反射实现)

一时失言乱红尘 2022-04-15 06:27 224阅读 0赞

POI导出工具类  
将前段时间工作中利用POI实现Excel导出的功能代码在此做以下总结:

1.导出工具类

import java.io.BufferedInputStream;  
import java.io.BufferedOutputStream;  
import java.io.ByteArrayInputStream;  
import java.io.ByteArrayOutputStream;  
import java.io.IOException;  
import java.io.InputStream;  
import java.lang.reflect.Method;  
import java.util.ArrayList;  
import java.util.HashMap;  
import java.util.List;  
import java.util.Map;

import javax.servlet.ServletOutputStream;  
import javax.servlet.http.HttpServletResponse;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;  
import org.apache.poi.ss.usermodel.Cell;  
import org.apache.poi.ss.usermodel.CellStyle;  
import org.apache.poi.ss.usermodel.Font;  
import org.apache.poi.ss.usermodel.IndexedColors;  
import org.apache.poi.ss.usermodel.Row;  
import org.apache.poi.ss.usermodel.Sheet;  
import org.apache.poi.ss.usermodel.Workbook;

import com.gcx\_pm.model.ScientificResearch;  
/\*\*

*  @author shilei
 *  @version 创建时间：2017年12月28日 下午4:53:29
 *  类说明: POI导出工具类  
    \*/  
    public class ExportPOIUtils \{
    
    //参数说明: fileName：文件名 projects：对象集合 columnNames： 列名 keys： map中的key  
    public static void start\_download(HttpServletResponse response, String fileName, List<?> projects,  
    String\[\] columnNames, String\[\] keys) throws IOException \{
    
        //将集合中对象的属性  对应到  List<Map<String,Object>>
         List<Map<String,Object>> list=createExcelRecord(projects, keys);
        
         ByteArrayOutputStream os = new ByteArrayOutputStream();
         try {
         	//将转换成的Workbook对象通过流形式下载
         	createWorkBook(list,keys,columnNames).write(os);
         } catch (IOException e) {
         	e.printStackTrace();
         }
         byte[] content = os.toByteArray();
         InputStream is = new ByteArrayInputStream(content);
         // 设置response参数，可以打开下载页面
         response.reset();
         response.setContentType("application/vnd.ms-excel;charset=utf-8");
         response.setHeader("Content-Disposition", "attachment;filename="+ new String((fileName + ".xls").getBytes(), "iso-8859-1"));
         ServletOutputStream out = response.getOutputStream();
         BufferedInputStream bis = null;
         BufferedOutputStream bos = null;
         try {
         	bis = new BufferedInputStream(is);
         	bos = new BufferedOutputStream(out);
         	byte[] buff = new byte[2048];
         	int bytesRead;
         	while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
         		bos.write(buff, 0, bytesRead);
         	}
         } catch (final IOException e) {
         	throw e;
         } finally {
         	if (bis != null)
         		bis.close();
         	if (bos != null)
         		bos.close();
         }
    
    \}
    
    private static List<Map<String, Object>> createExcelRecord(List<?> projects, String\[\] keys) \{  
    List<Map<String, Object>> listmap = new ArrayList<Map<String, Object>>();  
    Map<String, Object> map = new HashMap<String, Object>();  
    map.put(“sheetName”, “sheet”);  
    listmap.add(map);  
    Object project=null;  
    for (int j = 0; j < projects.size(); j++) \{  
    project=projects.get(j);  
    Map<String, Object> mapValue = new HashMap<String, Object>();  
    for(int i=0; i<keys.length; i++)\{  
    mapValue.put(keys\[i\], getFieldValueByName(keys\[i\], project));  
    \}
    
        listmap.add(mapValue);
         }
         return listmap;
    
    \}  
    /\*\*
    
     *  利用反射 根据属性名获取属性值
     *  */  
        private static Object getFieldValueByName(String fieldName, Object o) \{  
        try \{  
        String firstLetter = fieldName.substring(0, 1).toUpperCase();  
        String getter = “get” + firstLetter + fieldName.substring(1);  
        Method method = o.getClass().getMethod(getter, new Class\[\] \{\});  
        Object value = method.invoke(o, new Object\[\] \{\});  
        return value;  
        \} catch (Exception e) \{  
        e.printStackTrace();  
        return null;  
        \}  
        \}  
        /*\*
     *  创建excel文档对象
     *  @param keys list中map的key数组集合
     *  @param columnNames excel的列名
     *  \*/  
        private static Workbook createWorkBook(List<Map<String, Object>> list,String \[\]keys,String columnNames\[\]) \{  
        // 创建excel工作簿  
        Workbook wb = new HSSFWorkbook();  
        // 创建第一个sheet（页），并命名  
        Sheet sheet = wb.createSheet(list.get(0).get(“sheetName”).toString());  
        // 手动设置列宽。第一个参数表示要为第几列设；，第二个参数表示列的宽度，n为列高的像素数。  
        for(int i=0;i<keys.length;i++)\{  
        sheet.setColumnWidth((short) i, (short) (35.7 \* 150));  
        \}
        
        // 创建第一行  
        Row row = sheet.createRow((short) 0);
        
        // 创建两种单元格格式  
        CellStyle cs = wb.createCellStyle();  
        CellStyle cs2 = wb.createCellStyle();
        
        // 创建两种字体  
        Font f = wb.createFont();  
        Font f2 = wb.createFont();
        
        // 创建第一种字体样式（用于列名）  
        f.setFontHeightInPoints((short) 10);  
        f.setColor(IndexedColors.BLACK.getIndex());  
        f.setBoldweight(Font.BOLDWEIGHT\_BOLD);
        
        // 创建第二种字体样式（用于值）  
        f2.setFontHeightInPoints((short) 10);  
        f2.setColor(IndexedColors.BLACK.getIndex());
        
        // 设置第一种单元格的样式（用于列名）  
        cs.setFont(f);  
        cs.setBorderLeft(CellStyle.BORDER\_THIN);  
        cs.setBorderRight(CellStyle.BORDER\_THIN);  
        cs.setBorderTop(CellStyle.BORDER\_THIN);  
        cs.setBorderBottom(CellStyle.BORDER\_THIN);  
        cs.setAlignment(CellStyle.ALIGN\_CENTER);
        
        // 设置第二种单元格的样式（用于值）  
        cs2.setFont(f2);  
        cs2.setBorderLeft(CellStyle.BORDER\_THIN);  
        cs2.setBorderRight(CellStyle.BORDER\_THIN);  
        cs2.setBorderTop(CellStyle.BORDER\_THIN);  
        cs2.setBorderBottom(CellStyle.BORDER\_THIN);  
        cs2.setAlignment(CellStyle.ALIGN\_CENTER);  
        //设置列名  
        for(int i=0;i<columnNames.length;i++)\{  
        Cell cell = row.createCell(i);  
        cell.setCellValue(columnNames\[i\]);  
        cell.setCellStyle(cs);  
        \}  
        //设置每行每列的值  
        for (short i = 1; i < list.size(); i++) \{  
        // Row 行,Cell 方格 , Row 和 Cell 都是从0开始计数的  
        // 创建一行，在页sheet上  
        Row row1 = sheet.createRow((short) i);  
        // 在row行上创建一个方格  
        for(short j=0;j<keys.length;j++)\{  
        Cell cell = row1.createCell(j);  
        cell.setCellValue(list.get(i).get(keys\[j\]) == null?" ": list.get(i).get(keys\[j\]).toString());  
        cell.setCellStyle(cs2);  
        \}  
        \}  
        return wb;  
        \}

\}  
2.Controller接收

@RequestMapping(“exportList”)  
public void exportList(HttpServletResponse response, String ids) \{

String fileName = “人员档案列表”;

List users = sRPService.exportList(ids);

## // 列名   String columnNames\[\] = \{ “ID”, “姓名”, “性别”, “所属部门”, “所属单位”, “邮箱”,   “电话”, “手机”, “学历/学位”, “专业/专科方向”, “直属上级”, “账号锁定” \};   // map中的key   String keys\[\] = \{ “id”, “userName”, “gender”, “dept”, “unit”, “email”,   “tel”, “phone”, “degree”, “major”, “parentName”, “isLocked” \};   try \{   ExportPOIUtils.start\_download(response, fileName, users,columnNames, keys);   \} catch (IOException e) \{   e.printStackTrace();   \}   \}   3. JS   //必须使用location.href   location.href = basePath+"/sRPController/exportList.do?ids="+ids; ##

作者：看得见的等候  
来源：CSDN  
原文：[https://blog.csdn.net/qq\_39028580/article/details/78928219][https_blog.csdn.net_qq_39028580_article_details_78928219]  
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[https_blog.csdn.net_qq_39028580_article_details_78928219]: https://blog.csdn.net/qq_39028580/article/details/78928219