Java导出Excel快速开始

Posted 2020-12-17 苦行僧DH

代码：

 package com.scoremanager.utils;
 
 import org.apache.poi.hssf.usermodel.*;
 
 import javax.servlet.http.HttpServletResponse;
 import java.io.BufferedOutputStream;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.util.Collection;
 import java.util.Iterator;
 
 /*
  * 导出Excel的工具类
  * */
 public class ExportExcelUtils<T> {
     public void exportExcel(String[] headers, Collection<T> dataset, String fileName, HttpServletResponse response) {
         // 声明一个工作薄
         HSSFWorkbook workbook = new HSSFWorkbook();
         // 生成一个表格
         HSSFSheet sheet = workbook.createSheet(fileName);
         // 设置表格默认列宽度为15个字节
         sheet.setDefaultColumnWidth((short) 20);
         // 产生表格标题行
         HSSFRow row = sheet.createRow(0);
         for (short i = 0; i < headers.length; i++) {
             HSSFCell cell = row.createCell(i);
             HSSFRichTextString text = new HSSFRichTextString(headers[i]);
             cell.setCellValue(text);
         }
         try {
             // 遍历集合数据，产生数据行
             Iterator<T> it = dataset.iterator();
             int index = 0;
             while (it.hasNext()) {
                 index++;
                 row = sheet.createRow(index);
                 T t = (T) it.next();
                 // 利用反射，根据javabean属性的先后顺序，动态调用getXxx()方法得到属性值
                 Field[] fields = t.getClass().getDeclaredFields();
                 for (short i = 0; i < headers.length; i++) {
                     HSSFCell cell = row.createCell(i);
                     Field field = fields[i];
                     String fieldName = field.getName();
                     String getMethodName = "get" + fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1);
                     Class tCls = t.getClass();
                     Method getMethod = tCls.getMethod(getMethodName, new Class[]{});
                     Object value = getMethod.invoke(t, new Object[]{});
                     // 判断值的类型后进行强制类型转换
                     String textValue = null;
                     // 其它数据类型都当作字符串简单处理
                     if (value != null && value != "") {
                         textValue = value.toString();
                     }
                     if (textValue != null) {
                         HSSFRichTextString richString = new HSSFRichTextString(textValue);
                         cell.setCellValue(richString);
                     }
                 }
             }
             getExportedFile(workbook, fileName, response);
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
 
     /**
      * 方法说明: 指定路径下生成EXCEL文件
      *
      * @return
      */
     public void getExportedFile(HSSFWorkbook workbook, String name, HttpServletResponse response) throws Exception {
         BufferedOutputStream fos = null;
         try {
             String fileName = name + ".xls";
             response.setContentType("application/x-msdownload");
             response.setHeader("Content-Disposition", "attachment;filename=" + new String(fileName.getBytes("gb2312"), "ISO8859-1"));
             fos = new BufferedOutputStream(response.getOutputStream());
             workbook.write(fos);
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             if (fos != null) {
                 fos.close();
             }
         }
     }
}

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