POI之匯出Excel
阿新 • • 發佈:2018-12-14
下面簡單給大家介紹poi匯出配置
1.首先匯入依賴
<!--poi-->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.6</version>
</dependency>
2.建立工具類
package javaj.work.util; import org.apache.poi.hssf.usermodel.HSSFWorkbook; import org.apache.poi.ss.usermodel.*; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServletResponse; import java.io.*; import java.lang.reflect.Method; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class ExcelUtil { //引數說明: fileName:檔名 projects:物件集合 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 { //將集合中物件的屬性 對應到 List<Map<String,Object>> List<Map<String,Object>> list=createExcelRecord(projects, keys); ByteArrayOutputStream os = new ByteArrayOutputStream(); try { //將轉換成的Workbook物件通過流形式下載 createWorkBook(list,keys,columnNames).write(os); } catch (IOException e) { e.printStackTrace(); } byte[] content = os.toByteArray(); InputStream is = new ByteArrayInputStream(content); // 設定response引數,可以開啟下載頁面 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 根據屬性名獲取屬性值 * */ 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; } } /** * 建立excel文件物件 * @param keys list中map的key陣列集合 * @param columnNames excel的列名 * */ private static Workbook createWorkBook(List<Map<String, Object>> list, String []keys, String columnNames[]) { // 建立excel工作簿 Workbook wb = new HSSFWorkbook(); // 建立第一個sheet(頁),並命名 Sheet sheet = wb.createSheet(list.get(0).get("sheetName").toString()); // 手動設定列寬。第一個引數表示要為第幾列設;,第二個引數表示列的寬度,n為列高的畫素數。 for(int i=0;i<keys.length;i++){ sheet.setColumnWidth((short) i, (short) (35.7 * 150)); } // 建立第一行 Row row = sheet.createRow((short) 0); // 建立兩種單元格格式 CellStyle cs = wb.createCellStyle(); CellStyle cs2 = wb.createCellStyle(); // 建立兩種字型 Font f = wb.createFont(); Font f2 = wb.createFont(); // 建立第一種字型樣式(用於列名) f.setFontHeightInPoints((short) 10); f.setColor(IndexedColors.BLACK.getIndex()); f.setBoldweight(Font.BOLDWEIGHT_BOLD); // 建立第二種字型樣式(用於值) f2.setFontHeightInPoints((short) 10); f2.setColor(IndexedColors.BLACK.getIndex()); // 設定第一種單元格的樣式(用於列名) 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); // 設定第二種單元格的樣式(用於值) 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); //設定列名 for(int i=0;i<columnNames.length;i++){ Cell cell = row.createCell(i); cell.setCellValue(columnNames[i]); cell.setCellStyle(cs); } //設定每行每列的值 for (short i = 1; i < list.size(); i++) { // Row 行,Cell 方格 , Row 和 Cell 都是從0開始計數的 // 建立一行,在頁sheet上 Row row1 = sheet.createRow((short) i); // 在row行上建立一個方格 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; } }
3.pojo
public class Student {
private int no;
private String name;
private int age;
//此處省略getter和setter
}
4.配置controller
@RequestMapping(value = "download") public void index(HttpServletResponse response){ String fileName = "人員檔案列表"; List<Student> students = new ArrayList<Student>(); for (int i = 0;i<20 ;i++){ Student student = new Student(); student.setAge(i+10); student.setName("張三"+i); student.setNo(i); students.add(student); } // 列名 String columnNames[] = { "ID", "姓名", "年齡" }; // map中的key String keys[] = { "no", "name", "age" }; try { ExcelUtil.start_download(response, fileName, students,columnNames, keys); } catch (IOException e) { e.printStackTrace(); } }
5.頁面
<a href="download.do">匯出Excel</a>