1. Introduce the org.apache.poi related jar package.
For details, see the previous article: Java implements Excel import data
2. Write Excel export method on the page (I use Layui component here), sample code:
var table = layui.table;
/********** (添加数据)表格头部工具栏监听事件 **********/
table.on('toolbar(insertInfo)', function(obj){
var checkStatus = table.checkStatus(obj.config.id);
var len = checkStatus.data.length;
var count = obj.config.page.count;
switch(obj.event){
case 'export':
var num=table.cache['insertInfo'].length;
if(num==0){
layer.msg('暂无可导出的数据');
}else{
layer.confirm('确定要导出当前的数据？', {
icon: 3,
btn: ['确定', '取消']
}, function (index) {
layer.close(index);
window.open("${ctx}/faultCode/exportToExcel.do?relevanceId=0");
});
}
break;
};
});
3. The controller layer code is as follows:
/**
* 导出Excel
* @param response
* @param session
*/
@SuppressWarnings("unchecked")
@ResponseBody
@RequestMapping("/exportToExcel")
@ApiOperation(value = "导出Excel", notes="导出故障码信息",httpMethod = "POST")
public void exportToExcel(Integer relevanceId, HttpServletResponse response, HttpSession session) {
Map<String, Object> filedNames = new LinkedHashMap<String, Object>();
String titleName = "";
Class<?> objClass = null;
Object obj = null;
try {
List<FaultCodeVo> listFault = null;
//获取需要导出的数据,这里根据需要进行更改
if (relevanceId == 0) {
listFault = (List<FaultCodeVo>) session.getAttribute("listFault");
} else {
listFault = faultCodeService.selectFaultCodeById(relevanceId);
List<FaultCodeVo> listFaultTwo = (List<FaultCodeVo>) session.getAttribute("listFaultTwo");
if(listFaultTwo!=null) {
listFault.addAll(listFaultTwo);
}
}
if (listFault != null) {
// 声明一个list集合接收Dao层查询所返回来的值
obj = listFault;
// excel标题和字段
filedNames.put("dtc", "故障码\r\nDTC");
filedNames.put("hexDtc", "故障码\r\n(hex)");
filedNames.put("englishDescription", "故障码英文描述\r\nEnglish description");
filedNames.put("chineseDescription", "故障码中文描述\r\nChinese description");
filedNames.put("operatingConditions", "故障码运行条件\r\nDTC operating conditions");
filedNames.put("settingConditions", "故障码设置条件\r\nDTC setting conditions");
filedNames.put("settingAfterConditions", "故障码设置时发生的操作\r\nStrategy after DTC appears");
filedNames.put("restoreConditions", "故障恢复条件\r\nDTC resume conditions");
filedNames.put("activateMilRegulations", "激近故障灯原则\r\nActivate MIL regulations");
filedNames.put("milOffRegulations", "熄灭故障灯原则\r\nMil Off regulations");
filedNames.put("clearConditions", "清除故障码条件\r\nClear fault information conditions");
titleName = "故障码信息表";
objClass = FaultCodeVo.class;
// 调用ExcelResponseUtil
ExcelResponseUtil.exportToExcel(response, obj, filedNames, titleName, objClass);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
4. The following is the called tool class (ExcelResponseUtil), sample code:
package com.gx.util;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.text.NumberFormat;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.servlet.http.HttpServletResponse;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
@SuppressWarnings("all")
public class ExcelResponseUtil {
/**
* 导出Excel
*
* @param response
* @param list 导出数据集合
* @param filedNames excel标题&字段 此参数为map，实例为new LinkedHashMap<String, Object>();
* @param titleName 导出文件名
* @param objClass 实体类字节码.class
*/
public static void exportToExcel(HttpServletResponse response, Object list, Map<String, Object> filedNames,
String titleName, Class<?> objClass) {
// 第一步，创建一个webbook，对应一个Excel文件
HSSFWorkbook wb = new HSSFWorkbook();
// 第二步，在webbook中添加一个sheet,对应Excel文件中的sheet
HSSFSheet sheet = wb.createSheet(titleName);
// 设置列宽
sheet.setColumnWidth(0, 15 * 256);
sheet.setColumnWidth(1, 15 * 256);
sheet.setColumnWidth(2, 36 * 256);
sheet.setColumnWidth(3, 36 * 256);
sheet.setColumnWidth(4, 36 * 256);
sheet.setColumnWidth(5, 36 * 256);
sheet.setColumnWidth(6, 36 * 256);
sheet.setColumnWidth(7, 36 * 256);
sheet.setColumnWidth(8, 36 * 256);
sheet.setColumnWidth(9, 36 * 256);
sheet.setColumnWidth(10, 36 * 256);
// 第三步，在sheet中添加表头第0行,注意老版本poi对Excel的行数列数有限制short
HSSFRow row = sheet.createRow(0);
// 第四步，创建单元格，并设置值表头设置表头居中
HSSFCellStyle style = wb.createCellStyle();
style.setWrapText(true);
style.setAlignment(HorizontalAlignment.CENTER);
// 声明列对象
HSSFCell cell = null;
Set<String> fileds = filedNames.keySet();
try {
int i = 0;
// 创建标题
for (String filed : fileds) {
cell = row.createCell(i);
cell.setCellValue(filedNames.get(filed).toString());
cell.setCellStyle(style);
i++;
}
if (list instanceof List) {
List lists = (List) list;
for (int j = 0; j < lists.size(); j++) {
Object obj = objClass.newInstance();// 获取对象实例
row = sheet.createRow(j + 1);
obj = lists.get(j);// 获取一条数据
int k = 0;
for (String filed : fileds) {
int num=0;
String firstBig = filed.substring(0, 1).toUpperCase() + filed.substring(1);
if(firstBig.equals("Name")) {
num=1;
}
// ---获取getter方法，创建内容
Method getMethod = objClass.getMethod("get" + firstBig);
if(getMethod.invoke(obj)==null) {
row.createCell(k).setCellValue("");
}else {
if(num>0) {
String nameInfo=getMethod.invoke(obj).toString();
String[] names=nameInfo.split(",");
String info="";
for (int l = 0; l < names.length; l++) {
if(l==0) {
info=names[l];
}else {
info=info+",\r\n"+names[l];
}
}
row.createCell(k).setCellValue(info);
}else {
row.createCell(k).setCellValue(getMethod.invoke(obj).toString());
}
}
row.getCell(k).setCellStyle(style);
k++;
}
}
}
String fileName = "";// 文件名
// 输出的文件名+以毫秒为单位返回当前时间
// ISO8859-1不能改为UTF-8,否则文件名是乱码
fileName = new String((titleName + System.currentTimeMillis() + ".xls").getBytes(), "ISO8859-1");
// application应用；octet-stream八进制；charset字符集(请求应用)
response.setContentType("application/octet-stream;charset=ISO8859-1");
// Content-Disposition内容配置；attachment附件；(下载完成提示)
response.setHeader("Content-Disposition", "attachment;filename=" + fileName);
OutputStream os = response.getOutputStream();
wb.write(os);
os.flush();
os.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
5. The data to be exported and the exported Excel screenshot are as follows:
