Java学习大纲(持续更新):https://blog.csdn.net/weixin_39778570/article/details/94667501
更多IT学习资源:https://blog.csdn.net/weixin_39778570/article/details/100052454
Excel文件导入
从前端传递excel文件到后端,通过ajax
这里使用的是lay-ui的控件
upload.render({
elem: '#test' //绑定元素
,accept: 'file'
,url: '/xxx/xxx/upload' //上传接口
,before: function(obj) {
layer.msg('文件上传中...', {
icon: 16,
shade: 0.01,
time: 0
})
},
done: function(res) {
layer.close(layer.msg(res.msg));//关闭上传提示窗口
}
});
后端Controller获取数据并处理
@RequestMapping("upload")
@ResponseBody
public BaseResponse doUpload(HttpServletRequest request) throws IOException {
MultipartHttpServletRequest mreq = null;
if(request instanceof MultipartHttpServletRequest){
mreq = (MultipartHttpServletRequest) request;
}else {
return BaseResponse.fail ();
}
try{
boolean flag = xxx.analysisFile(mreq);
if(!flag){
return BaseResponse.fail ();
}
return BaseResponse.success();
}catch (Exception e){
return BaseResponse.fail ();
}
}
Server层xxx.analysisFile(mreq)
public boolean analysisFile(MultipartHttpServletRequest mreq){
List<Map> maps = null;
try {
maps = ExcelUtils.analysisFile (mreq);
} catch (Exception e) {
return false;
}
if(maps==null){
return false;
}else{
// 处理信息
return true;
}
}
解析Excel文件请求的工具类(可以直接复用)
import org.apache.poi.ss.usermodel.*;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import java.io.IOException;
import java.io.InputStream;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.List;
/** * Excel处理工具 */
public class ExcelUtils {
/** * 处理HTTP请求里是file文件 * @param mreq * @return 返回List<Map>每个Map存放一行 */
public static List<Map> analysisFile(MultipartHttpServletRequest mreq)throws Exception{
InputStream inputStream= null;
try {
inputStream = mreq.getFile ("file").getInputStream ();
} catch (IOException e) {
throw e;
}
String fileName = mreq.getFile ("file").getOriginalFilename ();
Workbook workbook = null;
try {
//判断什么类型文件
if (fileName.endsWith(".xls") || fileName.endsWith(".xlsx")) {
workbook = WorkbookFactory.create(inputStream);
}
} catch (Exception e) {
throw e;
}
if (workbook == null) {
return null;
} else {
//获取所有的工作表的的数量
int numOfSheet = workbook.getNumberOfSheets ();
System.out.println (numOfSheet + "--->numOfSheet");
List<Map> mapList = new ArrayList<> ();
//遍历表
for (int i = 0; i < numOfSheet; i++) {
//获取一个sheet也就是一个工作本。
Sheet sheet = workbook.getSheetAt (i);
if (sheet == null) {
continue;
}
//获取一个sheet有多少Row
int lastRowNum = sheet.getLastRowNum ();
if (lastRowNum == 0) {
continue;
}
Row row;
// 行头
List<String> headName = new ArrayList<>();
if(lastRowNum>0){
row = sheet.getRow (0);
// 获取一个Row有多少Cell
short lastCellNum = row.getLastCellNum ();
for (int k = 0; k <= lastCellNum; k++) {
if (row.getCell (k) == null) {
continue;
}
String res = getCellVal(row.getCell (k));
headName.add (res);
}
}
// 每一行的内容
for (int j = 1; j <= lastRowNum; j++) {
row = sheet.getRow (j);
if (row == null) {
continue;
}
//获取一个Row有多少Cell
short lastCellNum = row.getLastCellNum ();
Map<String,String> rowMap = new HashMap ();
for (int k = 0; k <= lastCellNum; k++) {
if (row.getCell (k) == null) {
continue;
}
String res = getCellVal(row.getCell (k));
rowMap.put (headName.get (k), res);
}
mapList.add (rowMap);
}
}
return mapList;
}
}
private static String getCellVal(Cell cell) {
SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd"); //日期格式yyyy-mm-dd
DecimalFormat df = new DecimalFormat("0");
String val;
switch (cell.getCellType()) {
case Cell.CELL_TYPE_NUMERIC:
if (DateUtil.isCellDateFormatted(cell)) {
val = fmt.format(cell.getDateCellValue()); //日期型
} else {
val = df.format(cell.getNumericCellValue()); //数字型
}
break;
case Cell.CELL_TYPE_STRING: //文本类型
val = cell.getStringCellValue();
break;
case Cell.CELL_TYPE_BOOLEAN: //布尔型
val = String.valueOf(cell.getBooleanCellValue());
break;
case Cell.CELL_TYPE_BLANK: //空白
val = cell.getStringCellValue();
break;
case Cell.CELL_TYPE_ERROR: //错误
val = "错误";
break;
case Cell.CELL_TYPE_FORMULA: //公式
try {
val = String.valueOf(cell.getStringCellValue());
} catch (IllegalStateException e) {
val = String.valueOf(cell.getNumericCellValue());
}
break;
default:
val = cell.getRichStringCellValue() == null ? null : cell.getRichStringCellValue().toString();
}
return val;
}
}
Excel 文件导出
由于ajax 是无法直接导出excel的,因为ajax返回值只能是字符流,而导出excel是后台往浏览器中写入二进制的字节流
流程是这样的,前端发送一个ajax请求到后端,后端缓存请求数据,并保存请求，返回给浏览器一个UUID,浏览器通过UUID再发起请求(可以通过window.location.href的方式),服务器把excel文件写入response中显示到浏览器
前端请求
form.on('submit(export)', function(data){
var field = data.field;
$.ajax({
url:'<@spring.url "/xxx/ttt/export"/>',
dataType : "json",
data : JSON.stringify(field),
contentType : "application/json; charset=utf-8",
type : "POST",
async: true,
success : function(data){
var key =data.msg
window.location.href = "/xxx/ttt/doExport?key="+key
}
})
});
后端处理请求,先缓存,再查询(为了简单起见这里就不查询了),再清楚缓存
/** * 由于ajax无法直接导出excel,所以第一次把请求生成的ExcelParam缓存起来,然后前端再次window.open(url); */
public static Map<String, Xxx> excelParamCache = new ConcurrentHashMap<> ();
//第一步缓存参数
@SuppressWarnings("unchecked")
@RequestMapping(value = "/export")
@ResponseBody
public BaseResponse export(@RequestBody Xxx requestVo) {
String key = UUID.randomUUID().toString();
excelParamCache.put(key,requestVo);
return new BaseResponse(0,key);
}
@RequestMapping(value = "doExport")
public BaseResponse doExport(String key, HttpServletRequest request, HttpServletResponse response) throws IOException {
if(key==null){
return BaseResponse.fail ();
}
try {
if(!excelParamCache.containsKey (key)){
return BaseResponse.fail ();
}
HSSFWorkbook workbook = new HSSFWorkbook ();
HSSFSheet sheet = workbook.createSheet ("信息表");
// 设置要导出的文件的名字
String fileName = "报表-" + new Date () + ".xls";
// 新增数据行，并且设置单元格数据
int rowNum = 1;
// headers表示excel表中第一行的表头 在excel表中添加表头
String[] headers = { "id", "uid", "地址", "城市"};
HSSFRow row = sheet.createRow (0);
for (int i = 0; i < headers.length; i++) {
HSSFCell cell = row.createCell (i);
HSSFRichTextString text = new HSSFRichTextString (headers[i]);
cell.setCellValue (text);
}
//在表中存放查询到的数据放入对应的列
for (int i = 0; i < 4; i++) {
HSSFRow row1 = sheet.createRow (rowNum);
row1.createCell (0).setCellValue (1);
row1.createCell (1).setCellValue (2);
row1.createCell (2).setCellValue (3);
row1.createCell (3).setCellValue ("hhh");
rowNum++;
}
response.setContentType ("application/octet-stream");
response.setHeader ("Content-disposition", "attachment;filename=" + fileName);
response.flushBuffer ();
workbook.write (response.getOutputStream ());
}catch (Exception e){
excelParamCache.remove(key);
}finally {
excelParamCache.remove(key);
}
return BaseResponse.success ();
}
依赖
<!-- 文件上传 -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.14</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>3.14</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml-schemas</artifactId>
<version>3.14</version>
</dependency>
执行结果
