poi的使用
阿帕奇的一个框架,不知道的自行百度一下吧
先说下都有哪些创建方式,以及各个的区别吧
POI的一些使用方法：
创建流程：（上级为下级的载体）
1、创建Workbook（工作薄）；
2、创建Sheet（表单，可以创建多个）；
3、创建Row（行）；
4、创建Cell（单元格）
接下来分别说下工作簿的常用三种形式的区别，他们分别是 1.HSSFWorkbook 2.XSSFWorkbook 3.SXSSFWorkbook
第一种：HSSFWorkbook
针对是 EXCEL2003 版本，扩展名为 .xls;所以此种的局限就是导出的行数至多为 65535 行，
此种因为行数不足七万行所以一般不会发生内存不足的情况（OOM）；
第二种：XSSFWorkbook
这种形式的出现是由于第一种HSSFWorkbook的局限性而产生的，因为其所导出的行数比较少，所以XSSFWookbook应运而生，其对应的是EXCEL2007+(1048576行，16384列)扩展名.xlsx，最多可以导出104万行，不过这样就伴随着一个问题—OOM 内存溢出，原因是你所创建的book、sheet、row、cell等此时是存在内存的并没有持久化，那么随着数据量增大，内存的需求量也就增大，那么很大可能就是要OOM了，那么怎么解决呢？
第三种：SXSSFWorkbook poi.jar 3.8+
第二种遇到的问题该如何解决呢？因为数据量过大导致内存吃不消那么可以让内存到量持久化吗？ 答案是肯定的，此种的情况就是设置最大内存条数，比如，设置最大内存量为5000 rows --new SXSSFWookbook（5000），此时当行数达到5000时，把内存持久化写到文件中，以此逐步写入 避免OOM，那么这样就完美解决了大数据下导出的问题
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XSSFWorkbook workbook = new XSSFWorkbook();
Sheet sheet = workbook.createSheet();
Row rowHeader = sheet.createRow(0);
Cell cell =rowHeader.createCell(0, CellType.STRING);
cell.setCellvalue("报表");
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这些是设置行列的用法,循环组合起来就可以写入报表具体数据,最后面会放一个demo
vue使用axios请求后端去返回下载流这种,必须使用==responseType: ‘blob’==
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| export: params => {
return Axios.post(`${api}report/exportreport`,params,{
responseType: 'blob'})
},
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vue写法
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| buSupportSevConfig.export(params).then(res => {
const url = window.URL.createObjectURL(new Blob([res.data],
{ type: 'application/vnd.ms-excel' }));
const link = document.createElement('a');
link.href = url;
link.setAttribute('download', '综合查询结果导出表.xlsx');
link.style.display = 'none'
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
window.URL.revokeObjectURL(url);
})
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后端写法
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| response.setContentType("application/vnd.ms-excel");
String resultFileName = URLEncoder.encode(fileName, "UTF-8");
response.setHeader("Content-disposition", "attachment;filename=" + resultFileName + ";" + "filename*=utf-8''" + resultFileName);
workbook.write(response.getOutputStream());
workbook.close();
response.flushBuffer();
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设置excel的一些格式
合并单元格
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CellRangeAddress region = new CellRangeAddress(0, 0, 0, headerList.size());
sheet.addMergedRegion(region);
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| XSSFSheet sheet = wb.createSheet("Sheet1");
CreationHelper helper = wb.getCreationHelper();
XSSFDrawing drawing = sheet.createDrawingPatriarch();
Row rowHeadertou = sheet.createRow(1);
ClientAnchor anchor = helper.createClientAnchor();
// 设置斜线的开始位置
anchor.setCol1(0);
anchor.setRow1(1);
// 设置斜线的结束位置
anchor.setCol2(1);
anchor.setRow2(2);
XSSFSimpleShape shape = drawing.createSimpleShape((XSSFClientAnchor) anchor);
// 设置形状类型为线型
shape.setShapeType(ShapeTypes.LINE);
// 设置线宽
shape.setLineWidth(0.5);
// 设置线的风格
shape.setLineStyle(0);
// 设置线的颜色
shape.setLineStyleColor(0, 0, 0);
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效果就是这种
![[danyuange.png]]
需要调整调整宽和高
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sheet.setColumnWidth(i, 50 * 100);
rowHeadertou.setHeight((short)(18*45));
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设置边框以及字体,加粗,居中等问题
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XSSFWorkbook workbook = new XSSFWorkbook();
CellStyle style = workbook.createCellStyle();
style.setAlignment(HorizontalAlignment.CENTER);
style.setVerticalAlignment(VerticalAlignment.CENTER);
Font titleFont = workbook.createFont();
titleFont.setFontName("宋体");
titleFont.setFontHeight((short) 10);
titleFont.setColor((short) 111);
titleFont.setBold(true);
titleFont.setFontHeightInPoints((short) 12);
style.setFont(titleFont);
style.setBorderBottom(BorderStyle.THICK);
style.setBorderRight(BorderStyle.THICK);
style.setBorderTop(BorderStyle.THICK);
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边框这种东西 如果用代码设置 ,会非常麻烦,所以 如果有复杂的单元格设置,或者表头的最好是使用模版,就是先创建一个设置好的模板,然后 用代码去复制一个模板文件,读取模板,往里面写入数据
以下是一个使用模板的工具类:
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| package com.cars.tsbdas.common;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.List;
import javax.servlet.http.HttpServletResponse;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class ExcelUtils {
private static final long serialVersionUID = 1L;
private static final Logger logger = LoggerFactory.getLogger(ExcelUtils.class);
public static final String SUCCESS = "success";
public static final String FAIL = "fail";
private static String templatePath;
private static String exportPath;
public static void exportExcel(List<List<List<String>>> result, HttpServletResponse response, String fileName, int sheetNum, int createRowNum, int createCellNum) {
File newFile = createNewFile(fileName);
InputStream is = null;
XSSFWorkbook workbook = null;
XSSFSheet sheet = null;
try {
is = new FileInputStream(newFile);
workbook = new XSSFWorkbook(is);
if (result.size() > 0) {
for (int i = 0; i < result.size(); i++) {
sheet = workbook.getSheetAt(i);
ExcelUtils.writeIOData(result.get(i), newFile, workbook, sheet, createRowNum, createCellNum);
}
}
InputStream fis = new BufferedInputStream(new FileInputStream(newFile));
byte[] buffer = new byte[fis.available()];
fis.read(buffer);
fis.close();
response.reset();
response.setContentType("text/html;charset=UTF-8");
OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/x-msdownload");
String newName = URLEncoder.encode(fileName + System.currentTimeMillis() + ".xlsx", "UTF-8");
response.addHeader("Content-Disposition", "attachment;filename=\"" + newName + "\"");
response.addHeader("Content-Length", "" + newFile.length());
toClient.write(buffer);
toClient.flush();
toClient.close();
} catch (Exception e1) {
e1.printStackTrace();
logger.error("readExcel" + ExcelUtils.FAIL, e1);
} finally {
try {
if (null != is) {
is.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
private static void writeIOData(List<List<String>> result, File newFile, XSSFWorkbook workbook, XSSFSheet sheet,
int createRowNum, int createCellNum) throws IOException {
FileOutputStream fos = new FileOutputStream(newFile);
XSSFRow row = sheet.getRow(createRowNum);
if (row == null) {
row = sheet.createRow(createRowNum);
}
XSSFCell cell = row.getCell(createCellNum);
if (cell == null) {
cell = row.createCell(createCellNum);
}
int cellNum = result.get(0).size();
for (int m = 1; m < result.size(); m++) {
row = sheet.createRow((int) m + 1);
List<String> tempList = result.get(m);
for (int i = 0; i < cellNum; i++) {
String str = tempList.get(i);
cell = row.createCell(i);
cell.setCellValue(str);
}
}
workbook.write(fos);
fos.flush();
fos.close();
}
public static void fileChannelCopy(File s, File t) {
try {
InputStream in = null;
OutputStream out = null;
try {
in = new BufferedInputStream(new FileInputStream(s), 1024);
out = new BufferedOutputStream(new FileOutputStream(t), 1024);
byte[] buffer = new byte[1024];
int len;
while ((len = in.read(buffer)) != -1) {
out.write(buffer, 0, len);
}
} finally {
if (null != in) {
in.close();
}
if (null != out) {
out.close();
}
}
} catch (Exception e) {
logger.error("templateFile copy exportFile" + ExcelUtils.FAIL, e);
e.printStackTrace();
}
}
private static String getSispPath() {
String classPaths = ExcelUtils.class.getResource("/").getPath();
String[] aa = classPaths.split("/");
String sispPath = "";
for (int i = 1; i < aa.length - 2; i++) {
sispPath += aa[i] + "/";
}
return sispPath;
}
public static File createNewFile(String fileName) {
String path = (getSispPath() + templatePath +"/" + fileName +".xlsx");
File file = new File(path);
String realPath = (getSispPath() + exportPath +"/");
File dir = new File(realPath);
if (!dir.exists()) {
dir.mkdirs();
} else {
ExcelUtils.deleteFile(dir.listFiles());
logger.info("delete exportFile" + ExcelUtils.SUCCESS);
}
File newFile = new File(realPath, fileName);
try {
newFile.createNewFile();
fileChannelCopy(file, newFile);
} catch (Exception e) {
e.printStackTrace();
}
return newFile;
}
private static void deleteFile(File... files) {
for (File file : files) {
if (file.exists()) {
file.delete();
}
}
}
@Value("${template.path}")
public void setTemplatePath(String templatePath) {
ExcelUtils.templatePath = templatePath;
}
@Value("${export.path}")
public void setExportPath(String exportPath) {
ExcelUtils.exportPath = exportPath;
}
}
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这是使用class类反射生成excel文件的工具类
如果数据是动态组合 那就不能用这种class反射方式取生成列
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public static void exportExcel(String fileName, List<?> objects, Class<?> c, HttpServletResponse response) throws Exception {
try {
Workbook workbook = new XSSFWorkbook();
Sheet sheet = workbook.createSheet();
Row rowHeader = sheet.createRow(0);
if (c == null) {
throw new RuntimeException("Class对象不能为空!");
}
Field[] declaredFields = c.getDeclaredFields();
List<String> headerList = new ArrayList<>();
if (declaredFields.length == 0) {
return;
}
for (int i = 0; i < declaredFields.length; i++) {
Cell cell = rowHeader.createCell(i, CellType.STRING);
String headerName = String.valueOf(declaredFields[i].getName());
cell.setCellValue(headerName);
headerList.add(i, headerName);
}
Object obj = c.newInstance();
if (!CollectionUtils.isEmpty(objects)) {
for (int o = 0; o < objects.size(); o++) {
Row rowData = sheet.createRow(o + 1);
for (int i = 0; i < headerList.size(); i++) {
Cell cell = rowData.createCell(i);
Field nameField = c.getDeclaredField(headerList.get(i));
nameField.setAccessible(true);
String value = String.valueOf(nameField.get(objects.get(o)));
cell.setCellValue(value);
}
}
}
response.setContentType("application/vnd.ms-excel");
String resultFileName = URLEncoder.encode(fileName, "UTF-8");
response.setHeader("Content-disposition", "attachment;filename=" + resultFileName + ";" + "filename*=utf-8''" + resultFileName);
workbook.write(response.getOutputStream());
workbook.close();
response.flushBuffer();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
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