POI导入和导出到excel
使用到的依赖:
org.apache.poi
poi
3.8
org.apache.poi
poi-ooxml
3.8
版本自己控制。
两种导出方式,HSSF和XSSF，其中HSSF是将数据一次性写入到内存里，再一次性写出到excel，对于内存消耗比较大，数据量太大的话会导致内存溢出，但是效率比较快，最大值63556。
XSSF是读一部分再写一部分，再读再写，内存消耗会小一些，但是效率比HSSF慢。
使用的时候，HSSF加入poi的依赖就可以使用，而XSSF需要加上面两个依赖。
HSSF只操作.xls文件(97–03版excel)一个sheet中行有限制,最大是65536（将数据一次性写入内容，再写出）
1、使用HSSF导出到excel
public class WirteExcelHSSFTest {
public static void main(String[] args) throws Exception{
//创建文件输出流
FileOutputStream out = new FileOutputStream("E:\\upload\\test.xls");
//创建一个工作簿
Workbook wb = new HSSFWorkbook();
for(int j = 0; j< 10; j++){
//创建sheet--工作表
Sheet sheet = wb.createSheet();
wb.setSheetName(j,"sheet"+ j);//指定sheet得名称
for(int rowNum = 0; rowNum < 65536; rowNum++){
//创建一行
Row row = sheet.createRow(rowNum);//创建第一行
//一行创建10个单元格
for(int cellNum = 0; cellNum < 10; cellNum++){
//在行里创建单元格
Cell cell = row.createCell(cellNum);
//向单元格中写入数据
cell.setCellValue(cellNum);
}
}
}
wb.write(out);//输出文件内容
}
}
2、使用XSSF导出数据到excel
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.util.CellReference;
import org.apache.poi.xssf.streaming.SXSSFSheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import java.io.FileOutputStream;
import java.io.IOException;
public class WriteEexceXSSFTest {
public static void main(String[] args) throws Exception {
//创建SXSSFworkBook（关闭自动刷新并在内存中积累所有的行）
SXSSFWorkbook wb = new SXSSFWorkbook(-1);
//创建一个sheet
Sheet sheet = wb.createSheet();
for(int rownum = 0; rownum < 100000;rownum++){
//创建一行
Row row = sheet.createRow(rownum);
//创建单元格
for(int cellNum = 0; cellNum < 10; cellNum++){
Cell cell = row.createCell(cellNum);
//单元格地址
String address = new CellReference(cell).formatAsString();
cell.setCellValue(address);
}
//达到一万行后就向磁盘写入一次
if(rownum % 10000 == 0){
//保留最后100行并冲洗所有的其他行
((SXSSFSheet)sheet).flushRows(100);
}
}
FileOutputStream out = new FileOutputStream("E:\\upload\\test.xls");
wb.write(out);//将临时文件合并，写入最终文件
out.close();
}
}
3、使用HSSF将excel数据插入到数据库
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import java.io.FileInputStream;
import java.io.InputStream;
public class ReadExcelHSSF {
public static void main(String[] args) throws Exception{
ReadExcelHSSF readExcelHSSF = new ReadExcelHSSF();
readExcelHSSF.readXls();
}
public void readXls() throws Exception{
//文件输入流
InputStream is = new FileInputStream("E:/upload/test.xls");
//创建workBook--工作簿
HSSFWorkbook hssfWorkbook = new HSSFWorkbook(is);
//解析workbook的内容
for(int numSheet = 0; numSheet < hssfWorkbook.getNumberOfSheets(); numSheet++){
//得到workBook中某个sheet(序号是从0开始)
HSSFSheet hssfSheet = hssfWorkbook.getSheetAt(numSheet);
if(hssfSheet == null){
continue;
}
//遍历循环row
for(int rowNum = 1; rowNum <= hssfSheet.getLastRowNum();rowNum++){
//读取每一行数据，rowNum指定行下标从0开始
HSSFRow hssfRow = hssfSheet.getRow(rowNum);
//读取单元格内容
for(int cellNum= 0; cellNum <= hssfRow.getLastCellNum(); cellNum ++){
//读取一行中的某个单元格的内容（cellNum指定单元格的下标，从0开始）
HSSFCell cell = hssfRow.getCell(cellNum);
if(cell == null){
continue;
}
//插入到数据库，我这里就不演示了，直接打印
System.out.println(cell.getStringCellValue());
}
}
}
}
}
4、使用XSSF将excel数据读取到数据库
import org.apache.poi.hssf.eventusermodel.HSSFEventFactory;
import org.apache.poi.hssf.eventusermodel.HSSFListener;
import org.apache.poi.hssf.eventusermodel.HSSFRequest;
import org.apache.poi.hssf.record.*;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
public class ReadExcelXSSFTest implements HSSFListener {
private SSTRecord sstrec;
/**
* This method listens for incoming records and handles them as required.
*
* @param record
* The record that was found while reading.
*/
public void processRecord(Record record) {
switch (record.getSid()) {
// the BOFRecord can represent either the beginning of a sheet or the
// workbook
case BOFRecord.sid:
BOFRecord bof = (BOFRecord) record;
if (bof.getType() == bof.TYPE_WORKBOOK) {
System.out.println("Encountered workbook");
// assigned to the class level member
} else if (bof.getType() == bof.TYPE_WORKSHEET) {
System.out.println("Encountered sheet reference");
}
break;
case BoundSheetRecord.sid:
BoundSheetRecord bsr = (BoundSheetRecord) record;
System.out.println("New sheet named: " + bsr.getSheetname());
break;
case RowRecord.sid:
RowRecord rowrec = (RowRecord) record;
System.out.println("Row found, first column at "
+ rowrec.getFirstCol() + " last column at "
+ rowrec.getLastCol());
break;
case NumberRecord.sid:
NumberRecord numrec = (NumberRecord) record;
System.out.println("Cell found with value " + numrec.getValue()
+ " at row " + numrec.getRow() + " and column "
+ numrec.getColumn());
break;
// SSTRecords store a array of unique strings used in Excel.
case SSTRecord.sid:
sstrec = (SSTRecord) record;
for (int k = 0; k < sstrec.getNumUniqueStrings(); k++) {
System.out.println("String table value " + k + " = "
+ sstrec.getString(k));
}
break;
case LabelSSTRecord.sid:
LabelSSTRecord lrec = (LabelSSTRecord) record;
System.out.println(lrec.getRow()+"String cell found with value "
+ sstrec.getString(lrec.getSSTIndex()));
break;
}
}
/**
* Read an excel file and spit out what we find.
*
* @param args
* Expect one argument that is the file to read.
* @throws IOException
* When there is an error processing the file.
官方例子读取大数据量xls文件没有内存溢出问题
*/
public static void main(String[] args) throws IOException {
// create a new file input stream with the input file specified
// at the command line
FileInputStream fin = new FileInputStream("E:\\upload\\test.xls");
// create a new org.apache.poi.poifs.filesystem.Filesystem
POIFSFileSystem poifs = new POIFSFileSystem(fin);
// get the Workbook (excel part) stream in a InputStream
InputStream din = poifs.createDocumentInputStream("Workbook");
// construct out HSSFRequest object
HSSFRequest req = new HSSFRequest();
// lazy listen for ALL records with the listener shown above
//添加一个事件驱动
req.addListenerForAllRecords(new ReadExcelXSSFTest());
// create our event factory
HSSFEventFactory factory = new HSSFEventFactory();
// process our events based on the document input stream
factory.processEvents(req, din);
// once all the events are processed close our file input stream
fin.close();
// and our document input stream (don't want to leak these!)
din.close();
System.out.println("done.");
}
}
5、实战中将poi封装成一个工具类，项目中直接调用类中的方法，返回下载的链接地址：
import java.io.FileOutputStream;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.xssf.streaming.SXSSFSheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.java.pojo.Ypxx;
/**
* excel导出的封装类
*/
public class ExcelExportSXXSSF {
// 定义工作表
private SXSSFWorkbook wb;
/**
* 定义工作表中的sheet
*/
private Sheet sh;
/**
* 定义保存在内存中的数量,-1表示手动控制
*/
private int flushRows;
/** 导出文件行数 */
private int rownum;
/** 导出文件列数 */
private int colnum;
/** 导出文件的存放路径 */
private String filePath;
/** 下载导出文件的路径 */
private String fileWebPath;
/**文件名称前缀*/
private String filePrefix;
/**导出文件全路径*/
private String fileAllPath;
/** 导出文件列标题 */
private List fieldNames;
/**导出文件每列代码，用于反射获取对象属性值*/
private List fieldCodes;
private ExcelExportSXXSSF() {
}
/**
* 开始导出方法
*
* @param filePath
* 导出文件存放物理路径
* @param fileWebPath
* 导出文件web下载路径
* @param filePrefix
* 导出文件名的前缀
* @param flushRows
* 存放在内存的数据量
* @param fieldNames
* 导出文件列标题
* @param fieldCodes
* 导出数据对象的字段名称
* @param flushRows
* 写磁盘控制参数
* @return
*/
public static ExcelExportSXXSSF start(String filePath, String fileWebPath,String filePrefix,
List fieldNames,List fieldCodes, int flushRows) throws Exception {
ExcelExportSXXSSF excelExportSXXSSF = new ExcelExportSXXSSF();
excelExportSXXSSF.setFilePath(filePath);
excelExportSXXSSF.setFileWebPath(fileWebPath);
excelExportSXXSSF.setFilePrefix(filePrefix);
excelExportSXXSSF.setFieldNames(fieldNames);
excelExportSXXSSF.setFieldCodes(fieldCodes);
excelExportSXXSSF.setWb(new SXSSFWorkbook(flushRows));//创建workbook
excelExportSXXSSF.setSh(excelExportSXXSSF.getWb().createSheet());//创建sheet
excelExportSXXSSF.writeTitles();
return excelExportSXXSSF;
}
/**
* 设置导入文件的标题
* 开始生成导出excel的标题
* @throws Exception
*/
private void writeTitles() throws Exception {
rownum = 0;//第0行
colnum = fieldNames.size();//根据列标题得出列数
Row row = sh.createRow(rownum);
for (int cellnum = 0; cellnum < colnum; cellnum++) {
Cell cell = row.createCell(cellnum);
cell.setCellValue(fieldNames.get(cellnum));
}
}
/**
* 向导出文件写数据
*
* @param datalist
* 存放Object对象，仅支持单个自定义对象，不支持对象中嵌套自定义对象
* @return
*/
public void writeDatasByObject(List datalist) throws Exception {
for (int j = 0; j < datalist.size(); j++) {
rownum = rownum + 1;
Row row = sh.createRow(rownum);
for (int cellnum = 0; cellnum < fieldCodes.size(); cellnum++) {
Object owner = datalist.get(j);
Object value = invokeMethod(owner, fieldCodes.get(cellnum),
new Object[] {});
Cell cell = row.createCell(cellnum);
cell.setCellValue(value!=null?value.toString():"");
}
}
}
/**
* 向导出文件写数据
*
* @param datalist
* 存放字符串数组
* @return
*/
public void writeDatasByString(List datalist) throws Exception {
rownum = rownum + 1;
Row row = sh.createRow(rownum);
int datalist_size = datalist.size();
for (int cellnum = 0; cellnum < colnum; cellnum++) {
Cell cell = row.createCell(cellnum);
if(datalist_size>cellnum){
cell.setCellValue(datalist.get(cellnum));
}else{
cell.setCellValue("");
}
}
}
/**
* 手动刷新方法,如果flushRows为-1则需要使用此方法手动刷新内存
*
* @throws Exception
*/
public void flush(int flushNum) throws Exception {
((SXSSFSheet) sh).flushRows(flushNum);
}
/**
* 导出文件
*
* @throws Exception
*/
public String exportFile() throws Exception {
String filename = filePrefix+"_"+System.currentTimeMillis() + ".xlsx";
FileOutputStream out = new FileOutputStream(filePath + filename);
wb.write(out);
out.flush();
out.close();
setFileAllPath(fileWebPath + filename);
return fileWebPath + filename;
}
/**
* 反射方法，通过get方法获取对象属性
*
* @param owner
* @param fieldname
* @param args
* @return
* @throws Exception
*/
private Object invokeMethod(Object owner, String fieldname, Object[] args)
throws Exception {
String methodName = "get" + fieldname.substring(0, 1).toUpperCase()
+ fieldname.substring(1);
Class ownerClass = owner.getClass();
Class[] argsClass = new Class[args.length];
for (int i = 0, j = args.length; i < j; i++) {
argsClass[i] = args[i].getClass();
}
Method method = ownerClass.getMethod(methodName, argsClass);
return method.invoke(owner, args);
}
public SXSSFWorkbook getWb() {
return wb;
}
public void setWb(SXSSFWorkbook wb) {
this.wb = wb;
}
public Sheet getSh() {
return sh;
}
public void setSh(Sheet sh) {
this.sh = sh;
}
public int getFlushRows() {
return flushRows;
}
public void setFlushRows(int flushRows) {
this.flushRows = flushRows;
}
public String getFilePath() {
return filePath;
}
public void setFilePath(String filePath) {
this.filePath = filePath;
}
public String getFileWebPath() {
return fileWebPath;
}
public void setFileWebPath(String fileWebPath) {
this.fileWebPath = fileWebPath;
}
public List getFieldNames() {
return fieldNames;
}
public void setFieldNames(List fieldNames) {
this.fieldNames = fieldNames;
}
public List getFieldCodes() {
return fieldCodes;
}
public void setFieldCodes(List fieldCodes) {
this.fieldCodes = fieldCodes;
}
public int getRownum() {
return rownum;
}
public String getFilePrefix() {
return filePrefix;
}
public void setFilePrefix(String filePrefix) {
this.filePrefix = filePrefix;
}
public int getColnum() {
return colnum;
}
public String getFileAllPath() {
return fileAllPath;
}
public void setFileAllPath(String fileAllPath) {
this.fileAllPath = fileAllPath;
}
}
6、将数据库查询出的列表数据导出到excel
//实现excel的导出功能
@RequestMapping("/exportYpxxSubmit")
@ResponseBody
public SubmitResultInfo exportYpxxSubmit(YpxxQueryVo ypxxQueryVo) throws Exception{
//调用封装类执行导出
//1.定义导出数据的title
List filedNames = new ArrayList<>();
filedNames.add("流水号");
filedNames.add("通用名");
filedNames.add("剂型");
filedNames.add("规格");
filedNames.add("转换系数");
filedNames.add("生产企业");
filedNames.add("商品名称");
filedNames.add("中标价格");
filedNames.add("交易状态");
//2.告诉导出数据list中的对象的属性，让excelExportSXXSSF通过反射货到对象的值
List fildCodes = new ArrayList<>();
fildCodes.add("bm"); //药品流水号
fildCodes.add("mc");
fildCodes.add("jx");
fildCodes.add("gg");
fildCodes.add("zhxs");
fildCodes.add("scqymc");
fildCodes.add("spmc");
fildCodes.add("zbjg");
fildCodes.add("jyzt");
//3.开始到处
String filePath = "E:\\upload";
String filePrefix = "uploadypxx";
int flushRows = 100; //-1表示关闭自动刷新，手动控制写入磁盘时机，其他数据表示 多少数据在内存中保存超过的就写入到磁盘
ExcelExportSXXSSF excelExportSXXSSF = ExcelExportSXXSSF.start(filePath,"http://localhost:80/",filePrefix, filedNames, fildCodes, flushRows);
//导出得数据通过service取得
List list = ypxxService.findYpxxList(ypxxQueryVo);
//执行导出
excelExportSXXSSF.writeDatasByObject(list);
//输出文件,返回下载文件的http地址，已经包括目录
String webpath = excelExportSXXSSF.exportFile();
System.out.println("下载路径：" + webpath);
//list就是查询到的目录列表 webpath就是下载地址
return ResultUtil.createSubmitResult(ResultUtil.createSuccess(Config.MESSAGE,313,new Object[]{list.size(),webpath}));
}