java8 POI 读取写入EXCEL

实例所需bean

ExcelColumn

import java.lang.annotation.*;

/**
* Created by admin on 2017/1/9.
*/
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ExcelColumn {
String value() default "";

/**
*从1开始
* @return
*/
int col() default 0;
}

ExcelUtils

import com.cs.test.utils.DateFormatter;
import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.lang3.BooleanUtils;
import org.apache.commons.lang3.CharUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.math.NumberUtils;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.math.BigDecimal;
import java.util.*;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;

/**
* Created by admin on 2017/1/17.
*/
public class ExcelUtils {

private final static Logger log = LoggerFactory.getLogger(ExcelUtils.class);

private final static String EXCEL2003 = "xls";
private final static String EXCEL2007 = "xlsx";

public static <T> List<T> readExcel(String path, Class<T> cls){
List<T> dataList = new ArrayList<>();

Workbook workbook = null;
try {
if(path.endsWith(EXCEL2007)){
FileInputStream is = new FileInputStream(new File(path));
workbook = new XSSFWorkbook(is);
}
if(path.endsWith(EXCEL2003)){
FileInputStream is = new FileInputStream(new File(path));
workbook = new HSSFWorkbook(is);
}
if(workbook != null){
//类映射  注解 value-->bean columns
Map<String, List<Field>> classMap = new HashMap<>();
Field[] fields = cls.getDeclaredFields();
for (Field field : fields) {
ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
if(annotation != null){
String value = annotation.value();
if(StringUtils.isBlank(value)){
continue;
}
if(!classMap.containsKey(value)){
classMap.put(value, new ArrayList<>());
}
field.setAccessible(true);
classMap.get(value).add(field);
}
}
//索引-->columns
Map<Integer, List<Field>> reflectionMap = new HashMap<>();
Sheet sheet = workbook.getSheetAt(0);//默认读取第一个sheet

boolean firstRow = true;
for (int i = sheet.getFirstRowNum(); i <= sheet.getLastRowNum(); i++) {
Row row = sheet.getRow(i);

if(firstRow){//首行  提取注解
for (int j = row.getFirstCellNum(); j <= row.getLastCellNum(); j++) {
Cell cell = row.getCell(j);
String cellValue = getCellValue(cell);
if(classMap.containsKey(cellValue)){
reflectionMap.put(j, classMap.get(cellValue));
}
}
firstRow = false;
}else{
if(row == null){//忽略空白行
continue;
}

try {
T t = cls.newInstance();
boolean allBlank = true;//判断是否为空白行
for (int j = row.getFirstCellNum(); j <= row.getLastCellNum(); j++) {
if(reflectionMap.containsKey(j)){
Cell cell = row.getCell(j);
String cellValue = getCellValue(cell);
if(StringUtils.isNotBlank(cellValue)){
allBlank = false;
}
List<Field> fieldList = reflectionMap.get(j);
for (Field field : fieldList) {
try {
handleField(t, cellValue, field);
}catch (Exception e){
log.error(String.format("reflect field:%s value:%s exception!", field.getName(), cellValue), e);
}
}
}
}
if(!allBlank){
dataList.add(t);
}else{
log.warn(String.format("row:%s is blank ignore!", i));
}
}catch (Exception e){
log.error(String.format("parse row:%s exception!", i), e);
}
}
}
}
}catch (Exception e){
log.error(String.format("parse excel exception!"), e);
}finally {
if(workbook != null){
try {
workbook.close();
}catch (Exception e){
}
}
}
return dataList;
}

private static <T> void handleField(T t, String value, Field field) throws Exception {
Class<?> type = field.getType();
if(type == null || type == void.class || StringUtils.isBlank(value)){
return;
}
if(type == Object.class){
field.set(t, value);
}else if(type.getSuperclass() == null || type.getSuperclass() == Number.class){//数字类型
if(type == int.class || type == Integer.class){
field.set(t, NumberUtils.toInt(value));
}else if(type == long.class || type == Long.class){
field.set(t, NumberUtils.toLong(value));
}else if(type == byte.class || type == Byte.class){
field.set(t, NumberUtils.toByte(value));
}else if(type == short.class || type == Short.class){
field.set(t, NumberUtils.toShort(value));
}else if(type == double.class || type == Double.class){
field.set(t, NumberUtils.toDouble(value));
}else if(type == float.class || type == Float.class){
field.set(t, NumberUtils.toFloat(value));
}else if(type == char.class || type == Character.class){
field.set(t, CharUtils.toChar(value));
}else if(type == boolean.class){
field.set(t, BooleanUtils.toBoolean(value));
}else if(type == BigDecimal.class){
field.set(t, new BigDecimal(value));
}
} else if(type == Boolean.class){
field.set(t, BooleanUtils.toBoolean(value));
} else if(type == Date.class){
field.set(t, DateFormatter.parser(value));
} else if(type == String.class){
field.set(t, value);
}else{
Constructor<?> constructor = type.getConstructor(String.class);
field.set(t, constructor.newInstance(value));
}
}

private static String getCellValue(Cell cell){
if(cell == null){
return "";
}
if(cell.getCellType() == cell.CELL_TYPE_NUMERIC){
if(DateUtil.isCellDateFormatted(cell)){
return DateFormatter.longDate(DateUtil.getJavaDate(cell.getNumericCellValue()));
}else{
return new BigDecimal(cell.getNumericCellValue()).toString();
}
}else if(cell.getCellType() == cell.CELL_TYPE_STRING){
return StringUtils.trimToEmpty(cell.getStringCellValue());
}else if(cell.getCellType() == cell.CELL_TYPE_FORMULA){
return  StringUtils.trimToEmpty(cell.getCellFormula());
}else if(cell.getCellType() == cell.CELL_TYPE_BLANK){
return "";
}else if(cell.getCellType() == cell.CELL_TYPE_BOOLEAN){
return String.valueOf(cell.getBooleanCellValue());
}else if(cell.getCellType() == cell.CELL_TYPE_ERROR){
return "ERROR";
}else{
return cell.toString().trim();
}

}

public static <T> void writeExcel(String path, List<T> dataList, Class<T> cls) {
Field[] fields = cls.getDeclaredFields();
List<Field> fieldList = Arrays.stream(fields).filter(field->{
ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
if(annotation != null && annotation.col() > 0) {
field.setAccessible(true);
return true;
}
return false;
}).sorted(Comparator.comparing(field->{
int col = 0;
ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
if(annotation != null){
col = annotation.col();
}
return col;
})).collect(Collectors.toList());

Workbook wb = new XSSFWorkbook();
Sheet sheet = wb.createSheet("demo sheet");

AtomicInteger ai = new AtomicInteger();

{
Row row = sheet.createRow(ai.getAndIncrement());
AtomicInteger aj = new AtomicInteger();

//写入头部
fieldList.forEach(field->{
ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
String columnName = "";
if(annotation != null){
columnName = annotation.value();
}
Cell cell = row.createCell(aj.getAndIncrement());

CellStyle cellStyle = wb.createCellStyle();
cellStyle.setFillForegroundColor(IndexedColors.GREEN.getIndex());
cellStyle.setFillPattern(CellStyle.SOLID_FOREGROUND);
cellStyle.setAlignment(CellStyle.ALIGN_CENTER);

Font font = wb.createFont();
font.setBoldweight(Font.BOLDWEIGHT_BOLD);
cellStyle.setFont(font);
cell.setCellStyle(cellStyle);
cell.setCellValue(columnName);
});
}

if(CollectionUtils.isNotEmpty(dataList)){
dataList.forEach(t->{
Row row = sheet.createRow(ai.getAndIncrement());
AtomicInteger aj = new AtomicInteger();

fieldList.forEach(field->{
Class<?> type = field.getType();

Object value = "";
try {
value = field.get(t);
}catch (Exception e){
e.printStackTrace();
}
Cell cell = row.createCell(aj.getAndIncrement());

if(value != null){
if(type == Date.class){
cell.setCellValue(DateFormatter.longDate((Date) value));
}else{
cell.setCellValue(value.toString());
}
}
});
});

}

//冻结窗格
wb.getSheet("demo sheet").createFreezePane(0,1,0,1);

File file = new File(path);
if(file.exists()){
file.delete();
}
try {
wb.write(new FileOutputStream(file));
}catch (Exception e){
e.printStackTrace();
}
}

}

ExcelDemo

import com.alibaba.fastjson.JSON;
import lombok.Data;

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

/**
* Created by admin on 2017/1/17.
*/
@Data
public class ExcelDemo {
@ExcelColumn(value="ID", col=1)
private int id;
@ExcelColumn(value="名称", col=2)
private String name;

public static void main(String[] args){
long t1 = System.currentTimeMillis();
ExcelUtils.writeExcel(".\\test.xlsx", IntStream.rangeClosed(1,10).mapToObj(i->{
ExcelDemo excelDemo = new ExcelDemo();
excelDemo.setId(i);
excelDemo.setName(String.format("name-%s", i));
return excelDemo;
}).collect(Collectors.toList()), ExcelDemo.class);

long t2 = System.currentTimeMillis();
System.out.println(String.format("write over! cost:%sms", (t2-t1)));

long t3 = System.currentTimeMillis();
System.out.println(String.format("read over! cost:%sms", (t3-t2)));

List<ExcelDemo> excelDemos = ExcelUtils.readExcel(".\\test.xlsx", ExcelDemo.class);
excelDemos.stream().forEach(b->System.out.println(JSON.toJSONString(b, true)));
}
}

输出结果

write over! cost:907ms
{
"id":1,
"name":"name-1"
}
{
"id":2,
"name":"name-2"
}
{
"id":3,
"name":"name-3"
}
{
"id":4,
"name":"name-4"
}
{
"id":5,
"name":"name-5"
}
{
"id":6,
"name":"name-6"
}
{
"id":7,
"name":"name-7"
}
{
"id":8,
"name":"name-8"
}
{
"id":9,
"name":"name-9"
}
{
"id":10,
"name":"name-10"
}
read over! cost:136ms