java poi 生成excel单个或多个表头

使用poi生成双表头，写的不是很好，还有很多可以改进的地方，希望大家谅解，此方法采用了java的反射机制来排除一些不需要导出的字段，如果一张表有一百多个字段的话写的有点累人，也容易出现问题，但是用用还是可以的，导出的效率也还有可以改进的地方。使用poi-3.8版本的Jar包

1,：TableExcel类

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Field;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.usermodel.HSSFRichTextString;
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.hssf.util.HSSFColor;
import org.apache.poi.hssf.util.Region;

public class TableExcel<T> {

//表格标题
private String title;
//单元格宽度
private int colWidth = 20;
//行高度
private int rowHeight = 20;

private HSSFWorkbook workbook;

//表头样式
private HSSFCellStyle styleHead;
//主体样式
private HSSFCellStyle styleBody;
//日期格式化,默认yyyy-MM-dd HH:mm:ss
private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

public TableExcel(String title,int colWidth,int rowHeight,String dateFormat){
this.colWidth = colWidth;
this.rowHeight = rowHeight;
this.title = title;
workbook = new HSSFWorkbook();
sdf = new SimpleDateFormat(dateFormat);
init();
}

public TableExcel(String title,int colWidth,int rowHeight){
this.colWidth = colWidth;
this.rowHeight = rowHeight;
this.title = title;
workbook = new HSSFWorkbook();
init();
}

public TableExcel(String title){
this.title = title;
workbook = new HSSFWorkbook();
init();
}

private void init(){
// 生成一个样式
styleHead = workbook.createCellStyle();
// 设置这些样式
//styleHead.setFillForegroundColor(HSSFColor.SKY_BLUE.index);
styleHead.setFillForegroundColor(HSSFColor.AQUA.index);
styleHead.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
styleHead.setBorderBottom(HSSFCellStyle.BORDER_THIN);
styleHead.setBorderLeft(HSSFCellStyle.BORDER_THIN);
styleHead.setBorderRight(HSSFCellStyle.BORDER_THIN);
styleHead.setBorderTop(HSSFCellStyle.BORDER_THIN);
styleHead.setAlignment(HSSFCellStyle.ALIGN_CENTER);
// 生成一个字体
HSSFFont font = workbook.createFont();
font.setColor(HSSFColor.VIOLET.index);
font.setFontHeightInPoints((short) 12);
font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
// 把字体应用到当前的样式
styleHead.setFont(font);
// 生成并设置另一个样式
styleBody = workbook.createCellStyle();
styleBody.setFillForegroundColor(HSSFColor.WHITE.index);
styleBody.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
styleBody.setBorderBottom(HSSFCellStyle.BORDER_THIN);
styleBody.setBorderLeft(HSSFCellStyle.BORDER_THIN);
styleBody.setBorderRight(HSSFCellStyle.BORDER_THIN);
styleBody.setBorderTop(HSSFCellStyle.BORDER_THIN);
styleBody.setAlignment(HSSFCellStyle.ALIGN_CENTER);
styleBody.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);
// 生成另一个字体
HSSFFont font2 = workbook.createFont();
font2.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);
// 把字体应用到当前的样式
styleBody.setFont(font2);
}

/**
* 拆分sheet，因为每个sheet不能超过6526，否则会报异常
* @param data
* @param listColumn
* void
*/
private void splitDataToSheets(List<T> data,List<Column> listColumn){

int dataCount = data.size();
int maxColumn = 65535;
int pieces = dataCount/maxColumn;
for(int i = 1; i <= pieces;i++){
HSSFSheet sheet = workbook.createSheet(this.title+i);
List<T> subList = data.subList((i-1)*maxColumn, i*maxColumn);
writeSheet(sheet,subList,listColumn);
}

HSSFSheet sheet = workbook.createSheet(this.title+(pieces+1));
writeSheet(sheet, data.subList(pieces*maxColumn, dataCount),listColumn);
}

/**
* 导出Excel,适用于web导出excel
*
* @param sheet
* @param data
*/
private void writeSheet(HSSFSheet sheet, List<T> data,List<Column> listColumn) {
try {
sheet.setDefaultColumnWidth(colWidth);
sheet.setDefaultRowHeightInPoints(rowHeight);

createHead(listColumn,sheet);
writeSheetContent(listColumn,data,sheet);
} catch (Exception e) {
throw new RuntimeException(e);
}
}

/**
* 导出表格
* @param listColumn
* @param datas
* @return
* @throws Exception
*/
public InputStream exportExcel(List<Column> listColumn,List<T> datas) throws Exception {

splitDataToSheets(datas,listColumn);
return save(workbook);
}

/**
* 导出表格
* @param listColumn
* @param datas
* @param FilePath
* @throws FileNotFoundException
* @throws IOException
* void
*/
public void exportExcel(List<Column> listColumn,List<T> datas,String FilePath) throws FileNotFoundException, IOException{
splitDataToSheets(datas,listColumn);
save(workbook,FilePath);
}

/**
* 把数据写入到单元格
* @param listColumn
* @param datas
* @param sheet
* @throws Exception
* void
*/
private void writeSheetContent(List<Column> listColumn,List<T> datas,HSSFSheet sheet) throws Exception{
HSSFRow row = null;
List<Column> listCol = getColumnList(listColumn);

for(int i = 0 , index = 2; i < datas.size(); i++ , index++){
row = sheet.createRow(index);//创建行

for(int j = 0; j < listCol.size(); j++){
Column c = listCol.get(j);
createCol(row,c,datas.get(i),j);
}

}
}

/**
* 把column的columnList整理成一个list<column>
* @param listColumn
* @return
* List<Column>
*/
private List<Column> getColumnList(List<Column> listColumn){

List<Column> listCol = new ArrayList<Column>();
for(int i = 0; i < listColumn.size(); i++){
List<Column> list = listColumn.get(i).getListColumn();
if(list.size() > 0){
for(Column c : list){
if(c.getFieldName() != null){
listCol.add(c);
}

}
}else{
if(listColumn.get(i).getFieldName() != null){
listCol.add(listColumn.get(i));
}

}
}

return listCol;
}

/**
* 保存Excel到InputStream，此方法适合web导出excel
*
* @param workbook
* @return
*/
private InputStream save(HSSFWorkbook workbook) {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
try {
workbook.write(bos);
InputStream bis = new ByteArrayInputStream(bos.toByteArray());
return bis;
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}

private void save(HSSFWorkbook workbook,String filePath) throws FileNotFoundException, IOException{

workbook.write(new FileOutputStream(filePath));
}

/**
* 创建行
* @param row
* @param column
* @param v
* @param j
* @return
* @throws Exception
*/
public int createRowVal(HSSFRow row,Column column,T v,int j) throws Exception{
//便利标题
if(column.getListColumn() != null && column.getListColumn().size() > 0){
for(int i = 0; i < column.getListColumn().size(); i++){
createRowVal(row,column.getListColumn().get(i),v,j);
}
}else{
createCol(row,column,v,j++);

}
return j;

}

/**
* 创建单元格
* @param row
* @param column
* @param v
* @param j
* @throws Exception
*/
public void createCol(HSSFRow row,Column column,T v,int j) throws Exception{
HSSFCell cell = row.createCell(j);  //创建单元格
cell.setCellStyle(styleBody); //设置单元格样式
Class cls = v.getClass();
Field field = cls.getDeclaredField(column.getFieldName());
field.setAccessible(true); //设置些属性是可以访问的
if(field.get(v) != null){
Object value = field.get(v);
if(value instanceof Date){
value = parseDate((Date)value);
}

HSSFRichTextString richString = new HSSFRichTextString(value.toString());
cell.setCellValue(richString);
}
}

/**
* 时间转换
* @param date
* @return
* String
*/
private  String parseDate(Date date){
String dateStr = "";
try{
dateStr = sdf.format(date);
} catch (Exception e){
e.printStackTrace();
}

return dateStr;
}

/**
* 创建表头
* @param listColumn
*/
public void createHead(List<Column> listColumn,HSSFSheet sheetCo){
HSSFRow row = sheetCo.createRow(0);
HSSFRow row2 = sheetCo.createRow(1);

for(short i = 0, n = 0; i < listColumn.size(); i++){//i是headers的索引，n是Excel的索引
HSSFCell cell1 = row.createCell(n);
cell1.setCellStyle(sty
aacc
leHead); //设置表头样式
HSSFRichTextString text = null;
List<Column> columns = listColumn.get(i).getListColumn();
if(columns != null && columns.size() > 0){//双标题
text = new HSSFRichTextString(listColumn.get(i).getContent());
sheetCo.addMergedRegion(new Region(0, n, 0, (short) (n + columns.size() -1)));//创建第一行大标题

short tempI = n;
for(int j = 0; j < columns.size(); j++){//添加标题样式
HSSFCell cellT = row.createCell(tempI++);
cellT.setCellStyle(styleHead);
}
for(int j = 0; j < columns.size(); j++){  //给标题复制
HSSFCell cell2 = row2.createCell(n++);

cell2.setCellStyle(styleHead);
cell2.setCellValue(new HSSFRichTextString(columns.get(j).getContent()));
}
}else{//单标题
//sheetCo.setColumnWidth(i, columns.get(i).getContent().getBytes().length*2*256);
HSSFCell cell2 = row2.createCell(n);
cell2.setCellStyle(styleHead);
text = new HSSFRichTextString(listColumn.get(i).getContent());
sheetCo.addMergedRegion(new Region(0, n, 1, n));
n++;
}
cell1.setCellValue(text);
}

}

public int getColWidth() {
return colWidth;
}

public void setColWidth(int colWidth) {
this.colWidth = colWidth;
}

public int getRowHeight() {
return rowHeight;
}

public void setRowHeight(int rowHeight) {
this.rowHeight = rowHeight;
}

public HSSFWorkbook getWorkbook() {
return workbook;
}

public void setWorkbook(HSSFWorkbook workbook) {
this.workbook = workbook;
}

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}

public HSSFCellStyle getStyleHead() {
return styleHead;
}

public void setStyleHead(HSSFCellStyle styleHead) {
this.styleHead = styleHead;
}

public HSSFCellStyle getStyleBody() {
return styleBody;
}

public void setStyleBody(HSSFCellStyle styleBody) {
this.styleBody = styleBody;
}

}

2：单元格类Column

import java.util.ArrayList;
import java.util.List;

public class Column {
//单元格内容
private String content;
//字段名称，用户导出表格时反射调用
private String fieldName;
//这个单元格的集合
private List<Column> listColumn = new ArrayList<Column>();

public Column(String content,String fieldName){
this.content = content;
this.fieldName = fieldName;
}

public String getContent() {
return content;
}

public void setContent(String content) {
this.content = content;
}

public String getFieldName() {
return fieldName;
}
public void setFieldName(String fieldName) {
this.fieldName = fieldName;
}

public List<Column> getListColumn() {
return listColumn;
}

public void setListColumn(List<Column> listColumn) {
this.listColumn = listColumn;
}

}

/**
* 测试方法
* @param args
* @throws Exception
* void
*/
public static void main(String[] args) throws Exception {

List<Column> listColumn = new ArrayList<Column>();//用于存放第一行单元格

List<Column> list2 = new ArrayList<Column>();//用于存放第一列第二行的单元格
list2.add(new Column("标题1","value1"));//创建一列，value1 表示这一列需要导出字段的值
list2.add(new Column("标题2","value1"));
list2.add(new Column("标题3","value1"));
list2.add(new Column("标题4","value1"));
list2.add(new Column("标题5","value1"));

List<Column> list3  = new ArrayList<Column>();//用于存放第二列第二行的单元格
list3.add(new Column("标题6","value2"));
list3.add(new Column("标题7","value2"));
list3.add(new Column("标题8","value2"));
list3.add(new Column("标题9","value2"));

Column c1 = new Column("标题1",null);//创建第一行大标题,大标题的fieldName 为 null
c1.setListColumn(list2);//所属c1的单元格都赋值给c1
Column c2 = new Column("标题2",null);
c2.setListColumn(list3);
listColumn.add(c1);
listColumn.add(c2);

List<ValueObj> valueList = new ArrayList<ValueObj>();//需要导出的数据
valueList.add(new ValueObj("1","11"));
valueList.add(new ValueObj("2","22"));
valueList.add(new ValueObj("3","33"));
valueList.add(new ValueObj("4","44"));
valueList.add(new ValueObj("5","55"));
valueList.add(new ValueObj("6","66"));
valueList.add(new ValueObj("7","77"));

TableExcel<ValueObj> ta = new TableExcel<ValueObj>("表格",15,20);
ta.exportExcel(listColumn, valueList,"D://outExcel.xls");

}

导出的结果：