package utils;
import javax.servlet.http.HttpServletResponse;
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.ss.util.CellRangeAddress;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
public class CommonExcel {
// 显示的导出Excel表的标题(通常第一行)
private String title;
// 导出Excel表的列名(通常第二行)
private String[] rowName;
// 导出Excel表的文件名
private String fileName;
// 导出Excel表的文件主题内容(通常从第三行往下的内容)
// 需要注意的是:主要内容的格式为第一列为数字(序号),从第二列开始都是字符串
// 每一行为Object[]类型,很多行用List包装起来
private List<Object[]> dataList = new ArrayList<Object[]>();
// 用于下载的response
private HttpServletResponse response;
// 构造方法,传入要导出的数据
public CommonExcel(String title, String[] rowName, List<Object[]> dataList, HttpServletResponse response, String fileName) {
this.dataList = dataList;
this.rowName = rowName;
this.title = title;
this.response = response;
this.fileName = fileName;
}
// 下载Excel的方法
public void downloadExcel() throws Exception {
try {
HSSFWorkbook workbook = new HSSFWorkbook(); // 创建工作簿对象
HSSFSheet sheet = workbook.createSheet(title); // 创建工作表
// 产生表格标题行
HSSFRow rowm = sheet.createRow(0);
HSSFCell cellTiltle = rowm.createCell(0);
// sheet样式定义(两个函数均为自定义,可以自行修改)
HSSFCellStyle columnTopStyle = this.getColumnTopStyle(workbook);//获取列头样式对象
HSSFCellStyle style = this.getStyle(workbook); //单元格样式对象
sheet.addMergedRegion(new CellRangeAddress(0, 1, 0, (rowName.length - 1)));
cellTiltle.setCellStyle(columnTopStyle);
cellTiltle.setCellValue(title);
// 定义所需列数
int columnNum = rowName.length;
HSSFRow rowRowName = sheet.createRow(2); // 在索引2的位置创建行(最顶端的行开始的第二行)
// 将列头设置到sheet的单元格中
for (int n = 0; n < columnNum; n++) {
HSSFCell cellRowName = rowRowName.createCell(n); //创建列头对应个数的单元格
cellRowName.setCellType(HSSFCell.CELL_TYPE_STRING); //设置列头单元格的数据类型
HSSFRichTextString text = new HSSFRichTextString(rowName[n]);
cellRowName.setCellValue(text); //设置列头单元格的值
cellRowName.setCellStyle(columnTopStyle); //设置列头单元格样式
}
// 将查询出的数据设置到sheet对应的单元格中
for (int i = 0; i < dataList.size(); i++) {
Object[] obj = dataList.get(i); //遍历每个对象
HSSFRow row = sheet.createRow(i + 3); //创建所需的行数
for (int j = 0; j < obj.length; j++) {
HSSFCell cell = null; //设置单元格的数据类型
if (j == 0) {
cell = row.createCell(j, HSSFCell.CELL_TYPE_NUMERIC); //第一列为数字
cell.setCellValue(i + 1);
} else {
cell = row.createCell(j, HSSFCell.CELL_TYPE_STRING); //第二列起为字符串
if (!"".equals(obj[j]) && obj[j] != null) {
cell.setCellValue(obj[j].toString()); //设置单元格的值
}
}
cell.setCellStyle(style); //设置单元格样式
}
}
//让列宽随着导出的列长自动适应
for (int colNum = 0; colNum < columnNum; colNum++) {
int columnWidth = sheet.getColumnWidth(colNum) / 256;
for (int rowNum = 0; rowNum < sheet.getLastRowNum(); rowNum++) {
HSSFRow currentRow;
//当前行未被使用过
if (sheet.getRow(rowNum) == null) {
currentRow = sheet.createRow(rowNum);
} else {
currentRow = sheet.getRow(rowNum);
}
if (currentRow.getCell(colNum) != null) {
HSSFCell currentCell = currentRow.getCell(colNum);
if (currentCell.getCellType() == HSSFCell.CELL_TYPE_STRING) {
int length = currentCell.getStringCellValue().getBytes().length;
if (columnWidth < length) {
columnWidth = length;
}
}
}
}
if (colNum == 0) {
sheet.setColumnWidth(colNum, (columnWidth - 2) * 256);
} else {
sheet.setColumnWidth(colNum, (columnWidth + 4) * 256);
}
}
}
}