java 导出excel(读数据库案例)

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class SheetDataSource {
public static Connection getConn() throws Exception{
Class.forName("com.mysql.jdbc.Driver");
return DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "*****", "******");
}
public static ResultSet selectAllDataFromDB() throws Exception{
Connection conn = getConn();
Statement sm = conn.createStatement();
return sm.executeQuery("select * from user");
}
}

============================================================

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.*;
import javax.swing.JOptionPane;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFFooter;
import org.apache.poi.hssf.usermodel.HSSFHeader;
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.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Color;
import org.apache.poi.ss.usermodel.Font;

public class ExcelService {
// 表头
public static final String[] tableHeader = {"id","username","age"};
// 创建工作本
public static HSSFWorkbook demoWorkBook = new HSSFWorkbook();
// 创建表
public static HSSFSheet demoSheet = demoWorkBook.createSheet("用户信息");
// 表头的单元格个数目
public static final short cellNumber = (short)tableHeader.length;
// 数据库表的列数
public static final int columNumber = cellNumber; //3
/**
* 34.* 创建表头 35.*
*
* @return 36.
*/
@SuppressWarnings("deprecation")
public static void createTableHeader()
{
//设置表头，从sheet中得到
HSSFHeader header = demoSheet.getHeader();
header.setCenter("用户表");
//创建一行
HSSFRow headerRow = demoSheet.createRow((short) 0);
for(int i = 0;i < cellNumber;i++)
{
//创建一个单元格
HSSFCell headerCell = headerRow.createCell((short) i);
// headerCell.setEncoding(HSSFCell.ENCODING_UTF_16);
// CellStyle cs = new CellStyle();
//设置cell的值
System.out.println("tableHeader[i]=="+tableHeader[i]);
headerCell.setCellValue(tableHeader[i]);
}
}
/**
* 50.* 创建行 51.*
*
* @param cells
* 52.*
* @param rowIndex
*/
@SuppressWarnings("deprecation")
public static void createTableRow(List<String> cells , short rowIndex)
{
// 创建第rowIndex行
HSSFRow row = demoSheet.createRow((short) rowIndex);
for(short i = 0;i < cells.size();i++)
{
// 创建第i个单元格
HSSFCell cell = row.createCell((short) i);
//cell.setEncoding(HSSFCell.ENCODING_UTF_16);
cell.setCellValue(cells.get(i));
}
}
/**
* 68.* 创建整个Excel表 69.*
*
* @throws SQLException
* 70.* 71.
*/
public static void createExcelSheeet() throws Exception
{
createTableHeader(); //--->创建一个表头行
ResultSet rs = SheetDataSource.selectAllDataFromDB(); //--->得到所有数据
int rowIndex = 1;
while(rs.next())
{
List<String> list = new ArrayList<String>();
for(int i = 1;i <= columNumber;i++)
{
list.add(rs.getString(i));
}
createTableRow(list,(short)rowIndex);
rowIndex++;
}
}
/**
* 89.* 导出表格 90.*
*
* @param sheet
* 91.*
* @param os
* 92.*
* @throws IOException
* 93.
*/
public void exportExcel(HSSFSheet sheet,OutputStream os) throws IOException
{
sheet.setGridsPrinted(true);
HSSFFooter footer = sheet.getFooter();
footer.setRight("Page " + HSSFFooter.page() + " of " +
HSSFFooter.numPages());
System.out.println("HSSFFooter.page()="+HSSFFooter.page()+" "+"HSSFFooter.numPages()="+HSSFFooter.numPages());
demoWorkBook.write(os);
}
public static void main(String[] args) {
String fileName = "D:\\用户信息.xls";
FileOutputStream fos = null;
try {
ExcelService pd = new ExcelService();
ExcelService.createExcelSheeet();
fos = new FileOutputStream(fileName);
pd.exportExcel(demoSheet,fos);
JOptionPane.showMessageDialog(null, "表格已成功导出到 : "+fileName);
} catch (Exception e) {
JOptionPane.showMessageDialog(null, "表格导出出错，错误信息 ："+e+"\n错误原因可能是表格已经打开。");
e.printStackTrace();
} finally {
try {
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}

======================================================

用到的jar包

poi-3.8.jar
poi-examples-3.8.jar
poi-excelant-3.8.jar
poi-ooxml-3.8.jar
poi-ooxml-schemas-3.8.jar
poi-scratchpad-3.8.jar