Java Excel 导出数据

之前做过一遍找不到了，前几天参考网上的写了个发现织入标题时 数据少一条，修改了下demo贴上，方便下次查阅。

/**
 * @ClassName TestExcle
 * @Author lz
 * @Date 2018/10/8 16:23
 * @Version 1.0.0
 * @Desciption
 **/
public class TestExcle {


    public static void main(String[] args) throws Exception {
        TestExcle tm = new TestExcle();
        tm.jdbcex(true);
    }
    public void jdbcex(boolean isClose) throws InstantiationException, IllegalAccessException,
            ClassNotFoundException, SQLException, IOException, InterruptedException {

        String[] titles = {"id","name"};
        String xlsFile = "D:/demo.xlsx";		//输出文件
        //内存中只创建100个对象，写临时文件，当超过100条，就将内存中不用的对象释放。
        Workbook wb = new SXSSFWorkbook(100);			//关键语句
        Sheet sheet = null;		//工作表对象
        Row nRow = null;		//行对象
        Cell nCell = null;		//列对象

        //使用jdbc链接数据库
        Class.forName("com.mysql.jdbc.Driver").newInstance();
        String url = "jdbc:mysql://localhost:3306/test2?characterEncoding=UTF-8";
        String user = "root";
        String password = "123456";
        //获取数据库连接
        Connection conn = DriverManager.getConnection(url, user,password);
        Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
        String sql = "select * from t1 limit 1000000";   //100万测试数据
        ResultSet rs = stmt.executeQuery(sql);

        ResultSetMetaData rsmd = rs.getMetaData();
        long  startTime = System.currentTimeMillis();	//开始时间
        System.out.println("strat execute time: " + startTime);

        int rowNo = 0;		//总行号
        int pageRowNo = 0;	//页行号

        while(rs.next()) {
            //打印300000条后切换到下个工作表，可根据需要自行拓展，2百万，3百万...数据一样操作，只要不超过1048576就可以
            if(rowNo%300000==0){
                System.out.println("Current Sheet:" + rowNo/300000);
                sheet = wb.createSheet("我的第"+(rowNo/300000)+"个工作簿");//建立新的sheet对象
                sheet = wb.getSheetAt(rowNo/300000);		//动态指定当前的工作表
                pageRowNo = 0;		//每当新建了工作表就将当前工作表的行号重置为0
            }
            rowNo++;
            nRow = sheet.createRow(pageRowNo++);	//新建行对象

            if(pageRowNo==1){
                for (int i = 0; i <titles.length ; i++) {
                    nCell = nRow.createCell(i);
                    nCell.setCellValue(titles[i]);
                }
                nRow = sheet.createRow(pageRowNo++);	//新建行对象
                rowNo++;
            }

            // 打印每行，每行有6列数据   rsmd.getColumnCount()==6 --- 列属性的个数
            for(int j=0;j<rsmd.getColumnCount();j++){
                System.out.println("_______________"+pageRowNo);
                nCell = nRow.createCell(j);
                nCell.setCellValue(rs.getString(j+1));
            }

            if(rowNo%10000==0){
                System.out.println("row no: " + rowNo);
            }
//		Thread.sleep(1);	//休息一下，防止对CPU占用，其实影响不大
        }

        long finishedTime = System.currentTimeMillis();	//处理完成时间
        System.out.println("finished execute  time: " + (finishedTime - startTime)/1000 + "m");

        FileOutputStream fOut = new FileOutputStream(xlsFile);
        wb.write(fOut);
        fOut.flush();		//刷新缓冲区
        fOut.close();

        long stopTime = System.currentTimeMillis();		//写文件时间
        System.out.println("write xlsx file time: " + (stopTime - startTime)/1000 + "m");

        if(isClose){
            this.close(rs, stmt, conn);
        }
    }

    //执行关闭流的操作
    private void close(ResultSet rs, Statement stmt, Connection conn ) throws SQLException{
        rs.close();
        stmt.close();
        conn.close();
    }


}