Question

我正在使用apache poi在excelsheet上编写mongodb数据，但是它的写作首先在excel的第一行插入数据，但我需要在第一行插入数据，我想在excelsheet上打印最后一行，有人可以帮助我怎么做这是我的代码。

public static void main(String args[]) throws IOException {
    XSSFWorkbook workbook = new XSSFWorkbook();
    XSSFSheet sheet = workbook.createSheet("Sheet1");
    //HSSFSheet sheet = wb.createSheet("Excel Sheet");
    XSSFRow rowhead;
    rowhead = sheet.createRow(0);
    rowhead.createCell(0).setCellValue("Employee ID");
    rowhead.createCell(1).setCellValue("Name");
    rowhead.createCell(2).setCellValue("Phone Number");
    rowhead.createCell(3).setCellValue("Domain");
    rowhead.createCell(4).setCellValue("Address");


    try {

        // To connect to mongodb server
        MongoClient mongoClient = new MongoClient("localhost", 27017);

        // Now connect to your databases
        DB db = mongoClient.getDB("test");
        System.out.println("Connect to database successfully");

        DBCollection collection = db.getCollection("testCollection");
        System.out.println("Collection mycol selected successfully");

        DBCursor cursor = collection.find();
        int i = 1;
        while (cursor.hasNext()) {
            DBObject o = cursor.next();
            //String fname = (String) o.get("Employee ID") ; 
            String lname = (String) o.get("Name");
            String sid = (String) o.get("Phone Number");
            String prg = (String) o.get("Domain");
            String lvl = (String) o.get("Address");

            Row row = sheet.createRow(i);
            row.createCell(0).setCellValue(lname);
            row.createCell(1).setCellValue(sid);
            row.createCell(2).setCellValue(prg);
            row.createCell(3).setCellValue(lvl);
            i++;

        }
    } catch (Exception e) {
        System.err.println(e.getClass().getName() + ": " + e.getMessage());
    }

    try (FileOutputStream outputStream = new FileOutputStream("datasheet.xlsx")) {
        workbook.write(outputStream);
    }

}

Answer 1

如果当前正在以与您想要查看行的方式完全相反的顺序创建Excel，则可以创建包含DBObjects和

的Deque对象（myDeque）

myDeque.addFirst(o);

直到你完成＆＃34; cursor.hasNext（）＆＃34;循环。
之后你可以设置

DBObject o = myDeque.removeFirst();

并且您可以在将行添加到Excel时进行迭代，直到Deque对象为空。

根据要求，代码如下：

import java.util.Deque;
//Other Imports here

public static void main(String args[]) throws IOException {
    XSSFWorkbook workbook = new XSSFWorkbook();
    XSSFSheet sheet = workbook.createSheet("Sheet1");
    //HSSFSheet sheet = wb.createSheet("Excel Sheet");
    XSSFRow rowhead;
    rowhead = sheet.createRow(0);
    rowhead.createCell(0).setCellValue("Employee ID");
    rowhead.createCell(1).setCellValue("Name");
    rowhead.createCell(2).setCellValue("Phone Number");
    rowhead.createCell(3).setCellValue("Domain");
    rowhead.createCell(4).setCellValue("Address");


    try {

        // To connect to mongodb server
        MongoClient mongoClient = new MongoClient("localhost", 27017);

        // Now connect to your databases
        DB db = mongoClient.getDB("test");
        System.out.println("Connect to database successfully");

        DBCollection collection = db.getCollection("testCollection");
        System.out.println("Collection mycol selected successfully");

        DBCursor cursor = collection.find();
        Deque<DBObject> stack = new Deque<>();
        int i = 1;
        while (cursor.hasNext()) {
            DBObject o = cursor.next();
            stack.addFirst(o);
        }
        while(!stack.isEmpty()){
            o = stack.removeFirst();
            //String fname = (String) o.get("Employee ID") ; 
            String lname = (String) o.get("Name");
            String sid = (String) o.get("Phone Number");
            String prg = (String) o.get("Domain");
            String lvl = (String) o.get("Address");

            Row row = sheet.createRow(i);
            row.createCell(0).setCellValue(lname);
            row.createCell(1).setCellValue(sid);
            row.createCell(2).setCellValue(prg);
            row.createCell(3).setCellValue(lvl);
            i++;

        }
    } catch (Exception e) {
        System.err.println(e.getClass().getName() + ": " + e.getMessage());
    }

    try (FileOutputStream outputStream = new FileOutputStream("datasheet.xlsx")) {
        workbook.write(outputStream);
    }

}

Answer 2

它正好用于Last in first out cursor.sort（new BasicDBObject（“_ id”， - 1））;

如何在excelsheet上首先写入最后插入的数据？

2 个答案: