Apache的POI：JTable中保存到一个文件 [英] apache poi: saving jtable to a file

问题描述

我最近开始使用Java，当我需要创建一个JTable开始一个Excel文件，我面临与Apache POI库的一些问题。

I've recently started working with java and I'm facing some issues with the apache poi library when I need to create an excel file starting from a jTable.

我读过许多线程，并拿出一些code这是行不通的（即使这是pretty容易的东西，有很多例子，这让我看起来更愚蠢的），并我希望有人能帮助我。

I've read many threads and come up with some code which just won't work (even if this is pretty easy stuff and there were many examples, which makes me look even more dumb) and I was hoping someone could help me out.

所以这里的问题：

）为什么for循环，这是应该写excel文件，无法填补每一个细胞？ （在Excel文件数据的唯一行是第六个，这也使我不知道为什么它计数为getRowCount /列的表模型空项目methods..also我知道这是打印自定义字符串，而不是表本身，而是保存为b点）

a) why does the for loop, which is supposed to write the excel file, not fill every cell? (the only row with data in the excel file is the sixth one, which also makes me wonder why does it count null items in the table model for the getRowCount/Column methods..also I know it's printing a custom String and not the table itself but save that for point b)

B）我怎么使用JTable的模型项目来填充创建表我不得不选择对象列式时，因为excel文件？ （我也有与类型的对象，特别是问题，只要它是一个字符串||整数没有问题可言，但该表应该有这两者似乎不混合，当您尝试合作使用的东西从字符串不同setCellValue（）方法|| integer..or至少我不能使它工作）

b) how am I supposed to use the jtable model items to populate the excel file since when creating the table I had to choose Object as row type? (I'm also having issues with the kind of object especially, as long as it's a String||integer there's no issue at all but the table is supposed to have a mix of both which doesn't seem to work when you try to use the setCellValue() method with something different from the String||integer..or at least I couldn't make it work)

C）让我们说我以后要填充从pviously创建的文件I $ P $ JTable中，我会只需要使用该解决方案到B点）（其他各地的方式即是）读取文件用BufferedReader类后？

c) let's say I'd later want to populate the jtable from the file I previously created, would I simply have to use the solution to point b) (the other way around that is) after reading the file with the bufferedReader class?

声明：的code的第一部分是自动生成的通过NetBeans的，你可能会说，HSSF的一部分，我想出了是在最后，但我想你可能想看整个事情，对不起，如果它看起来有点凌乱。

Disclaimer: the first part of the code is auto-generated by netbeans as you can probably tell, the hssf part I came up with is at the end but I thought you might want to see the whole thing, sorry if it looks kind of messy.

这里的code：

package poitest;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JTable;
import javax.swing.table.TableModel;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;

public class POITestFrame extends javax.swing.JFrame {

    /**
     * Creates new form POITestFrame
     */
    public POITestFrame() {
        initComponents();
    }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents
    private void initComponents() {

        excelButton = new javax.swing.JButton();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTable1 = new javax.swing.JTable();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        excelButton.setText("ESPORTA!");
        excelButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                excelButtonActionPerformed(evt);
            }
        });

        jTable1.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {
                {"Boolean", "Integer", "String", "Array"},
                {"x*y", "x+y", "x/y", "x-y"},
                {"32", "43", "12", "24"},
                {"casa", "cantiere", "museo", "acquario"},
                {null, null, null, null},
                {null, null, null, null}
            },
            new String [] {
                "Title 1", "Title 2", "Title 3", "Title 4"
            }
        ));
        jScrollPane1.setViewportView(jTable1);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 320, Short.MAX_VALUE)
            .addComponent(excelButton, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 91, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(excelButton)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>//GEN-END:initComponents

    private void excelButtonActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_excelButtonActionPerformed
        try {
             PoiWriter(jTable1);
        } catch (FileNotFoundException ex) {
             Logger.getLogger(POITestFrame.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            Logger.getLogger(POITestFrame.class.getName()).log(Level.SEVERE, null, ex);
        }
    }//GEN-LAST:event_excelButtonActionPerformed

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /*
         * Set the Nimbus look and feel
         */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /*
         * If Nimbus (introduced in Java SE 6) is not available, stay with the
         * default look and feel. For details see
         * http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(POITestFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(POITestFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(POITestFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(POITestFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /*
         * Create and display the form
         */
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                new POITestFrame().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify//GEN-BEGIN:variables
    private javax.swing.JButton excelButton;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTable jTable1;
    // End of variables declaration//GEN-END:variables

    private void PoiWriter(JTable jTable1) throws FileNotFoundException, IOException {
        TableModel model = jTable1.getModel();

    // create a workbook
    Workbook wb = new HSSFWorkbook();  // xls file
        // create a new sheet
        Sheet sheet = wb.createSheet("Foglio di Prova!");
        // declare a row object reference
        Row r = null;
        // declare a cell object reference
        Cell c = null;
        // create a new file
    FileOutputStream fos;
    fos = new FileOutputStream("File di Prova.xls");

        // create a sheet table rows
        int rownum;
        for (rownum = (short) 0; rownum < model.getRowCount(); rownum++) {
            // create a row
            r = sheet.createRow(rownum);
        }

        for (short cellnum = (short) 0; cellnum < model.getRowCount(); cellnum ++) {
            // create a numeric cell
            c = r.createCell(cellnum);

            // populate table with custom objects
            for(int i=0; i < model.getRowCount();i++){
            for(int j=0;j < model.getColumnCount();j++){
                String aplala = "blabla";       
                c.setCellValue(aplala);   
            }
        }


        }
        wb.write(fos);
    fos.close();
    }
}

PS：如果你想知道为什么我建的表对象类型：这不是我的工作项目，我做了这个片段来测试HSSF出因为生成Excel是相当可编辑的，但事情不要不像是会顺利。

PS: If you're wondering why I built the table with Object types: this isn't the project I'm working with, I made this snippet to test hssf out since the resulting excel is quite editable but things don't seem to go well.

PPS：我试图与tokenizer类的工作很好，但我不知道你可以编辑生成excel文件尽可能与POI的lib

PPS: I tried working with the tokenizer class as well but I'm not sure you can edit the resulting excel file as much as with poi lib.

PPPS：这是我用java是第一次尝试的话，请不要过于粗糙

PPPS: This is my very first attempt with java so, please, don't be too rough!

我希望问题是不够清楚，在此先感谢，我也正尝试在编程变得更好：P

I hope the questions were clear enough and thanks in advance, I do am trying to get better at programming :P

编辑：实际上，这一天之后就是我想出了这似乎与Apache POI库工作，感谢帮助家伙它给了很好的指针

after a day of practice this is what I came up with which seems to work with the apache poi library, thanks for the help guys it gave good pointers!

    int rowNum;
    int colNum;
    int tempRows;
    int rowCount = model.getRowCount();
    int columnCount = model.getColumnCount();     

    // create the headers
    for (colNum = 0; colNum < columnCount; colNum++) {             
        if (colNum == 0) {
            r = sheet.createRow(0);
        }            
        c = r.createCell(colNum);  
        c.setCellValue(model.getColumnName(colNum)); 
    }

    for (rowNum = 0; rowNum < rowCount; rowNum++) {
        // create rows + 1 (to account for the headers) 
        tempRows = rowNum + 1;
        r = sheet.createRow(tempRows);      

        for (short cellnum = 0; cellnum < columnCount; cellnum ++) {
            // create cells 
            c = r.createCell(cellnum);
            // add values from table
            c.setCellValue(model.getValueAt(rowNum, cellnum).toString());
        } 
    } 

随意发表评论，如果你觉得code可以改善，建议总是欢迎，特别是像我这样的新人;）

Feel free to comment if you think the code can be improved, suggestions are always welcome, especially to newcomers like myself ;)

再次感谢您的提示，他们真的做了把戏^^

Again, thanks for the tips, they really did the trick ^^

推荐答案

请阅读的的JTable ，创建表型号和实现的数据类型中，的JTable 知道那些列类，并返回正确的值输出到 POI ;在MS Excel的大多数类型：

Please read the tutorial about JTable, Creating a Table Model and implemented data types, JTable knows those Column Classes, and returns proper value for output to POI; for most of types in the MS Excel:

1. 您必须循环内当前行中的单元格，太

1. you have to loop inside cells in current row, too

必须格式化为各种数据类型的输出（日期，双击，字符串）

have to format output for various data types (Date, Double, String)

然后就可以集中精力创建式（S）和着色单元（S）

then you can focus on creating formula(s) and coloring cell(s)

$ C $到c循环的TableModel 可以生成MS Excel文件，也与标准窗户分隔符：

Code to loop through TableModel can generate MS Excel File, too, with standard windows delimiters:

public class ExcelCustomerReport {

    public ExcelCustomerReport() {
    }

    public void exportTable(JTable table, File file) throws IOException {
        TableModel model = table.getModel();
        FileWriter out = new FileWriter(file);
        String groupExport = "";
        for (int i = 0; i < (model.getColumnCount()); i++) {//* disable export from TableHeaders
            groupExport = String.valueOf(model.getColumnName(i));
            out.write(String.valueOf(groupExport) + "\t");
        }
        out.write("\n");
        for (int i = 0; i < model.getRowCount(); i++) {
            for (int j = 0; j < (model.getColumnCount()); j++) {
                if (model.getValueAt(i, j) == null) {
                    out.write("null" + "\t");
                } else {
                    groupExport = String.valueOf(model.getValueAt(i, j));
                    out.write(String.valueOf(groupExport) + "\t");
                }
            }
            out.write("\n");
        }
        out.close();
    }
}

这篇关于Apache的POI：JTable中保存到一个文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！