java導出csv、excel

首先新建一個maven項目，添加相關依賴：

使用poi導出excel依賴：

 

<dependency>
   <groupId>org.apache.poi</groupId>
   <artifactId>poi</artifactId>
   <version>3.16</version>
</dependency>
<dependency>
   <groupId>org.apache.poi</groupId>
   <artifactId>poi-ooxml</artifactId>
   <version>3.16</version>
</dependency>

 

添加csv相關工具類依賴：

 

<!-- https://mvnrepository.com/artifact/net.sourceforge.javacsv/javacsv -->
<dependency>
   <groupId>net.sourceforge.javacsv</groupId>
   <artifactId>javacsv</artifactId>
   <version>2.0</version>
</dependency>

 

2、構建執行代碼

（1）、數據導出為excel文件：

 

package com.hwinfo.excel.poi.export;

import com.hwinfo.excel.poi.util.OutputUtil;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.util.CellRangeAddress;

import java.io.FileOutputStream;
import java.io.IOException;
import java.sql.*;

/**
 * @Time : 2019/4/8 0008 14:05
 * @Author : lisheng
 * @Description:
 **/
public class ExportExcel {

    //    private static final String URL = "jdbc:mysql://192.168.101.217:3306/test";
//    private static final String NAME = "dev";
//    private static final String PASSWORD = "lJZx2Ik5eqX3xBDp";
    private static final String URL = "jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8";
    private static final String NAME = "root";
    private static final String PASSWORD = "123456";

    public static void main(String[] args) throws Exception {


        //1.加載驅動程序
        Class.forName("com.mysql.jdbc.Driver");
        //2.獲得數據庫的連接
        Connection conn = DriverManager.getConnection(URL, NAME, PASSWORD);
        //3.通過數據庫的連接操作數據庫，實現增刪改查
        Statement stmt = conn.createStatement();
        Statement statement = conn.createStatement();
        // TODO 獲取數據
        ResultSet resultSet = statement.executeQuery(" select * from area_code order by code limit 50000");
        ResultSetMetaData metaData = resultSet.getMetaData();
       int columnCount = metaData.getColumnCount();

        // TODO 創建HSSFWorkbook對象(excel的文檔對象)
        HSSFWorkbook wb = new HSSFWorkbook();
        // TODO 設置字體格式大小
        HSSFFont font = wb.createFont();
        font.setFontName("宋體");
        font.setFontHeightInPoints((short) 14);//設置字體大小
        HSSFCellStyle cellStyle = wb.createCellStyle();
        cellStyle.setAlignment(HorizontalAlignment.CENTER); // 居中
        cellStyle.setFont(font);

        //建立新的sheet對象（excel的表單）
        HSSFSheet sheet = wb.createSheet("用戶表");
        //在sheet里創建第一行，參數為行索引(excel的行)，可以是0～65535之間的任何一個
        HSSFRow row1 = sheet.createRow(0);
        row1.setHeight((short)500);
        //創建單元格（excel的單元格，參數為列索引，可以是0～255之間的任何一個
        HSSFCell cell = row1.createCell(0);

        //設置單元格內容
        cell.setCellStyle(cellStyle);
        cell.setCellValue("用戶信息表");

        //合並單元格CellRangeAddress構造參數依次表示起始行，截至行，起始列， 截至列
        sheet.addMergedRegion(new CellRangeAddress(0, 0, 0, columnCount-1));

        //在sheet里創建第二行
        HSSFRow row2 = sheet.createRow(1);
        row2.setHeight((short) 500);

        //創建單元格並設置單元格內容
        for (int i = 0; i < columnCount; i++) {
            sheet.setColumnWidth(i,30*256);
            HSSFCell cell1 = row2.createCell(i);
            cell1.setCellStyle(cellStyle);
            cell1.setCellValue(metaData.getColumnName(i + 1));

        }


        int b = 2;
        //數據導入單元格
        while (resultSet.next()) {
            HSSFRow row = sheet.createRow(b);
            row.setHeight((short) 500);
            for (int i = 0; i < columnCount; i++) {
                HSSFCell cell1 = row.createCell(i);
                cell1.setCellStyle(cellStyle);
                cell1.setCellValue(resultSet.getString(metaData.getColumnName(i + 1)));
            }
            b++;
        }

        //輸出Excel文件
        try {
            FileOutputStream output = new FileOutputStream("d:\\detail.xls");
            wb.write(output);
            output.close();
        } catch (Exception e) {
            e.printStackTrace();
        }


        statement.close();
        conn.close();
        System.out.println("文件成功導出");

    }
}

 

（2）、導出為csv

package com.hwinfo.excel.poi.export;

import com.csvreader.CsvWriter;
import java.io.*;
import java.nio.charset.Charset;
import java.sql.*;

/**
 * @Time : 2019/6/5 0005 15:27
 * @Author : lisheng
 * @Description:
 **/
public class ExportCsv {
    //    private static final String URL = "jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8";
//    private static final String NAME = "root";
//    private static final String PASSWORD = "123456";
    private static final String URL = "jdbc:postgresql://host:port/db";
    private static final String NAME = "user";
    private static final String PASSWORD = "pwd";


    public static void main(String[] args) throws Exception {
        //1.加載驅動程序
//        Class.forName("com.mysql.jdbc.Driver");
        Class.forName("org.postgresql.Driver");
        //2.獲得數據庫的連接
        Connection conn = DriverManager.getConnection(URL, NAME, PASSWORD);
        //3.通過數據庫的連接操作數據庫，實現增刪改查
        Statement stmt = conn.createStatement();
        Statement statement = conn.createStatement();
        // TODO 獲取數據
//        ResultSet resultSet = statement.executeQuery(" select * from area_code order by code limit 50000");
        ResultSet resultSet = statement.executeQuery("select * from area_code;");
        ResultSetMetaData metaData = resultSet.getMetaData();
        int columnCount = metaData.getColumnCount();
        FileOutputStream out = new FileOutputStream("d:\\detail.csv");

        try {
            System.out.println("d:\\detail.csv");
            CsvWriter csvWriter = new CsvWriter("d:\\detail.csv", ',', Charset.forName("UTF-8"));
            //寫入表頭信息
            String[] header = new String[columnCount];
            for (int i = 0; i < columnCount; i++) {
                header[i] = metaData.getColumnName(i + 1);
            }
            csvWriter.writeRecord(header);
            //寫入內容信息
            while (resultSet.next()) {

                for (int i = 0; i < columnCount; i++) {

                    csvWriter.write(resultSet.getString(metaData.getColumnName(i + 1)));
                }
                csvWriter.endRecord();
            }

            //關閉寫入的流
            csvWriter.close();
            File fileLoad = new File("d:\\detail.csv");
            FileInputStream in = new java.io.FileInputStream(fileLoad);
            //每次寫入10240個字節
            byte[] b = new byte[10240];
            int n;
            while ((n = in.read(b)) != -1) {
                out.write(b, 0, n); //每次寫入out1024字節
            }
            out.close();
            in.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}