java中IO流(指定文件夹创建文件及写入)

**java中IO流(指定文件夹创建文件，将mysql表查询结果写入创建文件)

import com.csvreader.CsvWriter;
import java.io.*;
import java.nio.charset.Charset;
import java.sql.*;
import java.text.SimpleDateFormat;
import java.util.Date;

public class ExportCsv {
	
	//数据库连接
    private static final String URL = "jdbc:mysql://localhost:3306/jswms?serverTimezone=GMT%2B8";
    private static final String NAME = "root";
    private static final String PASSWORD = "1QAZ2wsx";
    


    public static void main(String[] args) throws Exception {
    	//以当前日期定义文件名称
        Date date = new Date();   //获取当前时间
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  //定义文件内容时间格式
        String formatDate = sdf.format(date);   //把当前时间以定义的格式 格式化
        SimpleDateFormat sdf1 = new SimpleDateFormat("yyyyMMdd");  //定义文件名时间格式
        String fileDate = sdf1.format(date)+"File";
    	String nameDateBook = "F:\\FileBook\\"+fileDate+".csv";   //获得文件名
		//把时间格式化成字符串
		RandomAccessFile out_rand = new RandomAccessFile(nameDateBook,"rw");  
		//out_rand.writeBytes(formatDate);  //写入时间
		System.err.println("创建时间文件成功，文件名为："+nameDateBook);
		out_rand.close();
		
    	
        //1.加载驱动程序
	    Class.forName("com.mysql.jdbc.Driver");
        //2.获得数据库的连接
        Connection conn = DriverManager.getConnection(URL, NAME, PASSWORD);
        //3.通过数据库的连接操作数据库，实现增删改查
        Statement stmt = conn.createStatement();
        Statement statement = conn.createStatement();
        System.err.println("数据库连接成功");
        // TODO 获取数据
        ResultSet resultSet = statement.executeQuery("select * from alarm_station;");
        ResultSetMetaData metaData = resultSet.getMetaData();
        int columnCount = metaData.getColumnCount();
		FileOutputStream out = new FileOutputStream(nameDateBook);
   
        try {
            CsvWriter csvWriter = new CsvWriter(nameDateBook, ',', Charset.forName("UTF-8"));
            //写入表头信息
            String[] header = new String[columnCount];
            for (int i = 0; i < columnCount; i++) {
                header[i] = metaData.getColumnName(i + 1);
            }
            csvWriter.writeRecord(header);
            //写入内容信息
            while (resultSet.next()) {

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

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

            //关闭写入的流
            csvWriter.close();
            File fileLoad = new File(nameDateBook);
            FileInputStream in = new java.io.FileInputStream(fileLoad);
            //每次写入10240个字节
            byte[] b = new byte[10240];
            int n;
            while ((n = in.read(b)) != -1) {
                out.write(b, 0, n); //每次写入out1024字节
            }
            System.out.println("《《《《《《写入成功》》》》》》");
            out.close();
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

控制台输出：

代码可直接上用，注意不要导错包，希望可以帮助到有需要的朋友
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