java连接数据库执行SQL并把查询到的数据保存到磁盘

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import org.junit.Test;


public class TestDemo {

    
    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
    static final String DB_URL = "jdbc:mysql://10.7.164.107:3306/databaseName";
    
    @Test
    public void Test1() throws ClassNotFoundException, SQLException, FileNotFoundException {
        //设置查询到的数据存储地点
        
        //设置数据库用户名密码
        final String USER = "root";
        final String PASS = "password";
        Connection conn = null;
        Statement stmt = null;
        
        //设置查询到的数据存储地点
        FileOutputStream fos = new FileOutputStream(System.getProperty("user.dir")+"\src\topsec\test.txt",true);
        PrintStream p = new PrintStream(fos);
        
        try {
            conn = DriverManager.getConnection(DB_URL,USER,PASS); //连接数据库
            System.out.println("连接数据库成功");
            Class.forName(JDBC_DRIVER);//加载JDBC
            stmt = conn.createStatement();//创建Statement对象
            String sql = "";
            ResultSet rs = stmt.executeQuery(sql);//创建数据对象
            
            //遍历数据对象，把数据存到txt
            while (rs.next()){
                String taskId  = rs.getString("taskId");
                String processInstanceld = rs.getString("processInstanceId");
                String order_id = rs.getString("order_id");
                p.println(taskId+","+order_id+","+processInstanceld);
            }
            p.close();
            rs.close();
            stmt.close();
            conn.close();
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            // 关闭资源
            try{
                if(stmt!=null) stmt.close();
            }catch(SQLException se2){
            }
            try{
                if(conn!=null) conn.close();
            }catch(SQLException se){
                se.printStackTrace();
            }
        }
        
         System.out.println("数据收集完成!");
        
    }
}