JDBC中實現SQL查詢語句: select * from table

廢話不錯說直接上代碼

package Jdbc01;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;

/*
 * 測試ResultSet獲得SQL查詢結果
 * SQL語句: select * from student
 */
public class Demo4 {
    public static void main(String[] args){
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        
        try {
            //注冊類
            Class.forName("com.mysql.cj.jdbc.Driver");
            //建立連接
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/testJDBC?characterEncoding=utf8","root","shmily");
            //查詢語句
            String sql1 = "select * from student";
            ps = conn.prepareStatement(sql1);
            rs = ps.executeQuery();
            //獲取列數
            ResultSetMetaData md= rs.getMetaData();
            int columnSize = md.getColumnCount();
            
            System.out.println("查詢結果如下:");
            //打印字段名
            for(int i = 1; i <= columnSize; i++){
                System.out.printf("%-12s",md.getColumnName(i));
            }
            System.out.println();
            //打印所有記錄
            while(rs.next()) {
                for(int i = 1; i <= columnSize ; i++){
                    System.out.printf("%-12s",rs.getObject(i));
                }
                System.out.println();
            }
            System.out.println("\n結束查詢");
            
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //關閉順序: ResultSet-->Statement-->Connection
            try {
                if(rs!=null) {
                    rs.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            try {
                if(ps!=null) {
                    ps.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            try {
                if(conn!=null) {
                    conn.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        
    }
}

 

 

查詢結果如下:
id          Name        Age         regTime     
1           韓梅梅         15          2019-06-17  
2           李雷          15          2019-06-19  
4           趙靈兒         14          2019-06-19  

結束查詢

 最后請教一下如何讓所有記錄完美對齊?