java實現查詢數據庫中所有表格數據

package ASS;

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

public class Aa {

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

        String a = "lianxi";// 選擇什么數據庫
        String[] q = new String[100];
        String[] w = new String[100];
        int t=0;
        

        Class.forName("com.mysql.jdbc.Driver");

        Connection aa = DriverManager.getConnection("jdbc:mysql:///" + a + "",
                "root", "");
        Statement ff = aa.createStatement();
        Statement qq = aa.createStatement();
        Statement www = aa.createStatement();
        ResultSet g = ff.executeQuery("Show tables");// 查詢此數據庫有多少個表格

        while(g.next()){
            System.out.println(g.getString(1));
            q[t]=g.getString(1);//把表名給賦值給數組
            ResultSet u=qq.executeQuery("DESC "+q[t]+"");//以數組來查一下此表格的列
            int l=0;
            while(u.next()){
                w[l++]=u.getString(1);//獲取此表的列數
                
            }
            ResultSet y=www.executeQuery("select * from "+q[t++]+"");//查詢此表的數據
            while(y.next()){//獲取此表數據
                for (int i = 1; i < l+1; i++) {//以列的數值為終止行，來打印！
                    
                    System.out.print(y.getString(i)+"\t");
                }
                System.out.println();
            }
        }
        g.close();
        ff.close();
        aa.close();

    }
}