java实现查询数据库中所有表格数据

Posted 2020-10-24 满小蛮

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";// 选择什么数据库
        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");// 查询此数据库有多少个表格

        while(g.next()){
            System.out.println(g.getString(1));
            q[t]=g.getString(1);//把表名给赋值给数组
            ResultSet u=qq.executeQuery("DESC "+q[t]+"");//以数组来查一下此表格的列
            int l=0;
            while(u.next()){
                w[l++]=u.getString(1);//获取此表的列数
                
            }
            ResultSet y=www.executeQuery("select * from "+q[t++]+"");//查询此表的数据
            while(y.next()){//获取此表数据
                for (int i = 1; i < l+1; i++) {//以列的数值为终止行，来打印！
                    
                    System.out.print(y.getString(i)+"\t");
                }
                System.out.println();
            }
        }
        g.close();
        ff.close();
        aa.close();

    }
}