jdbc封装类DbUtils操作（官方）

 

public class dbutilstext {
    public static void main(String[] args) {
        try {
            Connection c =DriverManager.getConnection("jdbc:mysql:/db1?user=aa");
//            System.out.println(c);
            QueryRunner qu =new QueryRunner();

//          Map<String, Object> list= qu.query(c,"select * from stu",new MapHandler());//查询一个
            List<Map<String, Object>> list= qu.query(c,"select * from stu",new MapListHandler());//查询全部
          System.out.println(list);
          //查询一个值
            String name = qu.query(c,"select name from stu where id=?",new ScalarHandler<>(),6);
            System.out.println(name);

           long name2=qu.query(c,"select count(*)from stu where score >=?",new ScalarHandler<>(),60);//多少个
            System.out.println(name2);
            List<String> ne =qu.query(c,"select name from stu ",new ColumnListHandler<>());//一列
            System.out.println(ne);
            List<Map<String, Object>> ma =qu.query(c,"select name,score from stu",new MapListHandler());//可以实现一列至多列
            System.out.println(ma);
            System.out.println("=============================================================");

            //BeanListHandler封装对象
            List<Student> lss =qu.query(c,"select id,name,score from stu",new BeanListHandler<>(Student.class));
            System.out.println(lss);
            //显示所有人的姓名
            for (Student tt:lss){
                System.out.println(tt.getName());
            }
            Student stt =qu.query(c,"select id,name,score from stu where id=?",new BeanHandler<>(Student.class),4);
            System.out.println(stt);

//            创建
//            qu.execute(c,"create database db3");
            qu.update(c,"update stu set name =? where id=?","popo",3);

        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }

    }
}