关于java:JavaWeb开发05DbUtils使用

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一. 增删改

1. 减少数据

public void add() throws SQLException{QueryRunner runner = new MyQueryRunner(new ComboPooledDataSource());
        runner.update("insert into account values(null,?,?)","c",1000);
    }

2. 删除数据

public void del() throws SQLException{QueryRunner runner = new MyQueryRunner(new ComboPooledDataSource());
        runner.update("delete from account where id=?",3);
    }

3. 扭转数据

public void update() throws SQLException{QueryRunner runner = new MyQueryRunner(new ComboPooledDataSource());
        runner.update("update account set money=? where name=?", 777,"a");
    }

二. 查问数据

1.ScalarHandler: 获取后果集中第一行数据指定列的值, 罕用来进行单值查问

    public void test() throws SQLException{QueryRunner runner = new QueryRunner(new ComboPooledDataSource());
        Long count = (Long)runner.query("select count(*) from account",new ScalarHandler());
        System.out.println(count);
    }

2.BeanHandler：将后果集中的第一行数据封装到一个对应的 JavaBean 实例中

public void test() throws SQLException{QueryRunner runner = new QueryRunner(new ComboPooledDataSource());
        Account acc = runner.query("select * from account where money>?", new BeanHandler<Account>(Account.class),500);
        System.out.println(acc);
    }

3.BeanListHandler：将后果集中的每一行数据都封装到一个对应的 JavaBean 实例中，寄存到 List 里。

public void test() throws SQLException{QueryRunner runner = new QueryRunner(new ComboPooledDataSource());
        List<Account>list = runner.query("select * from account where money>?", new BeanListHandler<Account>(Account.class),500);
        System.out.println(list);
    }