JavaWeb开发05——DbUtils使用

DbUtils使用

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一.增删改

1.增长数据

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.改变数据

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

二.查询数据

1.ScalarHandler:获取结果集中第一行数据指定列的值,经常使用来进行单值查询

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：将结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：将结果集中的每一行数据都封装到一个对应的JavaBean实例中，存放到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);
    }

实例：客户查询系统

客户查询系统(https://segmentfault.com/a/11...