DButils 的使用

1、项目引入commons-dbutils-1.4.jar 

下载地址：

2、使用例子：

//使用c3p0初始化数据源QueryRunner runner = new QueryRunner(new ComboPooledDataSource());//1.ArrayHandler 将查询结果的第一行转换为一个数组对象返回Object[] objs = runner.query("select * from account where name=?",new ArrayHandler() , "si");System.out.println(objs[0]);//2.ArrayHandler 把结果集中的每一行数据都转成一个对象数组，再存放到List中.List<Object[]> list = runner.query("select * from account",new ArrayListHandler() );System.out.println(list.get(1)[1]);//3.BeanHandler,将查询结果的第一行转换为一个JavaBean对象返回Account acc = runner.query("select * from account where name=?",new BeanHandler<Account>(Account.class) , "c");System.out.println(acc);//4.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。List<Account> acclist = runner.query("select * from account",new BeanListHandler<Account>(Account.class) );System.out.println(acclist);//5.MapHandler：将结果集中的第一行数据封装到一个Map里，key是列名，value就是对应的值。Map map = runner.query("select * from account",new MapHandler() );System.out.println(map.get("name").toString());//6.MapListHandler：将结果集中的每一行数据都封装到一个Map里，然后再存放到ListList<Map<String, Object>> maplist = runner.query("select * from account",new MapListHandler() );System.out.println(maplist);//7.ColumnListHandler：将结果集中某一列的数据存放到List中。List<Object> columnList = runner.query("select * from account",new ColumnListHandler(2) );System.out.println(columnList);//8.KeyedHandler(name)：将结果集中的每一行数据都封装到一个Map里(List<Map>)，再把这些map再存到一个map里，其key为指定的列。Map<Object, Map<String, Object>> keymap = runner.query("select * from account",new KeyedHandler("id") );System.out.println(keymap);//9.ScalarHandler: 单值查询//select count(*) from account;Long count = (Long)runner.query("select count(*) from account",new ScalarHandler(1) );System.out.println(count);