QueryRunner的使用

public class JdbcUtil {
private static ComboPooledDataSource dataSource =new ComboPooledDataSource();
public static ComboPooledDataSource getDataSource()
{
return dataSource;
}

}

src目录下c3p0-config.xml

 

从数据库中取count(*)数据

        int topicNum=0;
        QueryRunner runner= new QueryRunner(JdbcUtil.getDataSource());
        String sql ="select count(*) from topic where type_id= ? order by time desc";
        Object[] params={typeId};
        topicNum=(int)(long) runner.query(sql,new ScalarHandler(),params);
        return topicNum;

 

取一条数据   其中表的字段名字和类的名字要对应相同

        Topic newlyTopic=null;
        QueryRunner runner= new QueryRunner(JdbcUtil.getDataSource());
        String sql ="select * from topic where type_id= ? order by time desc";
        Object[] params={typeId};
        newlyTopic= runner.query(sql,new BeanHandler<Topic>(Topic.class),params);
        return newlyTopic;

 

取集合数据List<>返回    其中表的字段名字和类的名字要对应相同

        List<Topic> topicList=new ArrayList<Topic>();
        QueryRunner runner= new QueryRunner(JdbcUtil.getDataSource());
        String sql ="select * from topic where type_id= ? order by time desc";
        Object[] params={typeId};
        topicList=runner.query(sql, new BeanListHandler<Topic>(Topic.class),params);
        return topicList;

 插入

        QueryRunner runner= new QueryRunner(JdbcUtil.getDataSource());
        String sql ="insert into topic(name,author,content,time,type_id) values(?,?,?,?,?)";
        Object[] params={topic.getName(),topic.getAuthor(),topic.getContent(),topic.getTime(),topic.getTypeId()};
        try {
            //事务开始
            runner.update(sql,params);
            //事务提交
        } catch (SQLException e) {
            e.printStackTrace();
            //事务回滚
            throw e;
        }

更新

        QueryRunner runner= new QueryRunner(JdbcUtil.getDataSource());
        String sql ="update topic set name=? , content=? , time=? where id= ?";
        Object[] params={topic.getName(),topic.getContent(),topic.getTime(),topic.getId()};
        try {
            //事务开始
            runner.update(sql,params);
            //事务提交
        } catch (SQLException e) {
            e.printStackTrace();
            //事务回滚
            throw e;
        }